350 Mariner hull speed

[bud37]

There is most definitely a calculation , but it is based on theory which gives a reasonable approximation for power planing vessels as I understand it. All that will be affected by the hull design etc. No doubt the hull speed and efficiency rise with the increase in waterline length, that is why we heel sail boats over to increase speed in a race etc., longer waterline length given the same power input. The problem is we have power boats with flat aft planing hulls which are somewhat different, IMO.

But in this case there are too many variables for anything definitive. Rpm is affected by sea state, hull/boat design , vessel weight, wind and the big one, props. If you have fuel flow meters that is the best scenario as you can adjust things as you go to see the immediate results of throttle/tabs input while cruising, in mpg and gph.

I can say that the best tuning aid I ever installed with a previous boat was those meters, helped to understand how the stern wave looks at different speeds relating to fuel usage with that boat.

Those numbers are close to what I had experienced on a different boat.