The Best Marine Sealants in 2024

There is no denying that the hull of your boat needs to be hole-free, especially if you take it fishing out in the open seas. However, your boat will not remain pristine and perfect forever and holes will start appearing in the hull eventually. It is the reason why you will need a tube of the best marine sealant always close at hand.

A marine sealant is different from other regular sealants in the sense that it can withstand the harsh conditions brought about by the saltwater environment. Saltwater is highly corrosive, which makes normal sealants break down, thereby causing leaks and more severe damage.

However, keep in mind that not just because the label in a product indicated that it is a marine sealant, it does not necessarily mean that it will protect your boat well. You still need to find a suitable marine sealant that you can afford, or else you risk losing your boat. Here are short reviews of some of the best sealants that you can buy right now.

Best Marine Sealant Reviews

1. Gorilla Clear 100 Percent Silicone Sealant

Gorilla Glue is one of the most popular adhesive brands right now. This company also produces quality sealants – one of which is the Gorilla Clear considered a great marine silicone sealant option. What I liked about it is that it is versatile. You can use it for home repairs while also being rugged enough to use on your fishing boat even on saltwater.

This sealant is completely made of silicone, so you can be sure that it is completely waterproof. As mentioned earlier, it can also withstand the damaging effects of saltwater. You can be sure that any repairs where you used this sealant will hold for years regardless of where you use it.

Aside from rain and saltwater, this waterproof sealant for boats is also excellent when it comes to resisting the UV rays of the sun. Unlike other sealants, it will not turn a sickly yellow color over time. It will not also dry up and become brittle. It means that you will not be stripping and reapplying the sealant every couple of months or so.

This product is also rather easy to apply. You can get it in tubes and use a caulking gun for application, or you can buy the small pouches for small emergency repairs. This product levels easily, thereby promoting ease in applying evenly and cleanly. It is good news if you will be painting over the sealant because you will only need to sand it a bit to even out the surface.

I do have a problem with this marine caulking sealant, though, and that is it does not have the same durability as actual marine sealants. It is an all-purpose sealant, so it requires you to remove the old sealant and reapply it every couple of months.

2. 3M 5200 Marine Adhesive Sealant

3M is famous for making some of the best adhesives and sealants in the industry and their marine hull sealants are not exceptions. You can apply it even under the waterline of the hull and it will retain its strength regardless. If you have a sizable breach in your boat’s hull, then this product will make it seem like the damage never happened.

You need to be careful when applying a 3M marine sealant below the waterline because it permanently bonds to surfaces. I suggest that you always use rubber gloves when using this product because it can be a real, literal pain to get it off. The good news is that once it sets on anything that you want to repair, it will stay forever.

This poly-sulfide marine sealant is also pretty durable. It goes without saying that it is extremely weather-resistant and 100% waterproof. Even if you leave your boat tied to the docks for months, no amount of water will seep through the sealant. Of course, remember that because it is a marine sealant, it can resist any kind of corrosion brought about by saltwater.

Even though this non-adhesive sealant is quite strong and durable, it is still very flexible. This capability is important because it enables the sealant to twist and bend with the vessel and remain permanently adhered to the surface. If the sealant was stiff and rigid, it would crack and peel off after just a couple of weeks.

I can’t complain a lot about this product, but you need to keep in mind that once you open its tube, it is crucial to use up all the contents. Even wrapping the leftover sealant tightly in plastic wrap will not stop the contents of the tube from drying up and curing.

3. Loctite PL Marine Fast Cure Adhesive Sealant

Loctite is famous for their super glues and their screw locks but they also make products that fall under the best underwater sealant. This marine adhesive sealant is perfect if you own a small aluminum boat or even a seafaring vessel. It is so strong that it can bond metal to metal but, of course, you should still use metal fasteners to make the joint permanent.

Another thing that I genuinely adore about this product is that it dries in minutes and completely cures in just 24 hours. It is great if you are a commercial fisherman or love to hit the water and can’t stand even one day of not being in your boat. If you use it, you can finish your repairs in the morning and have your boat out on the water by tomorrow afternoon.

You can also use this sealant on the hull underneath the waterline. Properly applied and let to cure completely, it can create a completely watertight seal. Even if you leave your boat on the water for months, not even a drop of water can get into the seal. It also ensures that there will be no mold and mildew getting inside the hull, preventing more expensive repairs later on.

Now, if you do not like leaving your boat with an unsightly patch on the hull, you will love the fact that you can paint over this sealant once it is dry. Just apply enough of this stuff to the place you need to repair, sand it down, and paint over the sealant.

Here’s what I did not like about the product, though its container is so flimsy and the contents are a bit hard to push out, resulting in the packaging leaking. Some people even experienced the tubes bursting open.

4. Star brite Marine Silicone Sealant

One thing I like about the Star-Brite marine sealant is that you can use it on almost all materials you can think of. I have tested this product on fiberglass, metal, and wood, and I have found success using it on certain plastics as well. It can basically work on any material that you might have on your boat.

If you ever need an emergency fix for the hull of your boat, then this product will work. This silicone sealant provides an airtight and waterproof seal, so you can even use it in places underneath the waterline. It is also the reason why many consider it as the best sealant for boat hatches.

Speaking of emergency fixes, you will be glad to know that this sealant can dry completely in under an hour and it will cure in a day. It works great when you need to use your boat the following day, especially if the repairs are on the hull.

Another thing that I like about this sealant is that it is resistant to UV-rays. It does not turn yellow even after months of sun exposure. Also, it will not dry up and crack, unlike other sealants.

Now the biggest problem that I have had with this product is the packaging. The seam that holds the tube together is so flimsy. If you put too much pressure on it while trying to dispense the contents, the tube will burst. You will not want that to happen because cleaning this stuff up was a nightmare.

5. Dap 00694 Silicone Rubber Marine Sealant

One thing that impressed me the most about the Dap silicone sealant is the fact that it has dozens of other uses other than patching holes in the hulls of boats. I discovered that it also has a lot of uses in the home. I have used it to seal the edges of my aluminum kitchen sink, and I have successfully glued on the soles of dozens of shoes.

Now, you might think that just because this sealant can adhere to a lot of different materials, that means that it had to compromise bond strength. Well, it is not true at all. Unless you deliberately scrape this sealant off using a sharp putty knife, you will not be able to pry apart by hand two surfaces bonded by this product.

Because it is a marine-grade sealant, it means that this product makes a completely watertight seal. It means that it will be a great solution when your boat sprung a small leak. You can confidently sail over the sea knowing that you patched up your vessel using this sealant.

Even though this product bonds two surfaces effectively, that does not mean you cannot remove the sealant when you need to. For instance, you just hurriedly applied the product because you were pressed for time and needed a quick fix. In that case, you can scrape this stuff off using a putty knife.

However, I do have a minor problem with this sealant and that is with its cap. If you have plenty of sealants left over, make sure that you wipe the nozzle clean before replacing the cap because the chemicals will eat away at the plastic cap.

6. Sikaflex-291 Adhesive Sealant

I know that most of the other sealants mentioned in this article can also serve as adhesives, but the Sikaflex sealant is a true adhesive that is useful in plugging up holes and filling up cracks, too. This makes this product even more versatile as you can use it to bond to surfaces together.

Unlike silicone sealants, you can sand and paint over this product. It is especially important if you will be using it to repair your boat’s hull above the waterline. You do not want an unsightly discolored patch on the side of your boat. With this product, you can sand the surface until it is smooth then paint over it to make it look like nothing ever happened.

Speaking of boat repairs, if you are an avid boater and you cannot stand waiting a week or so for the sealant you used to dry, then this product is a great recommendation. The reason is that it dries to the touch within an hour. It will also completely cure and harden after a day. It means that you can go back to doing what you love the following day after repairs.

As mentioned earlier, this sealant is not just suitable for boat repairs but also for household repairs. You will even find it useful on potable water containers and it will not leach chemicals.

With that said, although it is a marine sealant, you should not use it on your boat’s hull under the waterline. Theoretically, it can resist a bit of saltwater exposure, but it might peel off if you submerge it in seawater for prolonged periods.

7. Boat Life Sealant Lifeseal Cartridge

If you have a fiberglass boat, you will need a couple of tubes of fiberglass sealants always at the ready onboard. This sealant is specifically for fiberglass surfaces and you do not need to prepare the surface that much before you apply it.

Speaking of application, this sealant is easy to use. You just apply it over the problem area and it will self-level. You do not need to even out the surface using a spatula. All you have to do is clean the surface, let it dry, and then apply this sealant over it.

Once this sealant is dry and left to cure properly, it will leave a seal that can resist saltwater corrosion and block out the UV rays of the sun. Even after years have passed since applying the sealant, it will not turn yellow and crack.

Also, even though you will be exposing this sealant to constant moisture, it will not attract and retain mold and mildew. In other words, you can also use it on fiberglass baths and tubs.

The biggest issue that I have with this sealant is that it is only effective when used on fiberglass. It is not a problem if you have a mostly fiberglass boat, but for anything else, it will not have that many uses.

8. Better Boat Marine Adhesive Waterproof Sealant

This product is by boaters for boaters, which is why you can surely get more than your money’s worth with the Better Boat Store sealant. It has been a couple of weeks since I used it to repair a sizable crack in the hull of my boat and it is still holding strong. Undoubtedly, it will last for many years more.

Aside from being resistant to hits and shocks, this sealant can also withstand the harmful effects of UV rays. It is also highly resistant to saltwater corrosion. I used it to repair the hull of my boat under the waterline and it still looks like it was just laid on for a couple of days.

Another nice thing about this sealant is that it can adhere to almost any surface that you can think of, be it fiberglass, bare metal, wood, and even most plastics. It also makes this sealant perfect for household repairs. I have used it to seal a couple of windows at home and it worked magnificently.

Although I cannot attest to how flexible this sealant will be after a couple of years, I still heard many good stories from other boaters about it. Some of them testified that it has been a couple of years since they used the stuff and it was still quite flexible.

Now, I do have a slight issue about it and that is it takes quite a while to cure. Although it dries after an hour or so, it will not reach its full bond strength until after a week passes.

9. 3M 4200 Marine Adhesive Sealant

As the name suggests, the 3M Fast Cure only needs a short amount of time to cure completely. Unlike other sealants that need a couple of days to cure, this product takes only less than a day. In other words, you do not need to wait for a long time before you can board your boat and hit the water once again.

Speaking of hitting the water, this sealant is suitable for use above and below the waterline. It is a fantastic emergency fix for that unexpected hull leak the day before your next fishing trip. Patch up the damage in the morning and your boat will be ready to go the next day.

Once applied, even extreme weather and the harsh rays of the sun will not be able to damage the sealant. This product is completely weatherproof. Even torrential rain or snow will not damage nor cause it to drop off.

If, after a couple of years you want to remove the sealant and re-seal the damage, you can easily remove the old one without damaging the surface. This sealant comes off cleanly using just a simple scraper. You do not even need to heat it to loosen.

Now, I did have a bit of a complaint, but not with the product itself. I was surprised that the sealant did not come with a nozzle. I know that it would not come with a caulking gun, but it should have at least a nozzle applicator. I had to run over to the hardware store and buy a nozzle for this sealant, which was a waste of my time and energy.

10. GEAR AID Aquaseal FD Flexible Repair

Now, unlike the other products in this list, this marine-grade polyurethane sealant is ideal for use on repairing the gear that you take with you when you go boating. For instance, if you find a rip in your wet suit, you can use it to glue the torn pieces back together.

This repair adhesive cures quite fast, too. If you need to use your gear the following day, you will be pleased to know that this stuff dries in less than an hour and cures into a rubber polyurethane patch that holds permanently in just half a day.

Speaking of curing, once this stuff properly dries and cures, it is completely clear. If you did the repairs properly, you will barely be able to see any indication of the previous damage. I used it to fix a rip on my vinyl camping tent, and unless I look closely, I would not be able to find the patched-up part.

No matter what kind of gear or material you will be working with, I can guarantee that this adhesive can bond onto it properly. I have used this stuff on a bunch of different gear. I used it to fix a tent, glue the sole back on my boot, patch up the inner tube of a bike, and fix a huge tear in a backyard kiddie pool.

However, I noticed that no matter how tight you replace the cap, the contents will start curing. After a month, the leftover adhesive completely dried and cured in the tube, rendering it useless. It was such a waste as there was still more than ¾ of the tube left.

11. Inland Marine USA Inflatable Boat Sealant

Unlike the other sealants included in this list, this one fixes leaks in inflatable crafts and similar items and it does so from the inside. If you have a white-water raft and it already has a couple of slow leaks, you just need to pour it into the craft and it will seal up the leaks from the inside.

Apart from sealing existing leaks, this product will also prevent similar leaks from appearing for at least the next couple of years. It prevents the vinyl from tearing, thus preventing small puncture holes from opening and releasing air.

As mentioned earlier, this sealant can last for at least a couple of years, meaning you can get your money’s worth just from a single bottle. Just one bottle can completely protect a three-compartment raft.

It is also quite easy to use. You just need to remove the air valve, stick the nozzle into the valve stem, and then squeeze the contents inside. Even without reading the instructions, I was able to figure out how to use this product. Afterward, you can let the sealant cure for at least a day and you will be good to go.

Although this product is quite convenient, keep in mind that it will only work for small punctures and slow leaks. If your inflatable snags on a branch and rips, this product will not be able to prevent your raft from ripping open.

12. Sudbury 300 Elastomeric Marine Sealant

If you are thinking of making major repairs on your boat, then you should get the Sudbury elastomeric marine sealant because it comes in a huge 10-ounce tube. This one tube should be able to fill in all the cracks and holes in your boat, and then some.

Another reason why this sealant is one of the best in my opinion is that it dries and cures quite fast. It takes just an hour to get dry to the touch and less than 24 hours to cure. In other words, you can patch up the damage one day, and the following day, you can start painting.

This sealant can also easily adhere to almost any surface. I can even say that it is the perfect marine sealant for aluminum boats I have ever used. I used it on my aluminum boat and it bonded onto the surface readily. I did not even need to prepare the surface other than just cleaning it.

This sealant is also suitable for use above and below the waterline, meaning you can use it to patch up any leaks in the hull. It creates a completely waterproof and airtight seal, so no amount of water can leak inside your boat. Moreover, because it is a marine sealant, it can easily resist the corroding properties of saltwater.

The problem that I had with this sealant is that it is difficult to sand due to its rubber-like texture when it dries. The only way you can smooth it out is by carefully water-sanding the surface.

Who is This for?

Even though marine sealants are primarily for boats, specifically ones that go out to sea, it still has many different uses. You do not need to be a boater or own a boat to appreciate marine sealants. If you like to dabble in DIY home repairs, then you will discover that there is a wide array of products that you can use sealants for.

However, if you do own a boat, you must have at least one tube of unopened sealant in your toolbox (you will learn the reason why it should be unopened later). You cannot predict when you will need to do an emergency patch job on your boat, and you will need a good sealant to ensure that you will at least be able to get safely back home.

Features to Consider When Buying Teak a Marine Sealant

There are lots of different brands of marine sealants in the market today, so choosing just one can be quite challenging. To make your choice a bit easier, consider the following things while browsing through your options:

Material Compatibility

Check if the marine sealant you are thinking of getting can bond onto the surface of the material you are working on. Are you patching up a fiberglass-hulled boat, aluminum, painted metal, or maybe wood? If you can find a sealant that is specifically for the material you are working on, then that’s better.

Sealing Capability

Check the product if it can create a complete seal regardless of the kind of damage you are repairing. If you will be using the sealant to patch up a crack in the hull, you need to choose one that can create a watertight seal over the damaged area. If you will be patching damage that is above the waterline, it would not be much of an issue.

Ease of Application

Most of the sealants you will find come in tubes, meaning you will need to use a caulking gun to dispense the contents. Make sure that the product you are buying comes at least with the plastic nozzle. It would be much better if it also comes with the caulking gun.

Can you Paint Over It?

If you are like most boat owners, then you would not like having visible patches all over the side of your boat. In that case, you should get a product that you can sand and paint over.

Keep in mind that there are some sealants that paint would just not stick onto, like most silicone products. Before you buy a sealant, check the label to find out if you can paint over the product once it dries and cures completely.

Durability

Of course, you need to check how durable the sealant is once it properly dries and is allowed to cure. Most sealants promise that they can stay bonded onto the surface for several years. However, without testing the product for yourself, the only way you can verify the claims is by reading customer reviews.

UV-Resistance

Your boat will spend a lot of time baking under the heat of the sun, so your sealants should be highly resistant to the UV rays. If a product is not resistant to UV rays, it will dry up, crack, and disintegrate when exposed to too much sun. A good sealant, on the other hand, will remain the same consistency.

Mold and Mildew Resistance

Boats spend most of their time on the water, which makes them susceptible to having organic organisms clinging onto them. Included in these organisms are mold and mildew.

Aside from just looking disgusting, they can do some serious damage if they infiltrate the hull of your boat. You will need a sealant that does not just provide a good watertight seal but is also highly resistant to fungi like mold and mildew.

Cost

In the case of marine sealants, it does not necessarily mean that you need to spend a lot of money to get a top-quality product, although the cost is a good barometer. Many brands of marine sealants sell for just a little over $10 that works quite well. That’s not to say that all brands that fall within the same price range are good. You just need to find out which ones are.

Basically, get the most expensive marine sealant that your budget permits. Odds are, you will be getting a great product.

Advantages and Disadvantages of Using Marine Sealant

Advantages

Just like any other repair product, marine sealants do come with their own sets of advantages and disadvantages. Here are just a few of the advantages of using this marine sealant:

It is a Quick Fix

If you need to use your boat at the soonest time possible, you can plug up the leaks using marine sealant even without extensive surface preparation. The good news is that it is easy to use that even a complete novice will not have problems with it.

Does the Job Effectively

Sealants do their intended purposes well. If you need to plug up a puncture in your boat’s hull, squeeze a fair amount of this stuff and it will be all good.

Helps Avoid More Expensive Repairs

Sealants may not be a permanent fix most of the time, but they will prevent the damage from spreading, thereby requiring more expensive and extensive repairs.

For instance, not plugging up a leak in your boat can cause water to infiltrate the hull, and corrode the vessel from the inside. It is much more likely in boats that are in saltwater.

It is Versatile

Sealants do more than just plug up holes in the sides of boats because they also have a myriad of other uses not just for boats. You can use the marine sealant to fix your home’s plumbing, seal window panes, fix cracks on tiles, and a whole lot more.

Disadvantages

As for drawbacks, a couple of those you may encounter would be the following:

Difficult to Store Leftover Sealant

Most sealant brands are so quick to dry and cure that even leftover product that is still in the tube will harden after a couple of days. Therefore, if you will not be repairing anything that requires an entire tube of sealant, just get a small packet.

Can be Very Messy

You can find a lot of horror stories about people putting a bit too much pressure on their caulking guns, thereby causing the sealant container to burst at the seams. Try as hard as you might and you will not be able to completely clean up the mess.

Needs to be Reapplied After a Couple of Years

Unlike welding or patching up fiberglass with more fiberglass, sealants are rarely a permanent fix. Even though some brands claim that they can last for many years, they will still degrade and you will need to remove the old sealant and slap on a new batch.

Care and Maintenance

The nice thing about marine sealants is that you can basically forget about them once applied to the surface. However, if you want your sealant repair job to last for as long as possible, you should keep the repaired part clean. You should also keep it out of direct sunlight.

For instance, if you just repaired your boat and you used a good amount of sealant, it is best to cover it with a tarp to keep it out of the sun. When it comes to storing the leftover sealant, unfortunately, it would not keep for very long once you opened the packaging.

Some people advise that you wrap the tube tightly using plastic wrap and storing it in the fridge. However, that will not stop the contents of the tube from drying and curing over time. Therefore, if you do not have that large of a repair job ahead of you, do not buy a large tube of sealant because you may end up throwing out a lot of the leftover after just a week or so.

Frequently Asked Questions

How to Remove Marine Sealant?

If you need to remove marine sealant, you will find that it can be a bit difficult, especially if it has cured for a couple of years but it is not impossible.

First, you should try if you can peel off the sealant using your hands. Try to pick at the edges of the dried sealant and peel it off whole.

You can also try to scrape it off using a wooden scraper if the sealant is tough.

If you want to make things a whole lot easier for you, you can find heavy-duty adhesive release spray. This product works by breaking down the adhesive component of the sealant, thus making it lose its bond with the surface. After a couple of minutes of spraying on the sealant release, you can cleanly scrape off the sealant from the surface.

Is Marine Sealant Paintable?

Not all sealants are paintable. Take, for instance, silicone sealants. Even if you sand the surface to make it rougher, it will still crack and peel off once the paint dries. Another sealant that you cannot paint over is the kind that leaves a rubberized finish. Technically, you can paint over this sealant, but it will not look good.

The paint over the rubberized sealant will be a couple of shades lighter than the surrounding paint, so you cannot hide the repair job completely. If you plan on painting over the sealant once it is dry and cured, you will need to get one that specifically states on the label that you can do so.

These sealants act like epoxy fillers wherein they dry without any air bubbles inside them. You can also expect these sealants to become solid enough that you can sand them down to stay flush with the surface.

Conclusion

No, having a tube of marine sealant on stand-by in your toolbox is not overkill. In fact, it is a great practice to have, especially if you own a boat. With this, you will always have a way to patch up any punctures or small rips in the boat’s body with relative ease.

However, finding the best product among the many that are available can be a daunting task. Luckily, you now know what to look for in a sealant with the help of this article and you also got a couple of rather good recommendations. With all these details, you will find that shopping for the best marine sealant can get a bit easier.