Retrofitting Larger Hatches

I’ve read that the newer, larger Kajak Sport hatch rims & covers can be installed into older British fiberglass boats with the small hatches. Their website says the rims are made of ABS; any problems adhering this into the stock fiberglass hull?

I presume this involves some careful cutting and glass work, but it doesn’t seem beyond the abilities of a careful do-it-yourselfer. Any advice or comments from someone who’s done this (or even some wild rumors and outrageous claims from the friend of a friend who might have done something remotely related to this one time …)?

here’s a job
i bet that they are a bunch of NDK owners who’d gladly sign up for this service!

kayaksport hatches
I used “Liquid Nails” from Lowes to install my kayaksport day hatch. It seems rock solid so far. My boat has an ocean cockpit so I have to sit on the back deck (on the day hatch) while putting my legs in the boat. Unfortunately, the adhesive dried white.

Best Adhesive!
3M 5200 for marine application. Buy the smaller tube because the larger culking gun size does not store well.

go for it
glue and screw or just glue. 5200 is my choice but…takes a while to cure.


So …
… do the Kajak Sport rims have a flange that is glued to the underside of the deck, like a factory job? Or does the whole thing adhere to the top surface of the deck?

The latter, especially if using screws/rivets, sounds like a fairly easy but klunky-looking installation.

the KS hatch is a surface mount. NOT klunky as you might think. the cover does a great job of covering.



so to pu one in you
would have to remove the old hatch rim completley back to the manufacturing point of ZERO hatch just a hole in the deck?


The problem is…
…that the hatch rims need to mounted to a flat surface, so unless the deck of your boat is flat, you’re going to have to construct recesses with flat flanges, as the factories do. If you’re good with fiberglass, it’s certainly possible to do, but I suspect that this is more work than you’re interested in. If you want to give it a shot, there are some wooden boat builders who have made glass and carbon fiber recesses for their boats. You can connect with them at Just post a question in the boat building forum.

Valley hatch rims are designed to be installed from underneath and bonded/glassed to the underside of the deck. Kajak Sport hatches are designed to be installed into recesses on top of the deck, as Flatpick pointed out.

5200 vs 4200
3M 5200 is very tenacious and can be a real ”suka” if you have to remove it. I have switched to 4200 which releases a little easier.

Thanks …
… for all the info, everyone!

Gives me a lot more to go on, and will have to take a closer look at the boat,

Thanks again!

Some thoughts
If the ABS Kajak Sport rim is a bit too big it’s a very easy job to route it down to fit your boats dimmensions. You’ll still have plenty of bonding surface. Plexis ™ is an outstanding adhesive (Methacrylate) and is super, super strong, albeit costly. Urethanes such as 5200 are excellent as pointed out and cheaper. 5200 is messy stuff, so be careful! Clean the surfaces to be bonded well. It’s also wise to fabricate a clamping system that will uniformly apply slight pressure to the ring / oval. Be careful not to squeeze out all the Methacrylate with too much pressure. It doesn’t require pressure to bond. It will eat into the materials and make an insane bond! Plexis is the brand to choose, and they have product that will remain flexible and seal well. Squeeze out can be easily removed with a small tongue depresser. Urethanes can be affected by extreme heat.

Go for it…easy stuff to do.

you can actually grind off the old one down to flat then install the new one on top of the old one. I have found this works well if the old one IS hard to remove. I did a NDK once that tore off a bunch of the fg deck material. d’oh.