proper prop for Cape Dory 28 Open Fisherman

[jay crumbie]

Hi Members,
Recently purchased a 1988 CD open fisherman with hardtop. Boat listed at 17 kts and did so on sea trial. Reading specs on boat, I've learned that it is advertised by CD at 23-25 its with Diesel engine of 200 hp. Mine was upgraded with a Volvo Penta KAMD42P with 230 HP.
I'm currently running an 18-20 prop and WOT is a bit over 4100 rpm. Listed WOT for that engine is 3900-4100.
Please, if there are any of you that have experienced a better speed with different props, let me know. I've read that the current sped of 17 is the "normal" accepted speed but am just trying to educate myself as to what YOU are experiencing. If the accepted top is 17kts, I'm fine with that.
I believe my weight is about 8200 pounds with hardtop. Bottom is immaculate! fuel is about 80 gallons. Water is 20 gallons.

So, what are YOU using for a prop and what are your results.
is there a listed performance curve out there?? such as at 1200 rpm I can expect 7kts at 2 gph.
1500 rpm 10kts at 3gph. etc?

have anyone installed trim tabs on this 28 open fisherman? Results? Problems? Type? Cost? Worth it?

Thanks so much for you guidance. The boat (Last Command) is in San Diego. Everyone who sees it loves it! it's a rare boat out here.

Jay Crumbie

[Carl Thunberg]

Welcome to the Board! This is the first post from an Open Fisherman owner. For what it's worth, I have a Michigan 20-16 on my Cruiser. You have a much bigger engine than I do.

[jay crumbie]

Thanks Carl! Appreciate your input.
J

[gonesail]

a guy on cruisers forum said he went from an 18 to 16 pitch in his CD 28 and actually gained hull speed. could not find the original post though.

[jay crumbie]

It was me that went from an 18/20 to 18/16. Appreciate the input.