Martin, one thing I'vwe observed on the fresh water run marine engines I've rebuilt- - - -I don't think I've ever seen one with enough cylinder wear to need to be rebored. A good friend who has spent most of his mechanical career around houseboats and other large water craft like cabin cruisers has expressed the same opinion, and he claims that's because a propeller doesn't put as much torque load on the crankshaft as a mechanical drivetrain does. On the other hand, a boat is running "uphill" all the time- - - -trying to climb out of the hole it's in!
Jerry
