The boat pictured does not look like a Marcel Belleville design. Marcel almost always used hydraulic steering. His sponsons were usually about 3 to 4 inches deep and his prop shaft generally ran out the lower part of the transom rather than out the bottom like most hydros. Marcell's boats were a "take-off" from his outboard hydros and they ran quite well. He even built an unlimited which was around 30 feet long, powered by 8 mercury V-6's. It looked just like all the rest of his boats. I believe that a lot of the Karelsons were built along the outboard lines and that would be Dave Karelson's design. Ed Karelson designs were generally along the standard inboard designs. Of the three, I would GUESS Dave Karelson, but only guess. Capnzee