Outfitting the tandem kayak, Part 6: The seat backs

Sorry to keep you waiting... I hope my technical difficulties are over for a while.  Thanks to Pickle IT for getting my laptop up and running again.

Now that the bulkheads are in place, I turn my attention to the seats.

Touring kayaks typically have some sort of backrests on their seats like the one in Martha's solo kayak pictured at right.  Our tandem kayak came with no such backrests.  I tend to live with such things--I'm a racer, after all, and racers train to sit up straight in their boats--but Martha doesn't like it at all.  And she's right, for a long day of touring is different from the two-hour-or-less races that I mostly do, and it's nice to have some back support in that situation.  So I am going to see what sort of backrests I can fabricate.

My first challenge is to find some sort of a mold.  I have several of these Rubbermaid garbage cans in and around my shop, and it has occurred to me that they are about the right radius for a seat-back.  And the plastic these things are made of won't bond with epoxy resin, so I can lay something up directly on it.

The lamination includes three layers of fiberglass with two layers of Kevlar interspersed.  My technique is to lay the cloth down a layer at a time, pour a small pool of resin on it...

...and then use a piece of minicell like a squeegee, spreading the resin out until it has been absorbed by the cloth.  I keep adding resin a small bit at a time until the cloth is fully saturated.

Here's the backrest lamination after it has been fully wetted-out.  I'll trim off the rough edges after the resin has hardened and I've popped the piece off its garbage-can mold.

If you look back at the picture of Martha's kayak seat above, you'll see a piece of 6-mm rope running behind the backrest.  This rope controls the "recline" of the backrest; it attaches to a cleat up under the cockpit rim.  The tandem boat is already equipped with such cleats, so all I need to do is include some sort of passage for a rope on the backs of these backrests I'm making.  I cut a piece of plastic tubing, hold it where I want it with a clamp, and attach it to the back of the backrest with pieces of Kevlar.

And here it is... a seat back!  I'll be gluing the piece of blue foam onto it.  The foam is cut just a hair larger than the laminate to prevent any sharp edges from digging in.

I pondered several ways of attaching the seat back to the existing seat, but in the end I just stitched it on with some 4-mm rope.  It'll be a while yet before this boat is back on the water, so I'm keeping my fingers crossed for seat-back success.