Whilst out for a run on Sunday we had the opportunity to run the boat flat out (Not many of those opportunities have presented themselves this year....).
So running flat out (WOT) gave me 5400RPM, and around 25 knots. (I was expecting around 28/29 knots, but end of season dirty bum could possibly/probably account for lower speed than expected).
Checking the specs for our engine (2014 Suzuki DF115) gives us a 'recommended operating range' of 5000-6000RPM.
The prop is aluminium, although I don't know what size it is, and can check this next weekend, and has been on the boat since new in 2014.
We are out and out 'cruisers' and are not too bothered about high end speed, but being an engineer I like to meddle and make sure things are 'as should be'.
Do the numbers sound OK to you for a boat that is purely used for cruising? Or would you think it needs further investigation and maybe some fine tuning in the prop department? Could a different prop give us better fuel economy for our usual planing speed (16-18 knots @ 4000-4200 RPM)?