How to Build a Kevlar Canoe - Solo

"Installing Ribs, Floatation"

I used a hotwire setup to cut polystyrene ribs (see 2006 ribs for details). They are a little over ½“ thick, 2” wide and 3’ long. I decided to install 7 of them, since this is a solo and shouldn’t need much (weight centered in canoe). I used 6”, 6 oz s-glass tape to cover the ribs – quite a bit easier than cutting them out from leftovers.

I decided to place my ribs 12” apart aft of the portage yoke, and 16” forwards.  Rough up 6” of each rib location for the width of the rib using a random orbital sander, then vacuum and wipe off dust.

The ribs are installed with hot glue.  Place about 4 “globs” on each side of the keel where the rib goes and quickly put the rib in place, working from the keel line to the gunwale line (press and hold for 10 seconds or so).  This is more easily done with an extra set of hands.

Now mix up a batch of epoxy.  I used RAKA 900HP resin (high strength) with 351 (fast) hardener.  It took a total of about 18 oz for the ribs (two batches).  Wet out 3” each side of the ribs, including the rib.  Place the s-glass strip on the rib and smooth it out by hand.  Work out all bubbles with a 2” brush, and finish off with a light once-over using a foam brush. 

As always, get the epoxy out of the pot onto the canoe as soon as possible.  The pot life on this mixture is only about 10 minutes.  If you get it out on the canoe promptly, you have about ½ hour working time.  All that’s left is flotation, yoke, seat and thwarts (at least 5 lbs, probably 6 remaining).

The canoe now weighs 31 lbs.


Once the 'glass has cured, lightly sand the ribs and any rough/raised edges around the ribs.

Cut two teardrop-shaped pieces of ½” polystyrene (I used a 1½“ cut in half), and fit them to the bow and stern so they cover the inside Kevlar reinforcement.  I cut a cardboard template and used a Surform® to shape the plug.

I mistakenly cut the polystyrene on the labeled side, so I was trying to remove the label with a random orbital sander.  It worked great!  I finished the rest of the plugs using the sander instead of the Surform®.


I roughed up the inside with 100 grit sandpaper at, and above where the plug will go.  I then cut a piece of 6 oz s-glass from the leftover scraps, 1” bigger all around than my template.



Using the same epoxy, put a fill coat on the ribs, covering any sanded parts.  Go over the whole works with a foam brush.


This canoe now weighs 31¾ lbs. The yoke I’ve got in mind is 1½  lbs, so with thwarts, I’m looking at maybe 35 lbs?


Home    Back    Next