THE BLACK ART OF PROPELLERS
as a start all OBMs have a wide open throttle (W.O.T.)rev range, your boat should be propped so your W.O.T.goes into that rev range not above or below,if you rev over the W.O.T. range you are stressing the P.H. if you are at W.O.T. but under the W.O.T. range again you are stressing the P.H.it would be like starting the car in second or third gear, to prop a boat can be frustrating , to get the optimum performance its a question of do i raise /or lower the engine on the transom, do i use a stainless prop,an alluminum prop or if available a plastic prop. With a stainless prop you can mount the OBM higher,(cavitation plate above the bottom/keel of the boat),an alluminium prop level with the btm of the boat , at the end of the day the finall test is on the water, does it get to W.O.T. Does it chine dance? Does it feel good and safe to use?That in a nutshell is the black art of propellers good luck!