My last boat had twin 400HP gas engines. When I was running at "slow" speed, I'd run both engines at about 1600 RPM to get about 7-8 knots. I could also shut one down and run the other at 2000 RPM to get the same speed. I had Velvet Drive transmissions, and called the manufacturer about this. They replied that it was fine to freewheel them at those speeds. The only problem with locking down a shaft is that you better remember to UNLOCK it before using it, which also can cause a delay in starting it up when you need it. Anyway, depends on your transmission... ask the mfg. I only ran on one engine after I was out where I was pretty free to navigate, so I didn't need to make a lot of hard turns, etc. I'd start the second engine back up before I needed to do any close maneuvering, etc. As far as wear, I'd run one engine on the way out, the other on the way back, keeping them even on time. I saved a lot of fuel just running the boat at displacement speed with both engines, and saved more by running on one. You can estimate fuel usage of two engines at 1600 RPM vs. one at 2000. Of course, I ended up with a single engine trawler, so I don't have to worry about that any longer! -- __________________ Keith Don't be irreplaceable. If you can't be replaced, you can't be promoted.