If by chat you meant chatGPT, this doesn’t feel to me like the kind of question chatGPT is especially well suited for. If you work with a prop manufacturer they’ll be able to tell you the right pitch based on engine and transmission specs. The right numbers could vary based on prop design - a Michigan wheel style prop will have different numbers from a Campbell Sailor Prop, and different again from feathering and folding props.
There are a number of variables that go in sizing a propeller, engine HP, RPM, Torque, hull clearance, prop design, blade count, and hull design to name a few. Incorrectly sized props can impair performance and potentially damage the engine. A prop manufacturer or a shop that specializes in props and drive train parts will provide the best answer to your question.
Maybe I didn't put enough time into my reply. I'm basically saying that the hull speed is all that you should typically attempt to achieve efficiently. An engine with more h.p. will, however, provide better thrust at dock.Hull Speed is not a speed limit. It is an efficiency rating based on the wave length of your wake. As a hull moves through the water, it creates a series of waves. The faster the hull moves, the longer the wave length of the wake. Once the hull's speed is such that the wave length is longer than the waterline length, the hull is effectively trying to drive up the bow wake. The motor or sail, is pushing uphill against water resistance and gravity. That is the point at which power to speed begins to really fall off.
You can certainly get a boat to go faster than Hull Speed, but it takes more and more power until you've added enough power to drive the boat to the top of the bow wake. Then, you're planing, and the energy to speed curve plunges back down again. That is, unless the hull design drives the boat under the bow wake, then you slow right down to the bottom.
-Will
What size and pitch?
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