Do the rudder and stab cores the same way.

For the turtle deck cores, these are a PITA.

I have started using polyurethane for sheeting these parts. However, there are a couple of things you need to know or you will mess up big time.

First, when using polyurethane for sheeting, use ONLY fresh glue. Use elmer's ultimate, and make sure you have JUST opened the bottle. Why? because this stuff thickens as it's exposed to air.

First wet the outer side of the Tdeck skin with ammonia and water.

Flip the skin and weigh out 15 grams of polyurethane.

using a spreader, spread the glue into a thin layer on the skin. It will appear almost dry, but that's ok. If it looks wet or shiny, there's too much glue and hence, too heavy.

After the glue is all down, soak up any excess because it doesn't evaporate, it's there to stay forever.

Place the cores in the shucks and weight them down. Use folded poster board, playing cards, clamps and/or weights to make sure the skins are contacting the cores and there are no gaps. This can be tedious the first time you do it, just be creative here. The moisture from the wet skin will kick the glue nicely so don't spray it.

let this cure overnight. When you remove the sheeted cores from the shucks, if the skins are still wet the core will be slightly bowed. Don't freak out, let it dry and it will assume it's normal shape.