Finishing the Mold

After the last of the glass and resin are finished take it's temperature.
To low a temperature and you risk the resin not setting ant to high and
the mold may warp and also harm the plug.
Wait at least 24 hours then remove from the plug, trim and seal the edges
also sand down any sharp edges. Then polish and wax and wax ...

Reniforcing the mold.

Add 2 or 4 layers of 1.5Oz. mat let it hang over the edge. Then run plastic tubing or some wood down the edge and fold the excess mat as well as some 5Oz. cloth over it and back down to the back of the mold.
After the mat and cloth are in place wet them out with
resin and roll out the air.

First layer of Centerboard mold.

The first layer of the mold is a combination Cab-o-sil (500 ml by volume) and 500 ml of ASHM6253A
(unsaturated polyester resin). Let this gel then add a layer of 5oz. glass and roll out the bubbles, then add two layers 1.5oz. of chopped strand mat then let it cure for 24 hours.

Creating a Centerboard Mold.

Started to make the centerboard mold, using MDF to create a flat surface and 6"X48"X1/2" balsa
as the plug for the centerboard. The shape is a NACA 0010-34 profile.
After the shape is done prime then polish then wax and wax and...

Putting the plug "in" the table to make a half mold.

After the plug is primed and sanded (and primed and sanded ...) I created a table

to drop it into, to create the mold flange. I put the plug on the surface and leveled it
then using a right angle drew the outline. After cutting out the center and making a
close fit I coated the surface with epoxy. Now you can drop (lower gently) the plug in
and level it. To fill the gap I used modeling clay, this may not work for you if you
live in a hot environment. All surfaces have been polished and waxed prior to this point.
But more wax will be need before the PVA is sprayed.

Skinning a Cat (well at least the plug)

The sides of the plug are 4MM ply and the bottom is 3MM that is steamed then bent over the frames and dried. After the moisture is out of the 3MM it is glued and stapled into place.

Attaching Stations to the Strong Back

The stations (frames) are attached to strong back (building table) using a 2X4" screwed to the table at each station. Then the frames are connected using a 5mm plywood that is attached using machine screws.
There is a 3mm wire running down the length of the table and each frame has a 5mm hole in it.
When the wire has a 1mm space around it the frame is centered and can be attached.

This design is an extension of the last design I created
after creating a batch of 18Sq Meter Cats I made for two friends and myself. Those boats where made out of Kevlar with a honeycomb core. They had a high freeboard (22 in) to cut down on the chance of pitchpoll. These boats had masts of between 32 and 36 feet. For this design I decided go with a lower freeboard and a much finer entry, as well as a rounded fore deck. The intension is to build a middle of the "road" boat that will not be targeted for any one condition.

This is to document the build of an A-Cat.