Covering the Bottom with Ply

Fig 1. - Clamping down a sheet to mark the shape

Marking and Cutting...

Now that the frames and sides are trimmed its time to apply the bottom plywood.  There will be two layers of 1/2" ply installed for strength.  The first layer will be glued and screwed to the frames and the second layer will be glued and screwed to the first.  The first step is to cut a half sheet and line up with the closest frame toward the stem (or front) that will cover from side to side.  From there its pretty simple, just a matter of clamping down the ply and marking the cut where the outside of the side ply intersects the bottom (Fig 1).
Once marked, cut to the line and set aside.  We opted to do all of the cutting at once since there was going to be a lot of glue mixing and screwing down once we started.  We suited up in coverall suits to protect our clothes and skin.


Installing...




Fig 2 - Squeezing bead with Ziploc pastry bag.

Installation was messy, awkward but simple. The epoxy was mixed to a peanut butter consistency using fumed silica and milled fiber for strength.  We used a short cup to fold a quart Ziploc bag in and dumped the mixture, forming a pastry bag to squeeze along the frame edges (Fig 2). 



Fig 3 - Brushing the drainage holes to seal the wood.
Also note the bead of epoxy spread along the frames,
ready to receive the plywood.



We also took the time to saturate the limbered drainage holes in the frames which would be tough to get to once the plywood gets installed (Fig 3).  The plywood was screwed down, one after the other and now we are ready for the next layer of ply.




Fig 4 - Glue spread waiting for next sheet

Next layer of ply was marked and cut the same.  We were sure to stagger the joints so there wasn't a weak spot formed.  Each sheet took between 12oz and 36oz. of epoxy mixture.  This was mixed to mayonnaise consistency with a notched trowel.  The awkward part was just trying to hover over the glue long enough to get the panel lined up before dropping into place.  Fig 4 also shows the previous sheet edge to the right and the pencil mark on the left that was used to line up the sheets as we went along for cutting; as well as, a stopping point for the glue.  We didn't attempt to glue all of this at once.



Filling out the Tyvek suit to its breaking point...

Extending the side angle through the bottom ply...

Just as the title states the bottom ply must be cleaned up by following the side angle.  Not much to say here, no real tricks.  I used a power plane and belt sander to do this.  The following pictures show how this should look when finished. The stuff on top is curls from the power planer. Next up, the keel...