Hi and thanks for the replies. As far as http://www.papertigercatamaran.org/ goes Ive previously had a really good look around the site and have been unable to find any good shots or drawings of how the boom is rigged. If you can find them you are doing better than me...
The main sheet tail, Jake, whats a "sheave"? Its not in the online sailing glossary's Ive looked at.
This image shows my question more easily I think. Can you redescribe what you said in your post in relation to this pic? Thanks guys for the help!