Prop size

[capehorn3]

I have a new DF20ATL on a displacement style hull. I am now into the break-in procedure at +4 hours allowing me 5 min. of full power. I can see I need a different prop with these performance numbers (GPS speed).

RPM MPH
1000 2.2
1500 3.4
2000 4.0
2500 5.1
3000 5.8
3500 6.7
4000 7.3
4500 max RPM

Current prop is factory 10.25 X 9.0

I know this isn't going to be a speed boat but think I need a lower pitch to got to my full RPM range of 6000. Thanks for your time.

[2014DF25ARS]

I trust you have read the sticky thread here re: Adjusting Engine Height and Selecting the Right Prop. There are various "Prop Slip Calculators" available online or as phone apps.

Main point I will make, is that when I was testing some different props for my DF25A, I got some confusing comparison results with a new stainless prop, and I asked a local prop doc to measure my factory prop, which for the DF25A is an aluminum "11 pitch" prop. He measured it using a pitch gauge, and it measured as a 12-pitch prop rather than 11 as marked. So if you are testing non-Suzuki props, I suggest you have your Suzuki prop measured before choosing a non-Suzuki alternative.

[Moonlighter]

I am not sure that the sticky thread re props will be directly applicable here - because the boat Cape Horn has is a displacement hull. Despite that, yes, it does look like you need a prop that gets you at least to 5500 or so so you are not labouring the engine.

I really think you should have a talk with a prop expert who can advise you re the best type, shape and pitch for that motor being used on a displacement hull.

Someone like Ken from propgods.com would be the best. Very knowledgeable.

[capehorn3]

Thanks Guys, yes this boat is different as a displacement hull, we have a good prop shop here in town I will talk to just wanted to get some base line advice.