I currently have a Avon Adventure 560 (5.6m) with a Yamaha 115 four-stroke, at present I get around 39 knots at around 5900 rpm, which according to this site
is about right. We are using a standard 19 pitch 13" diameter aluminium prop. The boat rarely has a heavy load in it, and mostly its just me and my brother in it, were not particualry heavy people either. The boat seems to accelerate very quickly and have no problems in getting it to 6000rpm, I think its got lots more throtle in it as well, although obviously im not gonna push it any further.
Wat prop would you recommend ? Are there any other people here with a simliar setup ? We were thinking of a 21 pitch aluminium (s/s is just a bit to expensive) prop.