RPM setting

[DickB]

There was a thread recently about RPMs and running speed but raised an additional question. I normally run at 1500-1600 on my 44TC. I think this is about hull speed and just below when the turbos kick in. It's my feeling that increasing RPMs simply plows a bigger hole in the water and uses a ton of fuel for no speed gain, until the boat is up on the step. At that point, fuel usage is still pretty heavy, perhaps double the gal/mile compared to hull speed.

Question. At what RPM does the turbo actually kick in and is running all day at 1600 harmful at all to the Detroit?

Dick

[Genesis]

What speed are you making at that RPM?

You do not want to run below where the turbos are on-boost if you are demanding significant power. Usually "hull speed" (actually not quite; a couple of knots above) is in the 1200 RPM arena - 1600 is a bit higher than I'd expect.

[DickB]

The GPS indicates about 8 1/2 knots at 1600. I've run at 1200 before but it doesn't seem like the engines get to operating temp at that RPM. Can't remember the speed.