I don't have a great deal of knowledge other thaN the research I did on Trawler Yachts before I bought my own Trader Trawler yacht last year. www.tripsailor.com/Carlina.
The Colvic model that I viewed a few times was a Colvic Beta. The length was I think about 12mts. Had twin volvo engines and it seemed to be a very substantial craft. Happy hunting.