On my 3.0 powered boat, I needed 3 props. A 19p, a 17p, and a 15p
The 19p was used for long cruise trips with only 2 people. Could get 41mph at 4600 rpm
The 17p was used when there were more people on board or pulling tubes. Would hit redline before 38mph
The 15p was used for skiing, and...