Minicell Foam

I’m looking into possibly sealing off the stern bulkhead in a Pamlico 100 like it is in a Pungo or similar boat. That’s not a crazy idea, right? Flotation AND a dry hatch can’t be all that bad.

I’m thinking minicell foam 2 or 3 inches thick and I know I’ll need to make an incredibly accurate template, but what is the best sealant to use when I’ve finally got it right?

Also, does anyone have any suggestions for the best place to purchace the foam either online or a retail shop?



My Kestrel has a foam bulkhead, sealed with what appears to be regular outdoor transparent silicone sealant. You may need to sand and degrease the area where the sealant will touch the hull.

For the foam, look at either MxMaster-Carr catalog, or

I would also leave the factory foam block, if it exists, in place, since it most likely provides rigidity and flotation for your boat.

is the sealant that was recommended to me for resealing my Tempest foam bulkheads. Comes in a caulking gun tube - it worked just fine.

Bulkhead templates
You should be able to purchase minicell foam at your local paddling shop.

To get an accurate fit for the bulkhead, you might try the method that I used to form the bulkheads for my Pygmy Coho – it works very accurately. You can read about how it was done here:

You can see how well the bulkheads fit in this photo:

btw: a bandsaw works great for cutting minicell foam.

Hope this helps,


online option

I encourage you to try, although Necky
(who made my only non-WW kayak) always insisted that only foam bulkheads done by experts at their factory would be airtight. My rear bulkhead was factory installed, and instead of messing with a front bulkhead, I merely installed a hatch kit and put in tie points for a float bag in front of my feet. I have Voyageur float bags with slide closures, and a couple of them blown up in the bow are completely watertight and give good flotation.

A cheap way out…
is to use the 2" thick blue builders foam from home centers. It works fine. Less forgiving of a poor fit but with calk - who cares.

I did a bulkhead with that but coated the surfaces with epoxy and it’s unbeliebably strong.

The only thing about closing in a cavity, is how do you check if you are taking on water without a hatch? It’s not a bad idea to have a tiny breather hole for pressure in the summer.

Thanks so much for all the great advice and links! When I get around to actually doing it, I’ll be sure to post my results.


Oh, and the Pamlico does have a stern hatch, so I’m not sealing off into nothingness!