I followed the directions in Building the Greenland Kayak for building the float bags but glued the vinyl instead of getting heat sealing fabric.

The process is pretty easy. Measure the void to be filled with the float bag. You will need the circumference of the hull on both ends and the length of the void. For the SeaPup that was 44″ long, 40″ at the wide end and 22″ at the narrow. I just measured around the outside of the hull for the circumference.

Cut out two trapazoids that looks like this, lay them flat on each other and glue about a 1/2″ strip around the edge. Put a piece of vinyl tubing (I used 5/8″ OD) in the tab and glue and clamp it so it won’t leak. Metal spring clamps with the rubber tip removed work great.

I used the same HH-66 glue thinned with MEK that I glued the skin with.  I would suspect that regular PVC pipe cement would work in a pinch.  One of these days I’ll get around to buying a can and testing it’s strength.

I had a bit of problems with a small leak around the tube. I glued two flat patches to either side and clamped it again. I let it sit longer before I blew it up the second time and it was still drum tight 3 days later.

As you can see in the picture below it does a great job of inflating the voids even when the holes in the frames are small.  Just be careful not to blow it up too tight our you might break the deck stringer.