I have tried looking for the start up method on utube but at the moment i an unable to find anything.
It is like a large "O" ring that goes between two pulleys
One on a starter motor and one in the prop shaft (see quick sketch)
I have seen a nipple or tube brazed to the silencer part of the exhaust system.
As i have mentioned i don't know a lot about this type os system but the best guys to help you with this would be the guys that run the fast speed boats.