Once I had the tail template finished I tidied up the plywood base and cut out the templates from mdf to make a form for the buck I am going to use to make the fibreglass seat from.

 

I fixed the MDF formers in place with good old fashioned glue gun glue, that stuff worked like a charm and is surprisingly strong. Once it had cooled down I filled the mould with polyurethane builders foam. 

On retrospect I used far too much, the foam doubled again in size from what you can see in the photos, needless to say it was a complete mess, and this stuff will really stick anything to anything!

Once this cures you can start to trim it down and shape it.