sailboat engine noise reduction

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Soundproof Your Inboard Engine And Generator

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Save your voice and regain your floating peaceful refuge by adding soundproofing to your engine and generator.

The best strategy to address noise is by containing it at the source, a good example being the insulation inside this engine cover.

Time spent on the water should be relaxing. But that can be difficult when you have to scream over engine or generator noise during conversations or are left lying awake at night listening to the melodious hum of an air conditioning unit. Installing soundproofing can make a huge difference in onboard noise reduction. Here's how to transform the hullabaloo of your boat into the peace and tranquility of a floating Zen garden.

The best way to combat noise is by containing it at the source — within an engine compartment, for example. Soundproofing is perfect for this application, and while not fireproof, it is typically fire-retardant up to around 225 F.

Installation of a good quality foam soundproofing barrier can reduce engine noise by 10 to 35 decibels (about 65%). Soundproofing material is available in a wide variety of forms, from sprays and paints to foil-backed foam panels. Foam panels are a popular choice and one that's very effective against airborne noise pollution.

Soft sound shields, such as this one from GSI (stopthesound.com), provide both installation flexibility and significant noise reduction.

Self-adhesive panels are easy to install (just peel and stick), but you have to plan and position them exactly where you want them the first try as you typically can't reposition them without damaging the foam. Panels without adhesive backing require spray- or brush-on contact adhesives, which may allow a bit of last-minute repositioning, making them easier to work with in tight spaces.

­Regardless of adhesives used, overhead panels require additional support from mechanical fasteners.

Regardless of the adhesives used, panels also require the use of mechanical fasteners (such as screws and fender washers) particularly for overhead horizontal installations.

Soundproofing panels can be cut to shape with a box cutter or razor knife, however a serrated knife blade will provide a cleaner cut of the foam material itself. Thin sheets of soundproofing material can also be cut with a pair of good quality scissors. To ensure the best fit (and avoid cutting snafus) make cardboard templates first to check fit and for use as a cutting guide. Be sure to dry fit everything prior to applying adhesives or peeling self-adhesive panels.

Use joining tape to seal and prevent sound "leaks" at panel joints.

When planning your installation, remember that sound flows like water, meaning you'll want to use Mylar seal or joining tape (typically provided by the manufacturer) to prevent "leaks" at panel joints. Cables and hoses penetrating the material should be sealed using tight-fitting rubber grommets, while access hatches should close snugly with a good, tight seal.

That said, any soundproofing installation must provide adequate ventilation for the engine. Required vents and air holes can be quieted using air baffles. It's not realistic to expect all noise to be eliminated once soundproofing is installed, but when done correctly, you should be able to carry on a conversation at normal volume levels. After all, who wants to yell when you are trying to relax?

Soundproofing Installation Tips

• Read all instructions for the soundproofing, adhesives, and mounting hardware prior to starting your project.
• Make templates to check fit prior to cutting panels. Be sure to allow for material thickness at corners.
• Ensure your installation provides adequate ventilation and keeps insulation material above bilge water levels. (Avoid exposure to any wet areas.)
• Provide a minimum clearance of 6 inches between soundproofing and engine or generator exhaust manifolds.
• Use sharp tools when cutting soundproofing, both to produce clean cuts and to avoid tearing of reflective foil. The foil or silver facing side should face upward when cutting.
• Handle soundproofing material carefully. Avoid folding the material back on itself, which can result in creasing.
• Seal all exposed edges, joints, and corners with Mylar seam tape to prevent water or other contaminants (such as fumes or oil) from entering and degrading the soundproofing material. Seam tape can also be used to provide chafe protection at wear points. You can purchase it at most marine stores.
• Don't rely on adhesives alone. Use fasteners and fender washers where appropriate (all overhead and vertical surfaces) to ensure backup in the event of adhesive failure.
• Apply adhesive for and install one panel at a time. Install the top panel first, which lets adjacent vertical panels provide support to the outer edges of the top panel.

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Frank Lanier

Contributing Editor, BoatUS Magazine

Capt. Frank Lanier is a SAMS-accredited marine surveyor with over 40 years of experience in the marine and diving industries. He’s an author, public speaker, and multiple award-winning journalist whose articles on boat maintenance, repair, and seamanship appear regularly in numerous marine publications worldwide. Contact him via his YouTube channel “Everything Boats with Capt. Frank Lanier” or at captfklanier.com.

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BEST Marine Engine Noise Reduction Tips – Outboard Cowling / Inboard

I’m from the North American east coast, and I am very familiar with boating and boats in general. I grew up not far from the beach, and a lot of people has boats. One thing though is that some boat engine can be very loud. In this article, I will be explaining several methods for boat motor noise reduction.

How to reduce noise from a boat engine? Reduce noise from a boat engine by installing some sound dampening material into the cowling.  Self-adhesive butyl rubber anti-vibration membrane w/ aluminum layer is what I recommend.

Of course, this is just one solution in reducing boat engine noise. The method above is specifically for outboard engine noise reduction. There are other types of boat engine soundproofing methods I will be discussing.

Why Is Engine Bay Soundproofing Important?

Engine bay soundproofing is essential because “a quiet boat is a good boat.” That’s what my uncle used to tell me; it’s like a car when an older vehicle starts making noise you know the car is not in prime condition. A boat is the same because as boat ages, you will begin hearing more engine noise and more overall noises throughout the boat.

New boats are quiet, and when something like a boat or car is quiet while running means, they are well engineered, dependable and gives a comfortable ride.

I don’t know about you, but when I was on my families boat, I found it so relaxing to anchor somewhere to have a peaceful afternoon. The boat engine would be off for most of the time, but while cruising, we had a boat with an engine that made a terrible noise.

It was basically the noise of an engine but intensified ten times over. We couldn’t wait to get to where we wanted to go and shut it off to have some peace and quiet.

It was also a bit embarrassing traveling around the river with that noisy monstrosity. When I was younger we never really thought about soundproofing a boat engine, so my father eventually traded it for a newer model, like the majority of people would have done. I wish I would have had an article about engine bay soundproofing to show my father; I could have saved him a few dollars!

Health Benefits of Boating

The reason why I find it essential to soundproof a boat engine bay is that while you have a boat, you want to make it worth the hefty price you paid for it. If you’ve ever thought about buying your first boat, you’ve most likely heard the adage “The best days when having a boat, is the first day and the last day.”

The reason for that saying is apparent; you’re happy on the first day of having your new toy but so happy to finally get rid of the boat after you find out that it is not as relaxing and all its cracked up to be.

Let’s try to make your boat ownership the best decision you’ve made to have your summertime fun; by possibly fixing a significant noise problem that will cost you very little money and even less work.

Side Effects of Loud Engine Noise

The side effects of loud engine noise I am referring to is concerning your health. The sound of a boat engine can exceed well over a hundred decibels . If not adequately insulated the engine noise can negatively affect your hearing. 

The sound pressure is measured in decibels, and like the temperature scale, decibels can go below zero. Someone with terrific hearing could hear a sound at -15 decibels. You enter the danger zone when the noise is over 85 decibels. Above 85 decibels is when you can begin to suffer some severe damage to your hearing.

If your boat engine puts out a constant noise of over a hundred decibels, you will eventually begin to feel the effects of hearing loss.

Engine Compartment Insulation Material

If you’re looking for a used boat, you might want to consider adding some new sound absorbing material where noise persists. The reason for this is because the life expectancy of most sound absorbing material that is installed in boats today is approximately ten years.

Some people might get confused when they hear a ten-year-old boat making more noise than its five-year-old counterpart and think there is something wrong with the engine.

Before assuming that you need someone to tinker with the motor, take a look at the sound deadening material in the engine bay for any wear and tear. It might be time to rip out the old material and replace it with a fresh new sound deadening product.

After years of enduring moisture from either fresh water or salt water, the sound deadening material will lose its effectiveness as it breaks down. A few cracks here and there will make the engine noise easily pass through them and make for a loud voyage.

Vibrational Damage

Not only that but every year the boat is running, the vibrations from the boat will get more prominent; and will result in loosening bolts throughout the ship.

After the bolts have loosened to a certain extent, you will begin to hear more and more rattles and squeaks. These noises will make your boat sound older every year.

If you want to avoid your boat sounding old and loud, you will have to make sure the sound insulation material is kept in tip-top shape. The sound insulation material in the engine bay will not only reduce noise but will lessen the vibrations coming from the engine.

I see some individuals around the internet WRONGLY suggesting material that is not an appropriate certified marine grade product for use in the application you are intending. Fire and also water resistance are necessary. Get the right stuff or hire your dealer to perform the job. Engine rooms can be noisy, hot with a potential for fire.

Two Different Types of Boat Engine Noises

There are different types of noises that a boat engine will make. You will need to carefully inspect the current sound dampening material to see if there is damage and what you need to fix it.

Structural born Noise

Structural born noise is when the boat is physically vibrating and causing multiple squeaks and rattles due to loosening bolts and fastening. It is the actual impact of an object on a building element, in this case, it would be a boat.

In most cases structure born noises are the hardest to isolate versus airborne sound; because the sound waves are a result of both sides of a building material vibrating. The reason they are challenging to isolate is that there are usually multiple sources.

Luckily in the case of a boat, the structure-borne sound would typically come from the engine bay, and that makes it easier for us to mitigate.

Airborne Noise

Airborne noise is the sound waves that are transmitted through the atmosphere. In this specific case, the airborne noise would come from the engine and other areas of the marine craft.

You can reduce the amount of airborne noise by physically blocking the source of the noise with noise blocking material. You will not be able to block the engine noise completely, but you can bring it back to what it sounded like when the watercraft was new, or at least close to new.

Airborne and structural noise is almost always intertwined when the sound is loud enough. If the airborne noise is loud, it can cause a structure to vibrate causing structural noise and vise versa.

1 – Outboard Noise Reduction

While the majority of engines have a cover, it generally does little to minimize noise. This engine cover, called the cowling, is mainly inefficient regarding noise reduction unless you supplement it with something far better.

Consult your boat owners manual before removing the cowling.  The engine covers on marine crafts are usually very sturdy, but you could still do some internal damage if you’re not careful. You definitely do not want to have engine trouble in the future because of this DIY soundproofing project.

Now that you’ve removed the engine cover you’ll see if the sound dampening material shows signs of damage. You can either remove the old sound dampening material or place the new stuff on top.

If you place the new material on top of the worn one, you could be doubling the noise reduction effect; but you could also be defeating the purpose of adding new material if the old one creates gaps that will let noise bleed through.

One thing I need to point out is that this will not solve the noise problem for every situation. There could be other factors as to why the engine noise is unbearable that simple boat engine cover insulation will not fix.

Outboard Motor Cowling Insulation

The cowling is off, and now you’re wondering what kind of sound dampening insulation you should buy. Not all noise insulation are created equal.

You will need soundproofing insulation that is not only heat proof but waterproof also. There are some great insulation out there made for vehicles that are heat proof but not waterproof so make sure you read the label carefully if you’re buying this at your local hardware store.

The outboard motor cowling insulation I recommend is the  Stinger Road Kill product from Amazon. This stuff is waterproof, moisture proof and heat resistant.

This stuff works well in eliminating a broad spectrum of sound frequencies. The max loaded vinyl is very dense and also flexible and contains Barium Sulfate to increase its density.

Boat Motor Insulation Application

When installing the sound dampening material in the cowling make sure not to cover the air vents while covering as much surface as possible. There will be some noise coming from the air vents, but this is unavoidable. Make sure the material does not come into contact with any moving parts, mainly if you are sticking it over the existing cowling insulation.

I did see some people online suggest a placing a cowling cover, the covers you put over the cowling while traveling to avoid rock chips. These types of motor covers SHOULD NOT be in place while you’re cruising on the water. The cover is strictly for when you’re traveling on roads or when the boat is in storage and not in use.

Please do not believe everything you read online because some soundproofing websites have very misleading information. Wrong information could end up overheating the engine and cause significant damage.

Reducing Outboard Motor Noise With a DIY Muffler

I’ve done some research online and by talking to some boat owners about how to minimize outboard motor noise the DIY way. I came across something interesting. A boat owner built a simple muffler system using a PVC pipe. They call this an outboard motor silencer.

I have to confess that I have never built this or even seen it in real life, but know someone that swears by it. There is also a YouTube video explaining the process.

As the picture above shows is that all you need is a curved PVC pipe with a cap on the end. Drill a few holes in the pipe close to the end cap using the water column as a sound baffle. This design can comfortably accommodate multiple propeller exhaust sizes.

This method for reducing outboard motor noise has a few added benefits; by giving a consistent back pressure that is consistent with a normal operation of the outboard motor when it is submerged in the water. This will lead to a much smoother idle and a faster prime of the water pump and tell tale.

Having this attachment will slow your boat down, that is the side effects of having a cheap fix for a loud boat motor. Read some of the comments in the video below for an insight into how this method worked for some boaters.

Inboard Motor Noise Reduction

Inboard motors are much less of an issue when it comes to sound proofing because they are already pre-insulated. If you find that your inboard motor is noisy while the hatch is closed then there is most likely something wrong with the engine itself.

A noisy boat motor can still be a problem even with an inboard engine because there can be cracks in the noise dampening insulation.

All you should need for this small soundproofing project is some self-adhesive project is rubber insulation matting.  You can use the same insulation as I recommend for the outboard motor cowling insulation because of its heat resistance and the fact that it is also waterproof.

Make sure that when you’re sticking the sound insulation within the motor area that you do not block any air vents. If you block any of these vents, your engine will most likely overheat so watch out for that. It is usually common sense, but sometimes even I make simple mistakes when my mind is not in the right place.

Conclusion For Marine Engine Noise Reduction

Marine engine noise reduction can be an easy DIY project. Especially if you know what you’re doing and you use the recommended products. If after reading this article and looking through your owners manual you’re still unsure on how to reduce the noise of your boat motor then you should let a professional look after it to make sure its done right.

If you didn’t find what you were looking for in this article, then I recommend searching the Reddit forums for boat motor noise insulation. There should be a few people asking the question, and usually, the people responding are people that have first-hand experience on this type of issue.

Thank You for checking us out! Please leave us a comment below if you have something to add that we might have missed, we love hearing your input so we can better our content going forward.

Don’t forget to also check out our YouTube channel for some awesome soundproofing videos.

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Marine engines frequently produce noise levels as high as 110 decibels on the A-weighted scale (dB(A)), comparable to the loudness of a rock concert. Primarily, that noise concentrates in the low to mid-frequency, ranging from 125 Hertz (Hz) to 2,000 Hz, which includes the frequency range of many human speech sounds and underwater noises important for marine life. Effective marine soundproofing is essential to mitigate this noise and ensure a quieter and more environmentally friendly marine environment.

In addition, there is low-frequency structure vibration-related noise. This type of noise, which is caused by the engine and machinery vibrations resonating through the ship’s structure, further complicates how marine soundproofing can be achieved. Reducing noise in marine environments requires a multifaceted engineering approach. This approach must account for both the air-borne noise generated by the engines and the structure-borne noise that leads to vibrations.

Applying our unique 4-Fold Approach ® system, Megasorber engineers have successfully developed a range of marine soundproofing products to help reduce:

• engine room noise
• vibration noise from the hull & structures
• wave slapping noise.

Engine room noise reduction with marine soundproofing

1. lightweight option for marine soundproofing:, nrc up to 1.0, megasorber fm50 (or fm25) to line the engine room or engine enclosure;, fm50:  nrc 1.0;, fm25:  nrc 0.82.

Megasorber FM50 and Megasorber FM25 are inherently fire-resistant, exceptionally lightweight and highly effective. They have a non-combustible Soundmesh G8 facing, are splash-resistant to fluid, and are tough and durable.

The key marine soundproofing features of the Megasorber FM acoustic foam panels are demonstrated through the schematic drawings below:

Superior acoustic performance: Megasorber FM25 and FM50 are highly effective in absorbing engine noise. The graph below highlights the acoustic performance over the various frequencies.

The FM50 and FM25 provide excellent marine soundproofing absorption over engine noise frequencies. After installing Megasorber FM50, the typical noise reduction is up to 10 dB(A).

Learn more about how Soundmesh G8 boosts the acoustic performance of 25mm thick acoustic foam up to 54.5%.

2. Super-quiet option for Marine Soundproofing

Megasorber c50 and cm28.

Megasorber C50 and Megasorber CM28 are marine soundproofing absorber-barrier composites. They are designed to effectively absorb and block the air-borne noise, specifically at a frequency range of the marine engine noise.

Both feature a non-combustible Soundmesh G8 facing, are splash-resistant to fluid, and are tough and durable, as shown in the schematic drawings below:

Megasorber C50:  NRC 0.85;  Rw (STC) 28

Megasorber CM28:  NRC 0.80;  Rw (STC) 24

For more details on how Megasorber composites have been engineered to provide maximum soundproofing effect, please follow this link: Soundproofing Composites .

IMO compliance requirements

1. economic option for marine soundproofing, megasorber p50.

Megasorber P50 is specifically engineered to absorb noise from marine engines, achieving its highest sound absorption efficiency within the range of 250Hz to 2,000Hz. It stands out as one of the few sound-absorbing materials that comply with the International Maritime Organization (IMO) standards, ensuring its suitability for use in marine environments.

Sound absorption of Megasorber P series products

(Tested to AS ISO 354-2006 Acoustics: Measurement of sound absorption in a reverberation room)

2. Super-quiet option for marine soundproofing

Megasorber p50 + megasorber d14.

Megasorber D14 is engineered specifically to effectively mitigate low-frequency noise that is transmitted through the structure of a vessel, while Megasorber P50 is tailored to efficiently absorb noise that travels through the air, particularly noise emanating from marine engines. The Megasorber P series and the Megasorber D14 products both adhere to the IMO standards, ensuring they meet global regulatory requirements for marine noise reduction.

Reduction of a wave slapping noise and vibration noise

Marine soundproofing is crucial for ensuring a comfortable and quiet boating experience, especially in lightweight, aluminium boats where wave slapping noise can reach up to 95 dB(A).

The optimal solution is to apply Megasorber D14 or Megasorber DT2 to the hull, as these products are specifically engineered to effectively reduce structure-borne noise from wave impact.

Megasorber D14 is a 2mm thick, self-adhesive vibration-damping sheet that provides excellent vibration control for aluminium panels up to 4mm thick and steel panels up to 3mm thick. For optimal performance, two layers of Megasorber D14 are recommended for 6mm thick aluminium plates or 5mm thick steel plates.

Megasorber DT2 is a 3mm thick vibration-damping tile designed for thicker panels, effectively accommodating aluminium panels up to 12mm thick and steel panels up to 10mm thick. For optimal performance, we recommend sealing the edges with Megasorber A200 adhesive once installed.

Megasorber DIS8 is a customised designed 2mm thick vibration isolation and damping sheet with a double-sided self-adhesive feature. DIS8 is designed to be inserted between the substrate and a top metal plate, forming a constrained layer-damping system. The top plate is usually 1mm steel, 2mm aluminium plate or a marine grade ply.

Megasorber DIS8WH-DS is a customised designed 2mm thick vibration damping pad with glass fibre cloth on both sides. It is specially designed to be integrated during the Glass-fibre Reinforced Plastic (GFRP) wet layer process and provides excellent wave-slapping noise for GFRP composite boats.

Applications of Megasorber DIS8

The schematic drawing below illustrates how the Megasorber DIS8 is strategically positioned between the substrate and an 18mm marine ply, delivering superior vibration-damping and sound transmission loss.

Displayed below is the Megasorber DIS8 installed on the bulkhead, featuring a 2mm aluminum top plate. This setup enhances the overall structural integrity while providing exceptional soundproofing and vibration damping capabilities, ensuring a quieter and more stable marine soundproofing environment.

Estimated noise reduction with Megasorber damping treatment

After applying Megasorber damping treatment , noise reduction can reach up to 20dB(A) for large, freely suspended panels. Typically, depending on boat construction, the noise reduction ranges from 10 to 15 dB(A).

The video below demonstrates the effectiveness of Megasorber damping treatments on a 5mm thick steel plate and a 12mm thick aluminium plate, showcasing the noise reduction before and after the application.

Marine engine room soundproofing

Megasorber’s FM acoustic foam is inherently fire-resistant and perfectly suits the harsh environments of marine engine room soundproofing.

Megasorber CM28 and Megasorber C50 are the absorber-barrier marine soundproofing composites for superior sound insulation.

Essential marine soundproofing solutions

Marine soundproofing plays a critical role in enhancing the comfort and safety of maritime environments, addressing the challenge of reducing engine noise, vibration, and other operational sounds that can permeate through a vessel’s structure.

With Megasorber’s advanced materials and technologies, such as acoustic foams and barrier composites, employed to absorb sound and prevent its transmission, vessels can effectively create a quieter atmosphere for both crew and passengers.

Soundproofing projects

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Melbourne Airport T4 Terminal

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Terminal 4 bus bay Melbourne airport

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• Soundproofing Simplified: Learn to soundproof like a pro

Boat Engine Compartment Insulation

Boat engine compartment insulation guide.

Author: Eric Zuck

Last Updated: February 9, 2024

Read Time: 10 Minutes

Last Updated:

February 9, 2024

Updated: Feb. 9, 2024

Table of Contents

•   Popular Boat Soundproofing Materials
•   Our Boat Kit in Action!
•   Why Soundproof a Boat Engine Compartment?
•   Sound Deadener
•   Insulation
•   How to Soundproof a Boat Engine Compartment
•   Featured Product: Boat Engine Compartment Insulation Kit
•   Get Help From a Second Skin Expert

The engine is the number one cause of noise on a boat and is made worse with the addition of wind noise and vibrational noise from water hitting the hull. All of these noises add up to make it difficult to have a conversation with your friends and family, or even to just relax.

While the latter two are more "part of the experience", soundproofing and insulating the engine bay compartment is easy, and it's a great way to turn the noise down so you can truly enjoy your boat the way it was intended.

Popular Boat Soundproofing Materials

Learn how adam got a 10 db reduction by using second skin in his boat engine compartment, second skin case study: boat soundproofing.

Damplifier Pro™

Heat Wave Pro™

"it's much quieter than before at idle/sunset cruise speeds making it easier to talk.", want great results like adam.

The Benefit of Marine Engine Compartment Insulation

A 2017 study by Wakefield Research (according to BoatUS Magazine ) found that 4 in 5 Americans say being around the water relaxes them . Scientists then found that even just looking at water “can trigger feelings of wellness, compassion, empathy, and happiness.” BoatUS Magazine seems like they may be pretty pro-boat, but we’ll take them at their word on this one.

An overly-noisy boat engine can unravel that relaxation in a hurry. A boat engine is typically only about 60-65 decibels when idling, but quickly ramps up to around 80 decibels of noise at cruising speeds and over 100 decibels at full-throttle for some boats. To put those noise levels in perspective, normal conversations can be heard with 70 decibels of background noise. At 85 decibels, you have to shout. And then at 100 decibels of background noise, you have to stand right next to each other AND shout to even have a chance.

Studies show that continuous exposure to more than 80 decibels of noise can cause n ausea, f atigue, i ncreased blood pressure, and i nsomnia. When you insulate your boat’s engine and create a more pleasant ride, you make it easier to do the very thing you bought the boat to do: relax.

This is me in my boat... someday.

Four Benefits of a Quieter Boat Engine

• More relaxing and more enjoyable rides
• Healthier rides due to reduced noise pollution
• Safer rides due to less distraction/inability to hear other boats.
• More legal rides if you need to comply with your state’s boating noise laws

When you’re out boating with the family and friends on your local lake or on the open water, why would you willingly subject yourself to those noisy conditions if you don’t have to? Let’s just nip in the bud right now so we can all relax and enjoy ourselves.

Choosing the Right Materials for Soundproofing and Insulating your Boat

Boats put out a lot of noise that can be hard to manage without the proper soundproofing materials and information. It's broken down to airborne noise and structural noise.

• Learn About Airborne Noise
• Learn About Structural Noise
• Most boat-related noises are airborne noises.
• The engine compartment needs to be as airtight as possible. Sound behaves like water. If you can look at your engine compartment, and see clear openings - those must be addressed first. If you don't... you basically have a hole in your boat, and decided to invest in a fancy water pump to remove the water instead of plugging the hole. A well-designed engine compartment should cut the sound you hear from an engine putting out 100 dBs to 70-80 dBs.
• Add sound insulation material to the hard-surfaces of the compartment. Hard surfaces reflect sound waves. By absorbing echos, there's less sound pressure inside your engine compartment AND less sound escaping the walls. By adding sound absorbing and soundproofing materials to all the hard, reflecting surfaces in your compartment, you can cut the noise level by 6-10 dBs.
• While often secondary to airborne noise issues, boat structural noise can be a big deal.
• A vibrational   sound deadener is most impactful if you have a smaller doghouse. Adding it to the underside of the engine compartment is an added bonus. By adding sound deadener to 100% of the compartment, you'll increase the density of the compartment as a barrier while also damping structural vibrations.
• Our testing shows using a vibration damper is most impactful if you have a smaller doghouse , because the tighter compartment construction tends to transmit more structural vibrations.
• For a larger engine compartment where you have more airspace and the engine is mounted, the vibration damping material will be most effective close to where the engine is mounted, although we often see people add damping material to the underside of the lid.

Choosing the right sound deadener

The best sound deadening product for a boat engine compartment is Damplifier Pro™ Sound Deadening Mats . Most boat owners go with Damplifier Pro™ for it's ease of use — just peel and stick. We recommend 100% coverage as an added layer of thermal protection. Make sure to seal the edges with foil tape to protect the material.

Applying Damplifier Pro™ will stop the compartment from rattling and transmitting structural noise, while modestly increasing the amount of noise blocked (more noticeable for lighter compartments).

Alternative: Spectrum™ Liquid Deadener

Spectrum™ Liquid Deadener is a popular choice for metal boat engine rooms and any part of the boat experiencing heavy vibrations (like around a generator). Spectrum™ is a high heat viscoelastic polymer that sticks extremely well to a cleaned metal surface, and is easily applied with a spray gun, brush, or roller for a seamless, waterproof and rust-proof finish.

If you have a fiberglass surface, a self-etching primer is needed for Spectrum™ to "bite" in. We would recommend Damplifier Pro™ instead.

Add Hand Roller

Choosing the right Insulation

Picking an insulation for your boat doesn't need to be complicated. We've done the research so you can enjoy the results! Both of our insulation choices have a foil backing, making it great for radiant heat AND great at absorbing the lower frequencies that engines give off!

Mega Block™ Hydrophobic Foam Heat Shield

If your engine compartment is mostly flat surfaces , Mega Block™ Hydrophobic Heat Shield is our go-to boat engine insulation! It's an open cell hydrophobic melamine foam covered by a 1000 ° F heat shield, which allows you to install it with only a 2" air gap from the engine. We've combine Damplifier Pro™ and Mega Block™ together in our Boat Insulation Kits .

Our peel and stick Mega Zorbe™ Hydrophobic Melamine Foam is our top-of-the-line, aerospace grade, sound absorber and heat insulator (just without the heat shield). This is a great way to add some absorption at the higher frequencies for larger engine compartments . Just be sure to leave at least a 6" gap between this and the heat source.

Heat Wave Pro™ Jute Insulation

If your engine compartment is mostly curved surfaces , Heat Wave Pro™ is extremely flexible sound insulation and automotive heat insulation that can fit those contours. These all natural fibers (no itch) are treated to be water resistant (no mold or mildew) and durable. Two things to note about Heat Wave Pro™ is that it should be installed at least two inches away from the heat source and its edges should always be taped with foil insulation tape in marine applications. Heat Wave Pro™ and Damplifier Pro™ can be paired together in our Boat Insulation Kits , as well.

Keep your boat's engine noise below deck!

How to Soundproof and Insulate a Boat Engine Compartment

We're just about ready to give you the ultimate soundproof and insulated boat engine compartment one can get. Are you ready?

Steps to Soundproof & Insulate a Boat Engine Compartment

• Clean the Surface - Remove any old insulation to expose the metal (or fiberglass). Then, use denatured alcohol to clean off any rust or dirt.
• Add Sound Deadener - Completely cover the boat engine compartment with Damplifier Pro™.
• Add the Insulation - Your second layer is Heat Wave Pro™ or Mega Block™, to add insulation and sound absorption. Mega Block™ for the straighter surfaces and Heat Wave Pro™ for the curved surfaces.
• Seal the Seams - Tape any seams with foil tape to protect edges and seams.
• Get out on the Water - Get that boat back out on the water! That's the smile of a man with a quiet boat!! :)

Boat... Meet Insulation. Insulation... This is Boat. You're Gonna Be Friends.

Your boat and this insulation are going to be best friends... they just don't know it yet. Get ready to introduce them. And introduce yourself to the peace of mind that comes from knowing you'll have the quietest boat at the dock.

• Damplifier Pro™ ends that vibrational noise from the fiberglass housing.
• Mega Block™ for the straight surfaces
• Heat Wave Pro™ for the curves

Closing Thoughts

Insulating your boat’s engine compartment is relatively simple and should take you no more than a few hours. No matter what materials you choose, remember to leave adequate ventilation and be careful not to cover any exhaust vents. As you know, on a boat, water gets everywhere.

The good news is you have options depending on your type of boat and your goals. Let us know if we can help you figure out the combination that works best for you, whether it’s thermal insulation or noise blocking.. And when you’ve completed your project, send us pics and helpful tips so we can continue improving our guides and get your boat featured on our boat soundproofing customer projects page !

If you have any other problems with automotive or home soundproofing, check out our many other recommended posts! We have advice on how to reduce air conditioning noise , soundproof a room or office, and many more!

Have questions about your project?

Call us at 1.800.679.8511

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Soundown and Hough Put a Lid on Engine Noise

Tests of 10 sound-attenuation products find the best are also the most expensive, with a few notable exceptions..

Engines make noise. Crew-especially when theyre trying to hold a conversation, sleep, or just relax-don’t like noise. The solution? Isolate the crew from the engine noise and vibration. In this update of our May 1, 1993 report, 10 sound-attenuating products are tested and ranked.

Noise and vibration are inseparable. Noise exists because vibration causes variations in the air pressure that reaches the ear. This is perceived as sound. An effective control deals with both the vibration and the airborne noise.

Noise levels are measured in decibel units, usually referred to as dBA (the A denoting that the measurement is adjusted for the frequency response of the human ear, rather than the total sound level energy). Everyday sounds fall into a range from roughly 25 dBA (a suburban bedroom at night) to 100 dBA (a chain saw at a distance of 3).

A sensitive ear can distinguish differences of 1 dBA, but it takes a 5-dBA difference to be noticeable. On a boat, an unshielded diesel genset will produce sound levels of 100 dBA at 3; an inboard typically raises the noise in the engine room to about 110 dBA. The object is to drop those levels to approximately 75 dBA for more-or-less normal conversation, and another 20 dBA for comfortable sleeping with the engine running.

There are three basic approaches to making your boat quieter. The first step is to use flexible mounts to isolate the vibrating machinery from the hull. These help prevent the transmission of vibration through the solid structure of the boat, and the consequent reverberation of hull sections that can act like amplifiers. Correcting any engine-shaft misalignment will certainly help.

The next step is to surround the noise-producing machinery in a tight, insulated enclosure to reduce air-transmitted noise.

The final step is to line enclosed living quarters, such as cabins, with sound-absorbent materials.

Once youve reduced vibration-and the associated structure-transmitted noise-youre ready to deal with airborne noise. The first step is to enclose the noise-generating components-the engine-in some sort of box or compartment. Almost any sort of enclosure will reduce noise levels by 5 to 10 dBA, but improving on that takes an understanding of the nature of noise.

There are only three things that can be done with the air vibrations that we regard as noise. They can be reflected, transmitted or absorbed. Transmission doesn’t do us any good in terms of noise reduction. The 5-10 dBA reduction that comes from putting the engine in a box is due almost entirely to the sound energy absorbed by the box; most of the noise is transmitted right through the boxs walls. Reflection may have some value in some situations, but reflecting sound waves back into an enclosure simply makes it noisier inside the enclosure. A reflective material works when theres somewhere to reflect the sound.

Sound, after all, is a form of energy, and you can’t just make it vanish. You can, however, convert sound energy into another form of energy-heat. The energy dissipates when the absorbent material becomes displaced or compressed.

The amount of energy absorbed depends upon the mass (or weight) of the material, how far its displaced or compressed, and the materials damping capability. Materials like lightweight foams and fiberglass wool have good damping but not enough mass to be effective by themselves. They have a role in dealing with noise, insofar as they can reduce reflection. More specialized sound-absorbers are more effective. These are composite materials with a high-mass layer, one or more damping layers, and (usually) a thin plastic film at each face to protect the damping layer(s) from mechanical damage and moisture.

The high-mass layer should be heavy, limp, and nonporous. It should also be as thin as possible, simply because space aboard is usually at a premium. A sheet of lead works best, but a lead-filled sheet of plastic can be used where a physically tougher material is required. Mass layers of lead typically weigh 1-2 lbs. per square foot; lead-filled plastic weighs about half that for an equivalent thickness.

On either side of the mass layer is a layer of foam or fiberglass mat. The layer facing the noise source is called the absorption layer; its function is to damp out the vibrations caused by the movement of the mass layer. On the other side of the mass layer is an outer layer of foam or fiberglass: the decoupling layer. It isolates the heavy layer from the engines enclosure.

The range of frequencies that a sound-isolation material can deal with effectively varies with the product of the square root of the weight of the mass layer and the thickness of the decoupling layer. Thus, a 1-lb. per sq. ft. barrier on a 1/4″ decoupler might only be effective in dealing with high-pitched sounds (500 Hz and higher); doubling both the weight and the thickness extends the useful frequency range to 125 Hz.

Reductions in dB are additive. Lets say an unshielded engine produces a noise level of 110 dBA. If we build a box from 5/8″ plywood around the engine, wed lower the sound level (measured at 1′) to roughly 100 dBA, assuming that the box doesn’t leak and that all openings are taped. If the vent openings to the box lead overboard rather than into the cabin, you can reduce noise by another 15 dBA or so. Make sure that your vent ducts are baffled, or make up a labyrinth with several 90-degree turns.

If you line the box and the vent ducting with a simple absorption layer of fiberglass or foam, youd only lower the noise level outside the box by 5 dBA or so, even if you used a thick layer of sound-absorber. If you lined the box with a composite material (1-lb./sq. ft. mass layer, 2″ thick overall), youd get the noise level 2′ from the box down to a bearable 76-78 dB, or 61-63 dBA if the engines air vents are ducted overboard.

The actual noise level in the cabin will depend on the distance between the engine box and the cabin; sound levels drop by 6 dBA each time you double the distance from the source. If the berths are close to the engine, you can also apply absorbent material to the cabin ceiling and walls (1/2″ to 1 foam-backed fabric and perforated vinyl headliners are popular choices). If you find that noise is coming up through the floor, try noise-absorbing carpet. As a bonus, these materials are also good thermal insulators.

The Materials We asked four major manufacturers of sound-control products for their recommendations. While there are other products available, we believe the selections discussed in this report nicely cover the range of products.

In all, 10 different products were tested, ranging from 1/4″-thick fiberglass sheets to plywood with a built-in sound-deadening layer to 2″-thick foam/lead/foam composites. For comparison purposes, we also included exterior grade plywood, which is typically used for engine enclosures.

The Tests Not all noise is equal. Its much easier to block high-pitched (high frequency) sounds than low-pitched ones. So its not too meaningful to attach a single number to a sound-deadeners effectiveness without specifying the nature of the sound. A common method of evaluating a soundproofing material is to conduct a series of tests at different sound frequencies and plot on a graph the percentage of sound reduction at each frequency.

We took a more direct, if less sophisticated approach. The noise produced by an engine is a non-uniform mix of frequencies covering the entire audible spectrum, from very low to very high frequencies. Rather than trying to analyze the composition of that noise, we used high-fidelity sound equipment to record the noises produced by an eight-cylinder gasoline engine and a four-cylinder diesel. For the purposes of our tests, our engine was a three-element loudspeaker system (woofer, mid-range, and tweeter) in a 14 x 14 x 24 enclosure. This allowed us to dial in any desired noise level.

Our engine room consisted of a plywood box, 2′ x 2′ x 3′, with all openings sealed or gasketed to avoid sound leaks (venting wasnt a consideration). We used a Simpson dB meter to measure sound levels. The amplifiers controls were set to produce a sound level inside the engine room that corresponded to the sound levels produced by the engines themselves: 115 dBA for the gas engine and 110 dBA for the smaller diesel. Sound outside the enclosure was measured at a distance of 2 from the speaker.

We tested the sound-deadening plywood by replacing the engine room with a new box made of the plywood under test. All of the other products were evaluated for noise-reduction by installing them, one at a time, as a liner for the plywood box.

In addition to our tests on sound-deadening effectiveness, we evaluated each products ease of cutting and installation, and its resistance to gasoline, diesel fuel, motor oil, antifreeze, and water.

The Findings Our first tests confirmed what we had known all along: Simply enclosing the engine in a plywood box reduced the noise level outside the box but raised it considerably inside the enclosure. Our gas engine, with no enclosure, produced sound of 90 dBA. With the speaker placed in the box, we measured a sound level of 72 dBA 2′ away. At the same time, the noise level inside the box increased to 115 dBA. We found similar results with the diesel recording.

The effective reduction in dBA we observed with the products tested is shown on the chart above. Not surprisingly, we found that the thicker and heavier the sound-control product was, the more effectively it worked. Generally, the effectiveness of the products was comparable regardless of which engine was used, though we did find somewhat more effective sound-reduction from the diesel than the gas. This was due to the fact that the diesel engines noise consisted of more high-frequency components. A few products, such as Soundcoat Soundmat, were noticeably better at dealing with the diesel engines noise; the chart lists both numbers.

The products fell into three groups, based on their effectiveness. The three groups generally carried prices that corresponded with their performance. The most effective products tended to be the most expensive, although there were some notable exceptions. The most effective products gave a 12-15 dBA noise reduction, the least effective about 3-5 dBA.

None of the products showed any signs of degradation after several days of exposure to any of the liquids we applied to them. All were easy to work with and apply; the foam products were physically stronger than the fiberglass ones and could be glued, which gave them an advantage. On the other hand, the fiberglass products can withstand much higher temperatures than the foams and are all flame-resistant (although the facing material on some may support combustion). All the foams burned when exposed to a flame.

Here’s our product-by-product evaluation:

Greenwood dB-Ply Greenwood dB-Ply is a sound-absorbing plywood. Its not intended to be installed in an existing enclosure. The sample tested consisted of two layers of three-ply fir plywood making a 1/2″ sandwich ; the core or filling was a resilient plastic material. Compared to conventional plywood of the same thickness, dB-Ply was about 5 oz. heavier per square foot. It can be sawed, drilled, nailed, or glued just like conventional plywood.

Bottom Line: Greenwood dB-Ply, compared to conventional plywood, offers a modest but real reduction in transmitted sound (4 dBA decrease in sound level is equal to a 25% reduction in perceived noise). The 1/2″ thickness lists for $3.03 per sq. ft., which makes it pricier than exterior grade fir plywood. If youre building a new engine enclosure, or replacing a deck that happens to be noisy, dB-Ply is a good choice.

Greenwood FGSA-SR FGSA-SR is a rigid self-supporting sound absorber with a fiberglass core covered on both faces with reinforced aluminum foil. A 1/4″ panel weighs only about 4 oz. per sq. ft. In terms of pure sound-absorption, its one of the least-effective products tested, even when mounted (as per instructions) on spacers that supported it 1″ in from the enclosure wall. FGSA-SR is easy to cut with a sharp knife.

Bottom Line: At $3.75 per square foot, FGSA-SR is moderately priced and moderately successful as a sound barrier. It can be useful when demands are light, and its light weight and rigidity are desirable features.

Hough Marine: Acoustical Fiberglass This product is 1″-thick fiberglass covered with a scrim-reinforced, white-painted aluminum foil on one side. Its a moderately effective barrier, and, at $1.30 per sq. ft., its the lowest-priced product we tested. Like the other fiberglass products, its flame-retardant. It weighs 4-1/2 oz. per sq. ft.

Bottom Line: Hough Acoustical Fiberglass is hard to beat when your requirements arent severe. Its inexpensive, lightweight and easy to use. Its fastened to the interior of an enclosure with nails or screws.

Hough Marine: Acoustical Foam 100 Houghs Marine Acoustical Foam can be thought of as the foam equivalent of their Acoustical Fiberglass. Its 1″ thick and has a metalized plastic facing on one surface. Its extremely lightweight-less than 4 ounces per sq. ft. It cuts easily, and can be fastened with glue, screws, or nails. Sound attenuation was the same as for Hough Acoustical Fiberglass-moderately good. Its not fire retardant.

Bottom Line: Hough Marine Acoustical Foam 100 is a bit more versatile than Acoustical Fiberglass in that you can glue it with a structural adhesive. Theres a price for this convenience, however. At $2.61 per sq. ft., its about twice the cost of the Acoustical Fiberglass but provides only comparable noise reduction. This is one instance in which high cost isn’t best.

Soundcoat Soundfoam w/ Tedlar Soundfoam with Tedlar consists of a sheet of foam with a plastic film on one face. Its available in thicknesses ranging from 1/2″ to 2″. We tested the 1″ thickness. This is the lightest product tested-only 2-3/4 oz. per sq. ft. Its also among the most expensive of the group of moderately effective products ($3.48 per sq. ft.). It cuts and mounts easily, using glue, nails, or screws. Its not fire retardant.

Bottom Line: Soundfoam with Tedlar performed comparably (though a trifle less effectively) than Hough Acoustical Foam 100, at a 33% higher cost. We don’t see any reason to pick it over either Houghs Acoustical Foam or Acoustical Fiberglass.

Soundcoat Soundmat LFM Soundmat LFM was the least effective and most expensive of the three-layer composites tested, falling into last place in the moderately effective group. It was outperformed by three single-layer products with prices ranging from $1.30 to $3.48 per square foot. Soundmat LFM lists for a staggering $8.89.

Bottom Line: Dont bother.

Hough Marine Barrier 104 While it headed the group of moderately effective products, Hough Marine Barrier 104 was only slightly more effective than its Acoustical Fiberglass or Acoustical Foam. This was surprising, because Marine Barrier 104 is a three-layer composite, featuring a filled-vinyl layer between two foam layers.

We suspect that its relatively weak performance is due to its very thin (1/4″) decoupling layer.

Bottom Line: Marine Barrier doesn’t offer enough improvement over the same companys Acoustical Fiberglass to justify the additional weight (1.21 vs. 0.28 pounds per sq. ft.) or price ($5 vs. $1.30 per sq. ft.).

Soundown 2″ Lead/Fiberglass Soundowns 2″ Lead/Fiberglass is one of the three products that made up the top performance group. Its a three-layer composite, with a layer of lead between two 1″ fiberglass bats with a scrim-reinforced metalized-plastic layer on the inner facing. We observed a 12-dBA reduction in noise with the gas engine and 14 dBA with our diesel. Like the other fiberglass products, it can’t be glued in place, but cutting and installation are easy. Its fire retardant.

Bottom Line: An effective sound barrier product. Recommended.

Hough Sonovinyl Supreme Sonovinyl Supreme had test numbers identical to Soundowns 2″ Lead/ Fiberglass composite. Its marginally heavier (1.52 vs. 1.38 lbs. per sq. ft.) and slightly less expensive ($6.44 vs. $6.77 per sq. ft.). Construction is also similar to the Soundown product, except that Sonovinyl Supreme uses a filled-vinyl layer instead of a lead layer.

Soundown 2″ Lead Foam This product is essentially the same as Soundowns 2″ Lead/Fiberglass, with foam replacing the fiberglass. It was the most effective (by a hair), producing the same 12-dBA reduction in noise from the gas engine as Soundowns 2″ Lead/Fiberglass and Houghs Sonovinyl Supreme, and a 1-dBA greater reduction (15 dBA) for the diesel noise. Its advantages are slightly easier installation (it can be glued) and better performance. Its comparative disadvantages are lack of fire retardance, increased weight-at 1.61 lbs. per sq. ft., its the heaviest product tested-and higher cost ($7.19 per sq. ft.).

Conclusions/Recommendations The most effective sound barriers were three 2″-thick composites-Soundown 2″ Lead/Foam, Soundown 2″ Lead/Fiberglass, and Hough Marine Sonovinyl Supreme. Any one of these products should do a good job of suppressing noise at its source.

If all youre looking for is the maximum in noise control, Soundown 1″ Lead/Foam is your choice, though not by much. Hough Marines Sonovinyl Supreme performed as well for a gas engine, almost as well for diesel, and costs less. If youre concerned about fire protection, Soundown 2″ Lead/Fiberglass will provide comparable performance combined with fire retardance at a comparable price. You wont be able to glue it, however.

If all you need is a sound barrier for quieting a cabin or the like, Hough Marine Acoustical Fiberglass is effective and inexpensive. And if youre starting from scratch, Greenwoods dB-Ply is a good choice.

Many older boats may not have fire retardant engine box insulation. Installing a quality product is neither terribly difficult nor expensive. Its a good upgrade project.

Contacts- Greenwood Forest Products, 25895 S.E. 72 Ave. Suite 200, Portland, OR 97224; 800/333-3898. Hough Marine and Machine Co., Inc., 1111 NW Ballard Way, Seattle, WA 98107; 800/423-3509. Soundcoat Co., Inc., 1 Burt Dr., Deer Park, NY 11729; 516/242-2200. Soundown Corp., 17 Lime St., Marblehead, MA 01945; 800/359-1036.

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Marine Insulation…

With 36 years of experience of producing acoustic materials for Soundproofing and Noise reduction, we have the perfect solution for your marine acoustic problems. Our marine insulation products are ideal for sound-proofing boat engine rooms and controlling noise and vibration problems. Acoustafoam’s Class O composite products offer the best possible acoustic result especially for engine room sound insulation due to the multi-layer combination.

Acoustafoam laminates are used in many industrial applications but mostly used for the marine industry engine room noise problem areas.

Acoustafoam Laminates have three layers in addition to a protective facing for cosmetic and practical functions:

The Absorption Layer

A thick layer of 25mm fire zero rated Class O foam which soaks up noise and stops it bouncing around the engine compartment.

The Transmission Layer

A high-density 5kg per square metre polymeric barrier that provides the highest possible mass for the job of transmission loss (stops noise from getting through to other areas of the boat at the application wall).

The Isolation Layer

This 6mm layer of foam has a crucial function, it acts like the gap in double glazing and stops the noise that hits the transmission layer being carried through to the bulkhead.

Acoustafoam Marine Laminates can be supplied with a range of facings. PU Films Black and White, Glass Fibre, Aluminium Coated Glass Fibre, Aluminium Foil, Fire Rated Fabrics or a range of Sprayed Fire Rated Paints.

Acoustafoam offers a standard variety of products for marine insulation applications. Sheets 990mm x 590mm x 32mm – 4 sheets per box with a self-adhesive backing. Installation is easy. Simply cut the material to shape, peel off the release paper and fix to the affected area. Use Acoustafoam jointing tape to seal butt joint edges.

Acoustafoam manufactures marine acoustic insulation made from Rockwool fire pro. RW2000 is a rock mineral wool slab engineered to provide A-rated fire protection aboard ships and offshore installations. This product is Lloyd Register of Shipping and MED certified A30 and A60 fire protection to steel decks and bulkheads. It can be used to provide fire protection, thermal insulation and sound reduction with the minimum of weight. The product is laminated with B67 foil coated glass Class O fire rated.

Material code: RW 2000. Description : Marine Rockwool Colour: Foil faced (B67) Sheet size: 1000mm x 600mm.Thickness: 25mm – 40mm – 75mm. Thermal conductivity: 0.033 w/mk at 10*c.

Acoustics: Marine Rockwool foil faced slabs can considerably reduce the level of environmental sound.
Fire specification: RW 2000 is Lloyd’s Register of Shipping certified, and MED approved to provide A30 / A60 fire protection.

Applications: Fire protection, thermal insulation and acoustic treatment of marine and offshore installations.
Finishes: The sheets can be supplied with a factory laminated reinforced foil facing. The foil is intended as a vapour barrier, and butt joints should be sealed with foil tape (b67/50mm/s.a.).

Fixing: Contact adhesive, Mechanical fasteners and Self-adhesive backing if required. Work on the site: Fit to clean, dry surface sheets of pre-cut shapes. All but joints cover with self-adhesive 50mm b67 foil tape. Sheets can be cut using a sharp knife. This product is also supplied with pre-cut shapes and edges material wrapped.

We’re Waiting To Help You

Therefore, get in touch with us today and let’s help your business acoustic solutions.

We are the founding company of the Acousta group. We specialise in the manufacturing of foam, rubber and plastic components for a wide variety of sectors. The components are processed from blocks, sheets and rolls of materials using our band saws, CNC machines and water jets to our customer’s specification.

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Quieting Your Boat’s Engine

• By Roger Hughes
• Updated: June 27, 2024

The engine in my 1977 Down East 45 schooner, Britannia , is a tried and trusted — but noisy — Perkins 4-236, an 85-horsepower four-­cylinder diesel. There are also a Kubota three-cylinder diesel generator, five electric pumps and two bilge air blowers, all under the cabin sole.

I call the space the equipment bay. It runs 12 feet under the saloon floorboards and is 3 feet wide at the sole level, then tapers to just 15 inches at the bottom of the 41⁄2-foot-deep bilge. Seven removable floorboards give amazing access to all the equipment below, but the large space also acts as a massive boombox.

I previously had restored the teak-and-holly sole to its original beauty throughout the whole boat, but this made no difference to the noise level from the machinery below. When both diesels and extractor blowers were running, it was very noisy in the saloon, with a dull drumming you could almost feel. So I decided to do something about it.

There are a number of products that claim to significantly reduce noise from machinery, and some are specifically designed for boats. The trouble with most of these is they are also specifically aimed at your bank balance! For a boat my size, I found prices ranging from $350 for simple ¾-inch foam to $800 or more for double-thickness sound-­insulation sandwiches.

In simple terms, the object of sound insulation is to absorb noise at its source, and thereby minimize what filters into the interior of the boat. It would be practically impossible to eliminate this altogether, but I had effectively reduced the engine noise from a similar diesel on a previous boat simply by installing a false floor beneath the cabin sole. This is quite an easy and inexpensive do-it-yourself way to achieve a significant increase in peace and quiet.

Before I started work on Britannia, I wanted to take a reading of the sound levels to have a numerical comparison after the modifications were complete. I downloaded a neat iPhone app, a decibel meter by Decibel Meter Pro, for the vast sum of 99 cents, from iTunes. It was very easy to use, and I took readings at head height in the center of the saloon. With the main engine running at cruising speed, the meter registered 85 db. Then I started the generator as well, along with the twin extractor fans. The level went up to 93 db, which is roughly equivalent to a power lawn mower. When the freshwater pump was activated, it added another few decibels. I don’t know how accurate these readings actually are, but it doesn’t really matter because what I wanted was a comparison of before and after sound levels.

Fitting the False Floor

To get started, it was first necessary to make support battens for the false floor panels to lie in, under the existing plywood sole. I bought a 24-by-48-inch sheet of ½-inch plywood and cut it into 4-inch-wide strips with my table saw. I also made ¾-inch square battens out of hardwood. It was necessary to reposition some pieces of equipment fastened to the sides of the floor beams, such as wire hangers, water pipes and the big main engine filter. They all needed to be lower than the new floor. The 4-inch-wide plywood strips were then screwed to the underside of the 2-inch-wide floor beams, forming a 1-inch lip on either side.

I screwed the ¾-inch square battens to the sides of each aperture to support the ends of the false floors. I painted the beams and all the new timbers white.

I found some medium-­density fiberboard (MDF) at Home Depot that cost $25.95 for an 8-by-4-foot ½-inch sheet. I calculated that I’d need two to make the seven false floors. MDF is a heavy manufactured board similar to particleboard but smooth on both sides, with a density of 44 pounds per cubic foot. It’s used to make stereo-speaker boxes and other things for which sound control is required.

The sound-deadening properties of a ½-inch-thick sheet are actually better than the ¾-inch-thick marine plywood sole, which is roughly 35 pounds per cubic foot. (The MDF sheets were also available in ¾-inch thickness but would have been heavier and more expensive. In the end, I decided to compromise between weight, density and price, and go for the thinner stock.)

One problem to be aware of with this type of manufactured boards is their susceptibility to deterioration in damp conditions. If there is a chance they might become wet, it would be better to use marine plywood, though it’s much more expensive. A store employee cut the MDF sheets to the sizes I needed using a vertical circular saw. This saved me having to manhandle them out to the car, and enabled them to fit in my vehicle. I had them cut half an inch smaller than the spaces between the individual beams to prevent them jamming when I needed to lift them out to gain access to the bilge. A few boards still needed trimming to fit round obstructions that I could not reposition, but that was easy to do with my jigsaw.

The simplest, time-­honored method to handle boards covering apertures is to cut a hole in the board big enough to get a couple of fingers through to lift it in and out. But these MDF boards were too big and heavy for that, and it would also have allowed a little bit more noise and heat to escape. I therefore drilled 3⁄8-inch holes in each board and threaded some 3⁄8-inch-diameter rope through them, knotting it on the underside to form simple handles to easily lift the boards in and out.

The weight of the new fiberboards was 60 pounds, but it’s all positioned low in the hull, and it was a small price to pay for reducing the noise. When lying between the beams, their weight also keeps them firmly in place. The sole and subfloor now has a combined thickness of 1¼ inches, with a density of about 80 pounds per cubic foot.

Beat the Heat

To complete the project, there was one more thing I wanted to do. We could often feel heat permeating through the single-­thickness cabin sole when either of the diesel engines had been running a long time, especially on our own soles when walking barefoot. There must have been some sort of insulation glued to the underside of the floorboards at one time, but this had disintegrated. What was left was a dirty layer of dry adhesive that had to be scraped off by hand using Goof Off adhesive remover and a sharp 1½-inch chisel. I then painted the underside of the floorboards white.

To reduce the heat, I decided to add a layer of thermal insulation in the space between the subfloor and sole.

I bought two 4-by-8-foot sheets of Rmax Thermasheath R6 foam-board insulation from Lowe’s for $21.98 each. These are 2 inches thick, with aluminum foil on one face and an insulation rating of R6, which is the highest available for this thickness of foam. I cut them to the sizes I needed at the store using a sharp knife, which helped me fit them in my car. I then glued them to the underneath of each plywood floorboard using cheap construction adhesive by Liquid Nails; it was only $1.95 for a 10-ounce caulking-gun cartridge. This adhesive does not melt the foam.

The section of floor around the Perkins engine was particularly awkward because parts of the top of the engine were higher than the bottom of the floor beams. In fact, the valve cover was only an inch below the sole. This was, of course, the principal source of all the noise, so it needed special attention anyway.

I fitted battens all around the engine as I had in all the other openings, then shaped pieces of fiberboard to fit around the engine as well.

Next I cut pieces of foam and fiberboard to the size of the aperture and pressed the foam down over the engine with the fiberboard on top by actually standing on them. This indented the soft foam with an exact pattern of the high points of the engine, which I then cut out of the foam with a sharp blade. I glued what remained to the fiberboard, which then fit snugly under the removable piece of sole.

The remainder of the floor now had the ¾-inch plywood sole pieces, with 2 inches of foam glued underneath, then a ½-inch air gap, then the ½-inch MDF false floor. It was now certainly a compact floor.

After all this backbreaking work, I was naturally keen to take new readings on the decibel meter. With only the main engine running at the same revolutions per minute as before, my iPhone app meter read 65, a reduction of 20 db! Adding the generator raised this to 70 db, 23 db less than before and now about equivalent to an electric sewing machine. This reduction may not sound like much (forgive the pun), but decibel ratings are logarithmic, so the noise reduction is very noticeable. Now we can comfortably listen to the television or music at anchor, even with the generator running.

In addition to a considerable reduction in noise, there is now no perceptible heat coming through the floorboards, which helps to keep the living area cooler. Heat is carried outside by the engine-room extractor fans, and the noise from them is much reduced too.

Most projects I have undertaken on Britannia resulted in visible improvements, most notably when I renovated the teak-and-holly sole. The noise-and-heat-abatement project, on the other hand, showed no outward improvements, and the cabin looked exactly the same as before I started the job. It was only when the engines were running that the improvement was appreciated.

This method of sound insulation would be very worthwhile for any boat, offering excellent noise reduction for minimal financial outlay. I actually used some spare pieces of MDF to double the wall thickness in the spaces where my two air-conditioning units were installed, and this reduced the noise of the compressor and fan as well.

There are, of course, no labor charges factored into the cost of the job, which took me four days to complete, but messing about on boats is supposed to be fun.

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Marine noise can be extremely annoying and reduce the enjoyment of any voyage. Dynamat marine soundproofing products can efficiently reduce noise at source, typically; boat engine room soundproofing, generators, structural vibration, wave slap noise reduction, thruster noise reduction, noise migration into cabin or deck areas and vibration from the hull and other structures.

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Engine Noise Reduction

• Thread starter Jerry B
• Start date Jun 27, 2003
• Forums for All Owners
• Ask All Sailors

My Universal 10 (in an O'Day 272) seems rather loud while motoring, in comparison to others I've heard in passing. Can anyone recommend a good source of sound insulation that could be used to line the engine box / step area. I've checked auto parts places around my area, but they don't carry it. West Marine has only 10 square feet for $ 70. - yikes!!! There must be a more economical source. Any other suggestions?Thankks,Jerry B.  

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Soundproofing Your Boat

How to install soundproofing for quieter cruising.

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Boat Engine Soundproofing: How to Reduce Noise & Vibrations

In all honesty, I never quite understood the appeal of boats and cruising in them until I was a fair bit into adulthood. It just seemed like a pointless risk to me, the sort of thing you do when you feel like getting the same enjoyment out of lying at the beach is too ordinary for you.

My mind has been changed, though not entirely, by relatively recent events. My family and I were invited to go on a friend’s boat, out into the water to cruise and have fun.

My husband was loving every moment, acting like he was going to buy about 4 different boats as soon as we got back. My kids loved it even more, somehow, taking photos and just having a blast.

Then the noise became noticeable. An ungodly, core-shaking level of loudness that nearly ruined it for me.

I kept thinking about suggesting various solutions and ways to mitigate this to the boat’s owner. Let’s go into them now.

All About Boat Engine Soundproofing

Let’s go over some essentials in regards to the reasons why you should soundproof your engine compartment and the benefits. Next, we’ll explore how to do it in detail and ideally not pay out the nose for it.

Why should you soundproof your boat engine

• The therapeutic and health benefits versus the issues that may arise
• The social benefits versus the social negatives

Let's take a look at both of these. While they may seem obvious, there are a thousand little details that can be forgotten, when discussing this topic.

First of all, let me list some examples of negative consequences to your health if your boat's engine is too loud and vibrates it too much:

• Hearing damage over time. As boats can easily create noise above 110 decibels , this is a very real and very terrifying risk.
• Degradation of your bone and muscle structure. Vibrations , at a high enough intensity, are quite capable of causing these types of physical ailments in some people.
• While not common, they’re still a possible danger and betting that you’ll be one of the lucky ones is never advisable.
• Risk of injury. From miscommunication to slipping up, the ways to injure yourself in these kinds of situations are far too numerous to count.

Now let’s look at the positive aspect. Boating, after all, can be very beneficial to your health.

It reduces stress, anxiety, acts therapeutically towards any mild ailments due to the fresh sea air and even helps keep your wits sharp. After all, remembering all those nautical terms, how to steer a boat and so on do help to keep you on your toes, mentally speaking.

How to soundproof your boat engine

Let’s see how you can reduce the noise of your boat to a level you can cope with, so you can fully enjoy and embrace all the benefits of it.

Be aware that there is no such thing as eliminating the noise fully. Regardless, you can reduce both that and the rumbling to very tolerable levels, making it moot.

There are generally 2 major steps to dealing with the noise:

1. Soundproofing the outboard motors

While most engines have a cover over this type of engine, it usually does very little to mitigate noise. This cover, called the cowling, is largely ineffective unless you supplement it with something far better.

Keep in mind that your cowling is a piece of the engine that you need to tread lightly with. Generally speaking, it’s not that delicate, but some wrong moves can cause issues down the line.

Depending on the material used to make it, it may be more or less prone to malfunctioning, if tampered with, as well as sturdier or more brittle. Make sure to thoroughly consult your manual, first.

Let’s see how you can reduce the noise by installing insulation into the cowling and, optionally, on the insulation as well. While this may seem redundant, with how loud the engine can get, it may not even be enough, despite you potentially soundproofing both.

• Foam can be useful, but it only eliminates the high-frequency sounds. For best results, I recommend getting something like this , since it eliminates both ends of the spectrum, being dense flexible enough to do so.

Make sure to shop around and see what fits your needs best. If you have to, consider bringing in an expert, or at least someone with experience dealing with things like this, to aid you.

• Fit the material, covering as much as you can of the inner cowling. Do not obstruct any air vents or let it touch on moving parts.

Obstructing the air vents can lead to overheating, among other things. At best, this erodes the integrity of the motor and at worst it can be an actual safety hazard, the type that may end up causing an accident.

Furthermore, moving parts can cause friction, if they are obstructed and the possibility for disaster there is endless. If that wasn’t enough, they can even cause total failure of the engine, in some rare cases.

Check if air can still flow regularly. Make sure to not be causing a block anywhere or there might be issues down the line.

• Next, consider the effect you’ve gotten so far. If you think you need more soundproofing, go for a cover on the surface area of the cowling itself.

As a general bit of advice, try not to expect miracles from either the first or second step here. While what you just did will reduce the noisiness by far, it’s still reducing something that’s massive in the first place.

Products like these are generally your best bet. They're custom designed and should be easy to use while being better than any alternatives.

Be wary of slipping these on wrong, however, because the engine might overheat. If something does not look right to you, adjust it.

2. Soundproofing the inboard motors

• These tend to be a lot easier to soundproof, due to being pre-insulated. Get some rubber insulation matting from the choices you can find online or at your nearest store.

Make sure not to buy too much or too little, since that’s a common mistake. Even if it may be tiresome, measuring the surface area you need to cover or using the manual, at least, as a reference, is best.

• Line the insides of the enclosed motor with the matting. I recommend using the self-adhesive ones, for best results and ease of use.

Covering everything you possibly can is best, but be wary of covering too much. The possibility of overheating rears its head here as well if things go poorly.

Generally speaking, you don’t need to pay much attention here, but keep in mind that cracks in the insulation or lopsided application will provide worse results. Go slow and be patient for the best possible outcome.

One thing I recommend is taking your newly insulated motor on a test-run. Carefully maneuvering around the pier itself will give you a good notion of whether it worked or not.

Taking any risks with this is ill-advised and you should always tread with caution. For the best results, checking if everything works methodically will be your best bet.

Not to say you shouldn’t enjoy your newfound quieter cruising, just be understandably slow at first.

Conclusion: On Boat Engine Soundproofing

While it may seem like a big deal, once you first experience it, a noisy boat engine is very much an easy problem to fix. With these steps, you can take measures to both correct the problem and make the most of your boat.

That way, you’ll get all the benefits, without any of the downsides and you’ll only enjoy yourself all the more.

Boat Engine Soundproofing: How to Reduce Noise & Vibrations

Is your boat engine noisy and vibrating hard? In our boat engine soundproofing guide, we talk about why you should soundproof it and how you can do so.

Instructions

• Soundproof The Outboard Motors
• Soundproof The Inboard Motors
• Previous post

How to Soundproof a Boat Engine Compartment: 5 Affordable Tips

Many boat owners are looking for a way to soundproof their boat engine and direct injection diesel engine in particular. They can go way over 100 dB, depending on the size and type. And that “knock” that older diesel engines make is really what ticks many people off.

But regardless of how loud the engine is, it’s the material surrounding it that determines how much of that noise escapes from the engine compartment. So that’s where the focus of this article will be. These are the best marine soundproofing tips that you can implement by yourself and for an affordable price.

1. Insulate the inboard engine compartment

This is something you must get right, otherwise you could spend a lot of money without reducing the noise. To insulate a boat engine properly. the material that you use must be able to block low frequency sounds. Because that’s really what any engine does. It produces vibrations and these vibrations resonate on the surrounding material.

You know those acoustic foam panels  with those eggshell crater design? Yeah.. that’s not going to do much for you. Those foam panels can only reduce the echo , but they can’t really block the noise to any great degree, especially low frequencies.

Instead, you should get a sound deadening material that is typically used for car engines. These materials are dense and strong enough to block impact noise. They are also heat and liquid resistant.

The one that I personally recommend for projects like this one is FatMat  because I’ve seen it in action and it makes a big difference. My friend used it to soundproof his pickup truck. The engine and the cabin and it made a huge difference for traffic noise and engine noise. So I’m confident that it would work well for a boat engine as well. Plus the product information states that it can be used for marine soundproofing.

There are other similar items such as Dynamat and Noico, and there’s also standard Mass Loaded Vinyl. All of these materials are similar and would probably work well.

I’ve used Mass Loaded Vinyl for other projects and it works well. The only downside is that it’s not self-adhesive so you need to use a spray adhesive for it. Still, not a big deal by any means.

But for this project I would stick with FatMat because I’ve seen it work and it’s more affordable. It’s self-adhesive and all you need to do is stick it on the engine compartment.

Make sure that the compartment is properly covered once you’re done. If there’s still noise bothering you after you’ve done this, you can always add more layers to improve the thickness and insulation.

2. Insulate the outboard engine

Insulating the outboard motor is technically easier but the effects will not be as dramatic. Simply because it’s on the surface and therefore the noise is closer to your ears.

The outboard engine is covered with cowling, usually made of fiberglass. This is a thin cover that does block some impact noise. But if you can make it thicker by using dense material it will be even better.

Again I recommend using FatMat for this project because it’s efficient against low frequency vibration noise, it’s affordable and easy to cut to size. You can cover either the inside or the outside of the cowling.

Covering the inside would be better because the engine noise would then hit this softer material first. But this would require removing the cowling with most engines and then placing the material and returning it back on. An easier way to do this is to simply install the FatMat on the outside.

The downside of this method is somewhat reduced effectiveness and most of all it would look pretty ugly. So overall you’ll probably need to get your hands dirty to get the optimum result in this case.

But if you’re only worried about the “flashiness” of the FatMat looking ugly on your motor, you can get a darker insulation material that is not as obvious until you get pretty close to it. One that is similar to FatMat but also looks better is the black Noico sound deadener . It’s self adhesive and the installation process is the same with both. Simply stick it to any surface that you want to insulate and you’re done.

Speaking of which, you’ll want to cover as much of the area as possible. Make sure to leave the air vents and any other necessary openings intact, but cover the rest of the area completely.

3. Cover any gaps and cracks you find

Any gaps between sheets of insulating material should be covered with aluminium foil tape . This tape can also be used to cover any small gaps or cracks in the cowling and the engine compartment.

You don’t want to leave any unnecessary exit areas for sound and that’s really the whole logic behind doing this. I also advise using a few layers on each gap for better insulation.

4. Examine the cowling for large cracks and loose parts

Examine the cowling on the outboard motor. There can be some loose or broken parts. If any are present, they might amplify the vibration noise when the engine is working.

In that case either tighten the loose parts or use the aluminium foil tape to make them immovable. If the cowling is severely cracked and some parts have taken a life of their own, you may have to replace it entirely.

5. Add thickness to the floor

This is not a solution for every boat. It depends on the design. But for example if the boat cabin or starboard is directly above the inboard motor, it would make sense to cover the floor with a sound deadening mat.

It should be at least 1/2 inch thick, waterproof and non-slip. I would personally go with  3/4 inch thick rubber mat . If placed in a fancy cabin it wouldn’t look very nice, but you can always cover it with something nicer like a rug or some type of cover.

This will obviously not block the noise entirely because it can travel through air as well. But it will definitely muffle the noise coming through the floor and that is a noticeable portion of the problem.

To conclude

Marine soundproofing is an area that most soundproof experts avoid. Why? Because it’s impossible to get the noise completely under control. We are perfectionists by nature and want to BLOCK the noise. It’s a professional illness of sorts.

But with engines that’s almost never possible. Engines need to breathe, or they’ll overheat, or they need a lot of space for the working parts. You can’t soundproof anything as long as air can pass through. But sometimes we have to make compromises and focus on things that we can change.

Speaking of which, any structure that is made thicker and denser will by nature be more soundproof. This is common science. So if you can create a thicker and denser barrier between the source of the noise (in this case the engine) and the surrounding environment it WILL make a difference.

So you can focus on surrounding the engine with additional soundproofing material. Or you can try to insulate the floor or the entire boat cabin. Or in an ideal situation you would do boat. Uh. I mean both. Having said that, from a noise reduction perspective it’s always better to tackle the source of the noise as close as possible.

Hopefully this helps! If you have some personal experience with marine soundproofing, feel free to share it in the comment section below.

Soundproof expert and a staunch opponent of noise. This website is a free source of information on how to 'keep it down a notch'. I update the content regularly to keep up with advancements in the soundproofing industry.

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Handy Tips on How To Quiet Your Boat

A constantly vibrating boat can lead to loose bolts and introduce minor damages to various parts of the boat. As a result, it becomes crucial to resolving the vibrating boat issue. But how do you do it?

The quickest methods for making a boat quiet include installing soundproofing and or sound dampening materials into the boat’s cowling. Materials including rubber (self-adhesive or non-adhesive) and anti-vibration membrane in addition to aluminum layer are highly advisable.

This article covers essential yet practical tips to quiet your boat, along with some FAQs related to the topic. Please follow the article until the end.

How Do You Reduce Outboard and Inboard Noise?

As an affiliate, I may collect a share of sales or other compensation from the links on this page.

Any loose bolts, nuts, and or rivets are the significant reasons behind a noisy boat. Parts can become loose with time, so check for any such loose bolts, nuts, or screws and tighten them.

Excessive friction increases the motor’s noise by extreme levels. Consider lubricating the engine for smooth and much quieter operation. There exist a marine engine lubrication system that aims to reduce friction in marine engines.

If the noise still exists, it probably requires another fix discussed below.

Noise Reduction on Outboard Motor To Quiet Your Boat

• The cowling is the outboard engine’s cover shipped with the engine that barely aids noise reduction. Therefore, it’s advisable to install another layer of heatproof and waterproof cowling over the current cover. Avoid removing the original cowling since the removal process can leave damage to the engine.
• A DIY muffler made of PVC acts as a silencer for an outboard motor.

Noise Reduction on Inboard Motor

• Installation of rubber mats within the motor area acting as insulation is the best way to reduce noise on an inboard motorboat. Ensure not to block air vents causing an overheated boat.
• Use noise control barrier material that can absorb the vibrations leading to a quieter boat. A barrier of 32″x54′ with a 1″ thickness will cost AU$155+. These barriers are self-adhesive, so peel and stick to the surface.

How Effective Is Soundproofing On A Boat?

It’s impossible to deflect all the noise generated in a boat. Still, many people get curious about how effective it will be to install some soundproofing on their ship. Here’s the answer.

A boater can expect to eliminate up to 60%-70% of sound generated in the boat; if you quiet your boat properly. Soundproofing panels cannot block the noise entirely but can dampen the low-frequency sound waves with long wavelengths.

Installing multiple soundproofing panels will be effective, but it’s useless to install several layers on a given surface. Moreover, the quality of panels governs the amount of noise blocked.

Using thick and high-density foam sheets will deflect most of the noise, whereas soft and low-density pads will allow most noise to pass through them.

How to Make an Aluminum Boat Quieter

Please follow this guide to make your aluminum boat quitter step-by-step.

Required Items

• Non-expandable foam filling
• Ensure tightening of any loose bolts, nuts, screws, and rivets. Fix the leaks in the boat (if any). Finally, make sure that the structure of the boat has no damages before proceeding.
• Fill the gaps in between the hull and floor braces with the non-expanding foam. Please note that the use of expanding foam in an aluminum Jon boat will rip off the rivets.
• Take the measurements of your boat’s floor’s structure and cut the Styrofoam accordingly. Tack the sheet to the floor with caulk. Remember to leave some space for the drainage plug.
• Please note that most people skip this step, assuming it not so important, which is false.
• Just like you installed the Styrofoam, install the carpet above the Styrofoam sheet. Cut the carpet slightly longer (1-3 inches) so that the ends can extend up the wall.
• There are some outdoor carpets washable with a water hose. Try using them for the best results (since they’re water-friendly).
• Better the Styrofoam, carpet, and foam sticks to the floor, better the results. 
• Use self-adhesive sheets (if possible) as they’ll stick perfectly. 
• Avoid using nails or sharp objects to tack the sheets.
• If you’re looking to painting your boat, do so after installing the soundproofing sheets.

Why Do You need To Quiet Your Boat?

Even if you’re fine with the annoying noise produced by your boat, here are a few reasons to quiet it:

• For the sake of compliant sailing, you’re required to limit your boat’s noise. In Alabama, noise shouldn’t exceed 86dB when measured 50 feet away from the ship. In New Mexico, you’ll have to ensure not to let others generate a complaint due to your noisy boat.
• Soundproofing helps keep the engines cooler during high temperatures.
• A fishing boat must be soundproofed, or else the fish would swim away to another end of the water body.

Tips For Effective Soundproofing

• Create proper templates before cutting the soundproofing sheets. Take appropriate measurements from every possible side and draw a rough design on paper for better understanding.
• Always leave enough space for ventilation.
• Do not use soundproofing materials that aren’t waterproof, or else you won’t get enough soundproofing.
• Ensure a gap of six inches between the soundproofing sheet(s) and exhaust manifolds.
• Cut the sheets with sharp tools for precise and accurate cutting. It also ensures the edges don’t get torn or damaged.
• Use high-quality adhesive tape for sealing the edges.
• There should be no gap or cavity between the soundproofing sheets.

Effective Sound-blocking Barriers For Boats

Please note that the boat market is filled with thousands of varieties of soundproofing sheets. Below are a few of them:

Fiberglass Composite : They’re highly flexible barriers ideal for cabin’s ceiling and walls. Use them on noisy pipes for insulation.

Mass load Vinyl : These rigid barriers are made of sand, silt, and fine metal particles that all together absorb the noise and vibration. Install them on your ceiling and or walls for effective noise cancellation. 

Temporary Vinyl Barriers : These barriers fit perfectly on the floor, line hulls, line engine compartments, or cover hatches that offer a peaceful sleep on the boat. As the name suggests, they’re not suited in the long run.

Soundproofing Coating : You can apply a coating of soundproofing liquid that’s capable of absorbing sound and converting it into low-grade heat. These coatings are non-toxic, water-based, resistant to corrosion, and applied to hulls, hatch covers, and engine compartments.

Vibra Block : This sound dampening sheet is industrial-grade that says a lot about its quality. Their primary use revolves around steel hatch covers, compartments, and pump closure.

It’s a lightweight product that doesn’t ruin your boat’s appearance.

Acoustic Foam Panels : Such panels can absorb and deflect sound vibrations. These panels are resistant to moisture and hence can be washed several times. Installation areas include walls, ceilings, and floors.

Echo Absorber Acoustic Panels : Echo absorber panels are majorly made of recycled cotton and are quite popular due to their low cost. Unfortunately, these panels are mountable only on flat surfaces. 

Frequently Asked Questions (FAQs)

Is a 2-stroke outboard motor quieter than a 4-stroke outboard motor.

Most 4-stoke outboard engines are much quieter than any 2-stroke outboard motor, whether idle or running. The noise levels of different 4-stroke outboard engines do differ based on the manufacturer.

Why are 2-stroke engines so loud?

Any 2-stroke engine would fire two times more than a 4-stroke engine. Additionally, 2-stroke engines lack valves to intake and exhaust, leading to increased noise.

What Areas Can Be Soundproofed?

Not only floor, but you can also install overhead barriers and install soundproofing sheets on the walls in a cabin.

Manual installation of soundproofing materials on a boat can be tiresome, but that’s the only way to achieve the goal.

Avoid blocking air vents and make sure the material doesn’t touch any moving parts.

Also, try your best to keep the soundproofing materials out of direct contact with the extremely hot boat parts, as that can start a fire.

• https://www.youtube.com/watch?v=jpvsHWFFoWY
• https://forums.ybw.com/index.php?threads/reducing-outboard-engine-noise.373953/
• https://www.westmarine.com/engine-sound-insulation
• https://goneoutdoors.com/make-aluminum-fishing-boats-quiet-5293666.html
• https://www.marineinsight.com/tech/ships-main-engine-lubrication-system-explained/
• https://www.soundproofcow.com/soundproof-a-space-restaurant-office/soundproof-a-car-compressor-boat-pump-or-other-equipment/boat-soundproofing-2/#boat-parts-need-soundproofing

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