Brian once I get it built and tested i'll post up a full "how-to" thread complete with diagrams / etc. Lexan is the American name for Polycarbonate and there are plenty of suppliers in the UK for tubes and flat 5mm sheet. The end-caps have to be at least 5mm to alow for machining down the inside so it slips into the main WTC tube and you have to cut 3 grooves into the plug to take seals to keep the water out. As far as I know you have to pressurise your WTC before you set off so there is enough air in it to fully inflate the bladder in the ballast system , now the guys across the pond use a type of bottled compressed airbrush propellant for this , BUT , there are only a couple of types that are ok the rest will destroy the O-ring seals sometimes within a minute or so. I intend using nothing but compressed air via a 12v portable car tyre pump that i'll be running off a battery , just to to work out the pressure i'll need once I settle on the size of the WTC.
I'll be using UK sourced components ONLY and I will put up a full list of the source companies and prices as I go. First sub will be the Trumpeter Seawolf then once i've got a few of my fishing boat models built and i've done all the research for the Astute class SSN i'll drawn up plans and scratch build HMS Astute.
Davie