JEM Watercraft

sot and sink conversion
I did this simple little sketch a long time ago but might give some ideals.



any hull that is stable and wide enough,needs two sealed bulk heads. two scupper hole in the foot well area that are sealed off with two plugs when paddling as a SINK

Block of foam cut to fit inside the area between the bulkheads fit to inside hull.
Carve in seat and foot wells ,very easy to shape with a wire brush on a drill,drill a 1/2 hole from the low part of the seat at an angle to the foot wells. This will drain the seat

In the foot well drill and install two tubes extending below the foam about an inch glue in then install o rings on the part sticking below the foam.
When you want to install to change yak to a SOT remove the plugs from the hull inset the foam plug ,plastic scuppers below the foam with o rings will slide into area where the plugs were.
Wala a sit on top .
The foam can have a coat of epoxy to seal it.
Red neck enginering
Ron

Can't you glass foam also,like when they build those overhead consoles in glass boats

Mike

I see what you mean Ron. Sort of creating a "plug" to fill the volume. That's a pretty clever idea. You can glass closed-cell marine foam.

Expanded Polystyrene (Styrofoam) doesn't get along with epoxy and melts with polyester resin.

I thought you could epoxy most foams without to much problem,you can paint foam with latex house paint and the go over it with polyester ,I have done that.
Ron

Styrofoam doesn't work out so good with bond strength.

Even with the blue insulation foam, you have to remove that outer skin to get a good bond.

But if it's just a "gap filler" and has nothing pulling on it, then the need for bond strength significantly decreases.

Us Composites sells a two part marine foam.