I have an older Bayliner 22 foot boat. It has been upgraded to a V-8 (350 I think) and a 280 outdrive. It came with two props: a 15-17 and a 16-17. I have been using the smaller one because I thought both were the same. The 16-17 is noticably larger in diameter and surface area of the blade. How do I tell which prop is the best? Does anyone have a similar setup, and what prop are you using?
I can't comment on which prop will be better for your boat, but can comment on testing. In calm water where you have enough room to run WOT you need to compare your top speed and engine rpm with both props. Your engine will have a top rpm that it is designed to opperate at, and there will be a range, like 4000-4200 rpm. If you can get top rpm and get higher speed with the larger prop, it'll be the better prop for your boat. If say the smaller prop peaks at 4100 rpm, and the larger one will only turn 3700 rpm, the larger prop is too large for your boat.
Loading also affects which prop is best. It might turn out the larger prop works well when you are lightly loaded, but with a heavy load you need to drop down to the smaller prop.
The smaller prop should get you on step more quickly and will put less of a load on the engine. So if you'e going to err, erring on the side of the smaller prop doesn't hurt, just don't over-rev your engine.