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Gorilla, Duct or Flex Tape – Which Is Best Underwater?

Mark Armstrong
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When you’re trying to find tape for use in watersports and on watercraft it can be difficult to know which one to choose. You need it to be resistant to water and tough enough to stand up to more complex conditions.

There are several brands of tape that claim to be ideal for the job but which one is best? We’ve looked into the different types to analyse flex tape, duct tape and Gorilla tape to find out what they are and what they’re good for.

Quick Answer: Gorilla tape (although there are dependencies – Read on for more)

What Is Duct Tape?

Duck Brand Waterproofing Tape, Silver, 1.88 Inches x 10.9 YardsPin

Duct tape (sometimes called Duck tape because of the Duck Brand) is a durable tape that was originally designed to seal ammunition cases for the military during World War II. Because of its versatility and ease of use, it can be found in most homes across the country.

Often silver or black in color, duct tape can be easily torn off its roll, so you don’t need scissors to cut it, and it has a water resistant top layer.

What Is Gorilla Tape?

Gorilla TapePin

Gorilla tape is a brand of duct tape that is designed with a double strength adhesive and a reinforced water resistant backing. It is also built to stick to a wide range of materials, including wood, brick and stone – that you’ll probably find other types of tapes may not always stick to.

Similar to regular duct tape, Gorilla tape can be torn instead of requiring to be cut with scissors. It is also UV resistant and can withstand extreme temperatures.

What Is Flex Tape?

Flex TapePin

Flex tape is a rubberized tape that is designed to be flexible enough to stick to all sorts of shapes. It claims to be waterproof and have the ability to stick to wet surfaces, even holding its grip underwater.

It’s designed to seal out air and water, sticking to many types of surfaces. However, it’s not recommended for use on plastics and for certain other materials, it may not stick right away – requiring at least 24 hours to take hold.

Gorilla vs Duct vs Flex Tape: Which Is Most Waterproof And Best For Underwater Usage?

While all of these products are designed to be resistant to water, you may find that one works better than the others, depending on the type of repair job or damage protection it’s for.

Duct tape can be a handy product to have with you in the event of any emergency repairs .

But Gorilla tape may be better for underwater use.

Gorilla tape can have the durability for acting as a keel guard on the hull of your kayak, giving it that extra level of protection if you’re dragging it along the ground. Because of its extra strength adhesive it can stay put in wet conditions, possibly even when the surface may not be completely dry to begin with.

Video: Gorilla Tape Kayak Keel Guard Really Works! – Test Results

One thing that may impact your decision is that when Gorilla tape is removed after a long period of time, it can leave behind some residue from the adhesive. This may be difficult to remove but acetone can be helpful in getting rid of it.

Flex tape, while claiming to be waterproof and flexible, states on its packaging that it won’t stick to certain plastics or water repellent/waterproof materials. So this may not be the best choice for plastic based vessels.

How To Apply Tape To Your Boat

In order to make sure your tape sticks to your vessel, it can be a good idea to clean it so that it’s free of any oils or dirt, as this can affect how the tape will stick. It can also be beneficial to make sure the area is dry before you apply the tape.

Sticking with Gorilla tape (no pun intended), apply the tape carefully, making sure there are no air bubbles or creases as you stick it down. You can use a tool to help you, such as a spoon or credit card, just to press out any air that might get stuck between your vessel and the tape.

Video: Kayak and Canoe Keel Protection with Gorilla Tape (Fishing Kayak Rigging)

You can use a hairdryer or heat tool to set it but it’s not always necessary.

Over To You…

What are your thoughts? Have you used any of these tapes for a repair job on your boat?

Tell us about it below….and if we missed something, make sure you drop a comment.

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Gorilla Tape vs Duct Tape - Which Is Better Underwater (for kayaking and boating) - Pinterest ImagePin

18 thoughts on “Gorilla, Duct or Flex Tape – Which Is Best Underwater?”

  1. used flex tape on pool bottom liner to patch small tear only to see no glue on it once it hit the water and float to surface false advertised

    • Chip, same here! I’m dissatisfied with flex tape too. They show it on the commercial with the whole bottom of a boat done in it. They must of put a torch to it to make it melt together first! Tried to fix the bottom of a pool, dried it well. Couldn’t get it to stick, water proof duck tape worked and a lot cheaper.

      • You clearly do not understand the power of Flex Tape, FLEX TAPE is a super strong, rubberized, waterproof tape that can patch, bond, seal and repair virtually everything
        FLEX TAPE is specially formulated with a thick, flexible, rubberized backing that conforms to any shape or object
        FLEX TAPE can be applied hot or cold, wet or dry, even underwater
        FLEX TAPE instantly seals out water, air and moisture to create a super strong, flexible, watertight barrier
        FLEX TAPE is extra wide (4”, 8” & 12”) to quickly cover large cracks, gaps and holes
        FLEX TAPE is UV resistant, environmentally friendly, VOC-free and has a wide temperature range so it can be used in extreme weather conditions.

        Sharon you clearly have not done your research, young lady.

        • Sob,

          Can you explain what Sharon did wrong? Watching the adds it seems you can just slap it on and it works. You imply it is great and can do everything and Sharon has just not done her research. So can you explain what research is needed to make sure the product works as advertised?

          My car got hail damage and has huge holes in the roof I need to fix while waiting for insurance so if you can help that would be great.

          Thanks Chris

        • It didn’t work for me either. I tried to seal a crack next to a window casing. I sprayed the flex-seal on the crack and it was still letting moisture to get through. I sprayed another entire can and it still leaks.


    Gorilla tape worked great on my RV awnings Constant Houston TX winds created a three foot tear in the fabric of the 16 ft slide awning on my travel trailer Patched it on both the top and the bottom of the fabric five years ago. Still holding strong! Also used it ion a Bimini top for my pontoon boat in 2012. That has over time slid a bit allowing the fabric to move apart some although it is still holding preventing the tear from getting longer. Plan to remove the tape in the spring and replace it. This time I will use a hair dryer to “set” the tape. Yea for gorillat tape!!!! Saved me nearly $1000 for a new sunbrella Bimini cover and fabric for 2 slide out awnings. Not including labor costs for the awnings.

  3. I’m curious to know if Gorilla Tape would hold up temporarily on one of our pontoons that has a couple of small holes from rocks at the slip where we had it?

  4. In my concrete slab there is a leak in joint. What kind of tape I can use in that rough surface. Is it stick in wet surface and cold weather?

  5. Flex tape can be great if it’s used right and on the right materials pool liners are not one of them especially if you try to use it under water. It will not work. The best thing to do is to put flex tape over it and then duct tape over that to hold the flex tape on the liner for 24 to 48 hours then you can take the duct tape off and the flex tape will be sealed secured.

  6. Flex tape is worthless, even if sob says otherwise. If you use it properly it does work, however the fix is only temporary! Gorilla tape works better and on more surfaces and in a wider range of conditions!

  7. I tried FlexSeal Tape to fix a Vinyl liner tear 4″ under the water level of my Inground pool. Once the adhesive contacted the water, the original stickiness totally disappeared. I held the tape against the pool vinyl liner wall with good pressure and no luck. I felt the underside of the tape and no adhesive stickiness!
    The marketing hype should be truthful and complete. If the adhesive loses its strength immediately, taping over it with something else will not help.
    Questions should be answered directly and clearly, such as does it work if applied underwater on Vinyl in “SALT” or “CHLORINE” water pools – not fresh gutter, pipe or hydrant water. Also, some Google sites used the same exact videos for 5 different types of tapes, so you can’t trust all internet sites.
    As one customer wrote, the many videos showed success, but FlexSeal tape did not work at all underwater to fix my clean submerged vinyl liner. The same tape did work above the water line however, but the edges did begin to curl after a few weeks.
    The answer via 5 tests for FlexSeal Tape underwater is NO!
    So I will try Gorilla Underwater Tape next.


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