Some of the older Force outboards were actually rated at both. They "used to" put a tag on the engine. I recall seeing an older 50hp Force that was rated at 35 prop hp! I can't swear to it but I believe they still rate at the powerhead (oxymoron calling the upper end of a Force powerhead) <br /><br />Bob
ALL of then used to rate them at the crankshaft. In the late 80's, I think it was Merc who used prop horsepower as a selling point. It workked, and slowly but surely, the rest of the industry folowed suit.
12Footer is right all but Force. That line was never converted. Now that Mercury has dropped the Force line, we will never know what they truly put out at the prop.<br /><br />Ohh well. <br /><br />Craig