10 Best Sealant for Boat Windows [2022 Buying Guide]

There are several intricate things in your boat that are susceptible to damage, and one of them is leaky windows. Since boats endure a wide variety of conditions, keeping the water out from the vessel is essential.

Best Sealant for Boat Windows

Picking up the wrong marine sealant can create a lot of problems. When the seals in the boat windows become damaged or break, they erode. Plus, the situation can turn from bad to worse pretty quickly.

Not to mention, you will be fixing leaky windows again next year with other problems. You do not want to pile up problems.

So, what is the silver lining here?

You want the best sealant for boat windows. And you want to ensure that all the leaks in the windows are correctly sealed to not only keep your vessel above water but to keep everyone and everything in the boat safe and protected.

However, there are several manufacturers out there that do not make the shopping process easier. Figuring out which marine sealant to buy can be quite challenging.

Therefore, we have come to your rescue to reduce some of your stress. Check out the best sealants below:

Comparing 10 Best Sealant for Boat Windows

3M Marine Adhesive Sealant 4200Polyurethane Check Price
Star Brite Marine Silicone SealantSilicone Check Price
Boat Life SealantPolyurethane and Silicone Check Price
Loctite Marine SealantSilicone Check Price
Sikaflex-291 Adhesive and SealantPolyurethane Check Price
3M Marine Adhesive/SealantPolyurethane Check Price
Dap 00694 Auto/Marine SealantRTV Silicone Check Price
Permatex 80050 Adhesive SealantRTV Silicone Check Price
Seal Bond Marine Adhesive SealantPolyether Check Price
3M Marine Adhesive Sealant 5200Polyurethane Check Price

1. 3M Marine Adhesive Sealant 4200

3M Marine Adhesive Sealant 4200

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  • A sticky and thick polyurethane sealant
  • Cures in about a day
  • Medium strength formula
  • Ideal for stern joints, rub-rails, access plates, and other sun shielded area

Are you in search of an excellent waterproof sealant?

This thick polyurethane sealant will bond just about anything. Plus, it has extreme adhesion. It will save you from frustration as this adhesive requires minimal effort.

What’s more!

You do not have to mix this one-part adhesive sealant. It cures fast, almost within twenty-four hours. Thus, you can take your boat into the water quicker and enjoy all the water activities.

Do you know what makes this sealant the best option?

This marine adhesive sealant is highly praised because it is capable of lasting long. This formula is composed of a potent polyurethane polymer that defies saltwater and weathering.

Moreover, this medium-strength formula keeps the bonds strong yet flexible. These bonds remain rigid and flexible even during shock, structural, movement, or vibration.

What else?

This semi-permanent adhesive allows individuals to disassemble the bonded parts without any damage. Furthermore, you can use a 3m marine sealant below the waterline. Plus, it is also perfect for sealing above the waterline.

Not to mention!

This formula is ideal for sealing areas that are protected from the sun, access plates, rub-rails, and joints.

Oddly enough, there are a few downsides. The plastic nozzle included might not safely dispense the formula and can create a huge mess. Plus, it might be hard to clean because it is sticky and thick.

  • Cures instantly
  • Long-lasting
  • Semi-permanent 
  • Flexible and potent bond
  • Superbly seal above and below the waterline
  • Economical
  • Problematic plastic nozzle
  • Difficult to clean

No products found.

2. Star Brite Marine Silicone Sealant – Delivers Pleasing Results

Star Brite Marine Silicone Sealant

No products found.

  • Seals well on flexible areas
  • Cures completely in twenty-four hours
  • Ideal for below and above the waterline and for other materials
  • A potent silicone formula

Are you looking for a long-lasting sealant that seals well on flexible areas?

This product will not let you down because it is good enough to solve any leak issues. This formula applies nicely, and it dries clear.

What’s more!

This silicone sealant is not manufactured for marine purposes only. You can use it anywhere.

Moreover, this formula is designed to bond some plastics, metal, glass, wood, and fiberglass.

Plus, you can use it below and above the waterline.

Do you prefer a water-resistant and airtight bond?

This product will not dishearten you. It provides an airtight and waterproof bond. However, you can easily remove it.

Furthermore, this heavy-duty and multipurpose sealant is ideal for cracks, joints, deck hardware, hull fittings, portholes, windshields, etc. 

What else?

The sealant cures in about twenty-four hours. Moreover, this sealant is potent enough to combat solvents, chemicals, weathering, and sunlight.

Surprisingly enough, this great sealant is slightly pricey as compared to other marine adhesives available. Plus, you have to handle the tube with extra care because it breaks easily, and it can result in a lot of mess.

  • Multipurpose 
  • Dries fast
  • Long-lasting 
  • Dries clear
  • Delivers water-resistant and airtight bond
  • A bit pricey
  • Cheaply made tube

No products found.

3. Boat Life Sealant – Seals for Life

Boat Life Sealant

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  • You can use the same bottle later by capping it
  • Attaches to several materials and most plastics
  • Multipurpose, non-corrosive sealant 
  • Stops mildew growth
  • No discoloration after application

Are you in need of a quick-fix because you do not have time to research which adhesive should be used for which material?

This ultimate boat sealant is the perfect one-size-fits-all. It is best for non-professional boat owners who like to fix things quickly with minimal effort.

What’s more!

Several boat owners prefer this sealant because it is easy to use, seals everything perfectly, and does not fade away like the other adhesives.

Moreover, the process of application is relatively easy. You can use your fingers or different tools to make a well-protected and smooth seal. However, the procedure can be a bit messy, so make sure you have enough paper towels to clean up the mess.

What else?

You can use this sealant for windshields, below and above the waterline, cracks, vinyl ports, hull fittings, etc.

Furthermore, it provides durable, watertight, flexible, and permanent seals for joints. Plus, this formula can be used as a caulk, and it usually cures within twenty-four hours.

Not to mention!

It is fast-curing, non-sagging, low odor, acid-free, non-corrosive, non-yellowing, and mildew resistant. Besides being a great sealant, many reviewers said that setting up to use this sealant might take a while.

  • Long-lasting 
  • Very flexible 
  • Used as a caulk
  • Straightforward cleaning
  • Easy-to-use
  • Cures in 24 hours
  • Not the most potent adhesive
  • Setup takes time
  • An application can be a bit messy

No products found.

4. Loctite Plumber and Marine Clear Adhesive

Loctite Plumber and Marine Clear Adhesive

No products found.

  • Ideal for wet and irregular surfaces
  • Available in a pack of six
  • A thick formula
  • Clear adhesive
  • All-purpose formula

Do you know why this sealant is a perfect pick? 

Loctite is an excellent adhesive that works well on irregular and wet surfaces. It perfectly works as a bandaid to prevent all kinds of leakage.

Moreover, it superbly patches up all the small holes and leaks, whether in an aluminum vessel or plastic, metal, fiberglass, vinyl, and rubber.

What else?

This marine silicone sealant is waterproof, and it creates a watertight seal. Thus, it makes this formula ideal for any outdoor waterproof repairs and projects and high-moisture plumbing repairs.

Moreover, the formula has a no-drip, thick consistency, and it dries transparently. However, you have to use this adhesive in a well-ventilated area, and this sealant might take more than twenty-four hours to cure.

What’s more!

This product is relatively easy to use, but it can be a bit messy. Plus, the formula is not too runny, and the bonds remain completely solid.

Not to mention!

This product comes in a pack of six, and it works like a charm. It looks terrible at first, but once the formula dries, it gives the material a tough and rubbery feel.

  • Waterproof
  • Long-lasting
  • Straightforward to use
  • Seals perfectly
  • Dries transparent
  • Can be a bit messy
  • Cures in more than 24 hours

No products found.

5. Sikaflex-291 Adhesive and Sealant – A Durable Product

Sikaflex-291 Adhesive and Sealant

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  • Black sealant
  • Resistance against saltwater
  • Strong adhesive
  • Paintable and sandable

Are you craving for the nastiest adhesive that is stronger and is mechanically separated?

You might want to check out Sikaflex-291. It is a marine-grade polyurethane sealant and adhesive. Moreover, this formula is all-purpose that several boat builders use.

What’s more!

It marvelously cures metal, wood, gel-coat, fiberglass. Plus, you also use it for light-duty bonding. Furthermore, this durable formula is relatively easy to work with.

Do you know what makes this sealant more impressive?

This polyurethane sealant is waterproof, provides excellent bond, is sandable and paintable, can stellarly combat against saltwater, and you can use it below or above the waterline.

Plus, this black sealant cures instantly; thus, it speeds up the work where time is the issue.

Moreover, this formula is ideal for bonding bed boat components, fixture sealing, deck fitting, shower, and sink sealing, interior sealing, vent sealing, and windows.

Besides being a great product, several users found some downsides. The application of this formula can create a mess, and after opening, this product does not store well.

  • Waterproof 
  • Cures instantly
  • Multipurpose 
  • Potent 
  • Durable
  • Straightforward to use
  • Storage is a hassle
  • Messy while handling

No products found.

6. 3M Marine Adhesive/Sealant – Perfect for Marine Purposes

3M Marine Adhesive Sealant

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  • Ideal for the marine environment
  • Combats various situations, saltwater, and weathering
  • Creates tough bonds
  • Tack-free time is 12 hours
  • Cures in 48 hours

3M marine adhesive sealant is manufactured to meet the demands of the marine environment. Thus, it makes this product perfect to create tough bonds below and above the waterline.

What’s more!

It is a powerful formula that can combat shock, shrinking, swelling, and vibrations. Moreover, it is a reliable and durable solution that provides fast cures.

Plus, it offers watertight seals. The tack-free time is typically twelve hours, and it cures within forty-eight hours.

What else?

This marine adhesive sealant provides permanent adhesion to fiberglass, Gelcoat, and wood. Furthermore, this formula is flexible and enables structural movement.

That’s not all!

It can marvelously resist saltwater and weathering. Plus, it does its job perfectly by bonding wood to fiberglass, fiberglass hull to fiberglass deck, under moldings, portholes, and deck fittings, etc.

What’s stellar about this sealant is that it makes the bonding quite tough, and they are long-lasting. Plus, this pasty adhesive stunningly repairs any leaks. However, the drying process may take a lot of time, but the whole process is worth waiting for.

Not to mention, keep a very low pressure on the tube when applying this sealant because the tube tends to explode the formula. Once you open the formula, you might find it challenging to keep it airtight.

Since the product provides permanent adhesion, it is quite challenging to remove. Therefore, it is better that you wear gloves.

Moreover, this formula is a little messy to work with, and cleaning can become a hassle, especially if the formula comes in contact with your skin.

  • Potent formula
  • Durable and reliable 
  • Permanent and flexible adhesion
  • Cures fastly
  • Water-resistant 
  • Long-lasting
  • Quite messy
  • Require hand gloves 
  • Keeping the product airtight is a hassle

No products found.

7. Dap 00694 Auto/Marine Sealant – Heavy-duty Silicone Adhesive

Dap 00694 Auto Marine Sealant

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  • Clear sealant
  • A 100% RTV silicone sealant
  • Cures in a day at room temperature
  • Ideal for automotive and marine repairs

Are you looking for a water-resistant, super adhering formula that can cure at room temperature?

Dap might be the product you need. It is 100% RTV silicone, which means that it can cure at room temperature.

Moreover, this silicone rubber type is relatively durable and easy to use.

Several users mentioned that the application of this product is extremely straightforward. Also, the cleaning afterward will not take much of your time.

How is the process easy?

You do not need any protective gloves before applying this adhesive. All you have to do is that you have to tidy the surfaces that you want to bond and apply the formula. Use your finger to spread it evenly.

Then, to clean it up, you need soap and warm water. Allow the surface to dry for an entire day. That’s it.

What’s more!

This clear sealant is waterproof and has greater longevity. Plus, it is strong enough to resist contraction, expansion, and vibration. The adhesive remains flexible and does not shrink or crack.

Furthermore, this bond is ideal for the marine and automotive repair and maintenance.

Oddly enough, users found some negative aspects about it too.

This economical product comes in cheaply manufactured packaging and screw-cap. Thus, it sometimes makes the application a hassle.

Moreover, the tube might split open sometimes while using, and the glue can dry and harden up inside the tube.

  • Flexible 
  • Potent 
  • Long-lasting 
  • Easy-to-use
  • Durable
  • Water-resistant
  • Economical
  • Cumbersome application
  • Cheaply-made screw-cap and packaging

No products found.

8. Permatex 80050 Adhesive Sealant – A Toolbox Must-have

Permatex 80050 Adhesive Sealant

No products found.

  • An RTV silicone
  • Cures at -59 to 204 degrees celsius
  • Multipurpose 
  • Can combat against vibration and weather

This is another excellent RTV silicone adhesive that does the job, and it is not too pricey. You will be pleased with its results.

Permatex always delivers the best products that help people in tackling their problems. This sealant by Permatex is all-purpose, and it does a wonderful job in bonding, repairing, sealing, or securing vinyl, fabric, plastic, glass, or metal.

What else?

Since it is an RTV silicone sealant, it cures at a temperature of 59 to 204 degrees celsius. It stellarly bonds door frames, windows, seams and roofs, and vinyl tops.

Not to mention!

This adhesive sealant is transparent, flexible, durable, waterproof, and can combat vibration and weather. Moreover, it does not act as a dust magnet, and this formula is relatively easy to clean from hands.

Besides delivering excellent results, many users mentioned that its packaging and cap are of low quality.

  • Cures quickly
  • Flexible
  • Budget-friendly
  • Durable 
  • Waterproof
  • Not a dust magnet
  • Easy-to-use and clean
  • Poor cap quality
  • Cheap packaging

No products found.

9. Seal Bond Marine/Industrial Adhesive Sealant

Seal Bond Marine Industrial Adhesive Sealant

No products found.

  • Creates tough bonds
  • A polyether sealant
  • Works above the waterline only
  • UV resistant and non-flammable
  • Solvent-free and flexible

This stellar sealer has high adhesive strength, and it is the perfect product for marine purposes. It has excellent packaging, and the formula discharges from the tube pretty well.

What’s more!

The sealant bonds thoroughly and quickly. Plus, it forms a rigid bond, and it is relatively easy to work with. It is a budget-friendly high-performance adhesive sealant that is only suitable above the waterline.

What makes this sealant more impressive?

It works wonders in various temperature ranges, is non-flammable, UV resistant, and free from all the isocyanate and solvents.

Moreover, this formula is 100% solid, adheres well, and is weather resistant. Thus, it does not shrink and remain flexible once cured.

However, you have to be careful while using this formula because of its potent strength and holding power. It is better to wear gloves before using them because it does not come off easy if it comes in contact with the skin.

Since it is so strong, cleaning up becomes much more difficult without using harsh solvents.

  • Weather-resistant 
  • Flexible 
  • Superior adhesion
  • Solvent-free
  • Economical
  • Cleaning is a hassle
  • The formula does not come off easy

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10. 3M Marine Adhesive Sealant 5200 – A Seaworthy Sealant

3M Marine Adhesive Sealant 5200

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  • Offers permanent bonding
  • Ideal for small projects
  • Cures in five to seven days
  • The formula can withstand several conditions
  • Requires no mixing

Are you looking for a Universal Adhesive? This sealant is close to being universal. It is a little bit pricey, but it does the job.

What kind of job?

Almost everything. It provides permanent bonding, and it seals, bonds, and attaches the interiors of boats, RVs on the exterior, and below and above the waterline.

Moreover, it is a long-lasting polyurethane polymer formula that can resist saltwater and weathering. The formula does not even peel or crack. It stays flexible and retains potent bonds during shock, structural movement, and vibration.

What’s more!

It is high-strength, moisture-curing, and creates flexible and tough bonds. This adhesive sealant needs no mixing, and it cures entirely in five to seven days.

Without any doubt, it is an outstanding adhesive that takes a while to cure, but the cleaning is not cumbersome. With acetone’s help, you can easily clean up the excess and tidy it up with a razor knife.

Furthermore, it helps in sealing under moldings, leaky nuts, bolts, screws, and windows on boats, portholes, deck housing, etc. By using the formula carefully, you can prevent mess. Plus, it seals up tightly and nicely after using it.

Surprisingly enough, this marine sealant is the best choice for individuals who want to cure massive projects. Plus, it is tough to lift off the residue.

  • Long-lasting
  • High-strength
  • Seals tightly after usage
  • Flexible
  • Moisture-curing
  • Not suitable for massive projects
  • Lifting off residue is tough

No products found.

Sealant for Boat Windows Buyer's Guide:

Sealant for Boat Windows Buying Guide

Before you begin your journey of picking the right sealant, it is essential to know which type of adhesive you need and for which purpose.

Moreover, you must explore your options and understand all the features before selecting one. You should have all the critical information, and we are here to help you out in this regard.

What's more!

To make your sealant for boat window shopping stress-free and make the decision-making process easy for you, we have compiled a detailed buying guide. Thus, it will help you make the most of it.

These are the questions you have to ask yourself before buying a sealant:

  • Is the adhesive sealant costly or inexpensive? It is essential to check for the quoted price. Plus, you have to make sure that the price does not compromise the quality.
  • Is it waterproof? Will it be able to sustain the flexibility and not fade?
  • Will the application be easy? Or the tube will explode the content?
  • Does this product ensure that it will last long?
  • Is it mildew, mold, or a dirt magnet?
  • Does it repel UV, solvents, and chemicals?
  • Which kind of marine sealant will you opt for? There are different kinds of marine sealants available, and each adhesive is suitable for various materials.

You might be thinking about the different types of sealants.

Don't worry! We have mentioned all the kinds of adhesives that you should know.

Before jumping towards the various kinds of sealants, we will first discuss the difference between the adhesive sealant and the non-adhesive sealant.

Adhesive Sealant:

Adhesive sealants, as the name suggests, possess adhesive properties. Thus, it can seal fittings and can bond mechanically to different materials. However, it takes about 24 hours to cure completely, which is quite long.

Non-adhesive Sealant:

This kind of sealant usually relies on a bolt, screw, or fitting to build a water-resistant seal. It is a regular sealant, and you cannot rely on this formula to hold any material in place.

Let's move on to types of sealants.

Types of Sealants:


These sealants create the strongest and tough mechanical bonds when they are applied on the correct surface.

What's impressive about these sealants is that they are UV resistant. Plus, you can use them below and above the waterline.

Moreover, these sealants provide permanent adhesion, and they should only be used when you do not want any surface to be separated or removed.


Silicone generally is the static synthetic polymer compound, and it belongs to the rubber family.

Do you know what boat users love about this sealant?

It is an excellent insulator, heat resistant, and UV resistant. However, the only downside is that it is not a potent adhesive as compared to polyurethane. Plus, it might become impractical to use it below the waterline.


These sealants are synthetic rubber formula that creates a powerful mechanical bond. These formulas stellarly resist oil, fuel, and UV. Plus, it prevents the surface from corrosion.

Not to mention, these sealants are excellent electrical insulators, and they resist all kinds of thermal changes, impact, shock, and vibration. Moreover, you can easily paint on it as well.

Benefits of Using Marine Sealant Around the Boat Windows:

Marine sealants are valuable investments, especially for boat owners. They provide a watertight and airtight seal between the surfaces on the vessel.

What's more!

Many times, the water does not come through the hull's gaping hole but gaps in the boat windows. Boat windows can damage away quickly; therefore, it is essential to seal them properly.

So why is it crucial to maintain an adhesive sealant around the boat windows? The reasons are as follows: 

Protect Boat's Interior:

Wherever your window leak maybe, it can result in a lot of water or less. This leakage can damage your boat's interior over time. Plus, the repair might become expensive, or you might have to replace the entire interior.

Moreover, water damage causes the timber to become warped, you have to replace the fabrics, and electronics become damaged. Instead of revamping the entire boat interior, it is better to apply the adhesive sealant around the boat windows every year.

Increase Longevity of Boat Windows:

Sealant around the windows deteriorates over time, and you have to replace it; otherwise, it can erode entirely. The damaged seals allow the water to seep in, and it comes in contact with the windows' laminated glass.

Once the contact occurs, deterioration begins. It damages the inner layer and the appearance changes; thus, you have to replace the boat windows.

Furthermore, maintaining the sealant prevents all these situations in the long run and helps you save money.

Offers Extra Features:

The sealants not only make the vessel sturdy, increase the lifespan, or prevent leaks, but they also provide several other features.

Several sealants are UV resistant, blocks noise, and prevent shock, vibration, swelling, and shrinking.

Resale Value Upticks:

Selling your boat becomes problematic when it is leaking because it decreases its value. The seeping of unwanted water inside the vessel becomes a red flag for potential buyers.

If you notice any leaks from the window, seal them up quickly before the situation gets out of hand. Plus, if you want to sell the boat in the future, you know that your boat is waterproof.

Frequently Asked Questions

What is a marine sealant?

A marine sealant is waterproof, and it repels the growth of mildew and mold. Moreover, these seals do not become yellow when they are applied above the waterline.

They are adhesive, and they can bond bare or painted non-oily woods, abraded rubber, fiberglass, glass, metal, and plastic.

Furthermore, they can quickly solve leaking issues, cracks, and dents in boats and other materials.

How does the adhesive sealant work?

The adhesive sealant is a mechanical seal that penetrates through openings or joints in materials. This product is very much similar to caulking, and it can resist heat, dust, and noise.

Therefore, if you want to seal the leaks, dents, and cracks, you can count on this product. Plus, it prevents expensive maintenance costs.

What makes adhesive sealants beneficial?

• They are an excellent solution to deal with any boat issues like leaks, cracks, and dents.

• They prevent expensive maintenance costs. Plus, they avert leaky problems from becoming worse.

• These formulas increase the vessel’s lifespan, make them durable, and improve the look.

• It is the best protective option for your boat’s issues.

Do adhesive sealants have warranties?

All these adhesive sealants reviewed in our post possess different warranties. Several manufacturers do not mention warranties on the product’s label or its description.

But, you can contact the specific adhesive sealant manufacturer’s customer service to learn more about the product’s warranty.

Moreover, it is a crucial factor to consider before purchasing an adhesive sealant because it will ensure that you will get the right service and product that you truly deserve. Therefore, warranties are essential.

How will you maintain or take care of your boat through an adhesive sealant?

Boat owners are aware that upkeeping the boat is demanding and is undoubtedly a costly investment. It needs proper care, and once you ignore these small issues, you have to pay more due to expensive repairs.

Therefore, the right marine sealant can extend the boat’s lifespan and provide maximum protection and best care. It makes the whole process less exhausting.

You have to ensure that you should use the adhesive sealant properly. Apply the sealant in the right amounts wherever you want. Plus, re-apply it in seasons as mentioned in the product’s label.


Prevention is always better than cure. Therefore, when it comes to upkeeping the boat windows, it is better to prevent the situation. It is better to keep an eye on the amount of water seeping in to take immediate action.

Moreover, boat window leakages can worsen the situation, but you can protect your boat with the right product.

What's more!

We have compiled this informative post to help you make an informed decision. Now you may have learned that what is the best sealant for boat windows. 

You need a high-quality adhesive sealant if you want to fix the leaky windows entirely. We have reviewed all the suitable sealants. You can narrow your choices down and select the best one.

So which adhesive sealant will you go for your boat windows?

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