Water proofing a nylon dry bag

I have an Old Town Otter with the built in screw hatch and dry bag. I always thought that the bag was water proof until this past Sat. I took a family paddling and one boy just couldn’t seem to get the hang of keeping the open side above the water. When I got home and was cleaning the boats up I noticed the bag was holding water. The top was still rolled down. I removed it from the boat to dry out. Can I use something like Thompson’s water seal on the nylon?

Thompsons is just a wax and is a terrible waterproofer.

If it is a removable universal bag, I would just replace it with a good one.

Is water getting through the fabric or around the seal/neck?

If the fabric, maybe scotchguard would help, but I would never trust a dry bag that leaked at all

Roll down dry bags are not terribly waterproof, no matter the material. If the roll part was submerged, it is quite possible that the water came in through the roll itself.

One thing you could do would be to fill the bag with water and see if you can see where it is leaking from. That will give you a feel for whether the material is just not water proof, it is leaking in spots, or it was leaking through the roll. The fix for each of these is different.

Just looked, does not seem to be replacement part on Old Towns web site. Can you tell if just the dry bag could be replaced or that plus hatch cover?

If just the dry bag you may be able to work around it with gluing in one of the right diameter.

If that is not possible, you could prevent awkward amounts of water from getting in by getting something inflatable and sticking it inside the failing dry bag. Imperfect but…

It appears that like for many, Old Town needs some time to get their operations back up to snuff. They are short on boats right now let alone parts.

As long as your nylon is still strong and in good shape, you should be able to re-waterproof it. After doing some online research, the following seemed highly recommended. I bought some for a tent and for the original nylon cockpit cover on my sea kayak. The nylon cockpit cover leaked water into the kayak after a rain when a big pool would develop in the middle/sag area. After applying the Starbrite, I suspended the cockpit cover over a big bucket and filled the sag area with water. After sitting for most of a day there wasn’t a single drop of water in the bucket. Your results may vary but it worked well for me. You can get it off of Amazon among other places.

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Note that the Starbrite spray is “incompatible with polyester or urethane backed fabrics.”

Depends on what you call waterproof.

Note that the Starbrite spray is “incompatible with polyester or urethane backed fabrics.”

They make a number of different formulas, including a water-based formula designed to not dissolve things like urethane coatings. If in doubt about what is best for your particular fabric, call their tech support number for a targeted recommendation: 954-587-6280. I have no affiliation with them, I’m just a satisfied customer.

I use their product in my neo skirt, deck bag, and others things no problems for years. I’ll look what it is later.

I assume that you have already called Old Town. If they don’t have the part, ask for a part number and search for that online. There are probably a few dusty parts kicking around in a warehouse somewhere.

Thanks for the tip. I have several older accessories for a Feathercraft kayak with failed coating I would like to salvage, including the same sort of dry-bag type hatch inserts. I’ll look into the Starbrite products.

I finally got time to fill the bag with water. I let sit in the tub for 4 hours and not a wet spot on the outside. I guess the water got in through the rolled top. It was holding water when I removed it from the boat. I am going to stop by Academy and pick up a bottle of the Starbrite waterproofing.