I have a Sunseeker superhawk 43 with 2x Yanmar 480 hp, twin disc gear 1.54-1, arneson asd8 with Rolla cleaver's 21,25 x 28. The boat goes 47 knots @ 3400 rpm's. The speed is the same even with a full tank of gas , water, and 10 persons onboard. I think this is the max rpm the engines should be able to reach. The boat feels and looks very bow heavy. The hull is in the water from the thruster and all the way back.
Sunseeker also delivered the same boat with volvo d6. With new d6-400's the top speed are 45 knots, and the boat goes much higher with the bow.
I feel the yanmar/arneson version should be faster, passing 50 knots...
I wonder what to do. I guess the boat needs more bow lift to get the hull out of the water even if it has a stepped hull. The yanmars have more torque than the d6.
Will roundear style propellers generate more bowlift and make the boat faster? If so- what type and size?
Will more rake help?
Or should I think about modyfying the liftingstrakes ? speedrails ?
Any ideas will be of help!

i would contact bblades....

The round ears have more blade area for carrying the hull. Hering builds the ones I run.

Tell them who made you the original round ears for you Mr Vogt. And how well they ran till those old castings gave out. LOL

Definitely use round ears. We can make you some from cleavers if needed. The boats performance numbers and personality help to make the determination.

Brett

I heard they built a few of these with the surface drives and the boat is incredible. Know if any made it to the US? I only see ones with the stern drives...

I actually imported one from Finland in 2021. Have it here in Tampa, FL.
It truly is an amazing boat with the Arneson’s. Only 6 of them made with this engine / drive combination.

I have a set of Rollas.
They have an incredible amount of cup and are very thick.
These are 27 pitch and I can`t turn em past 4500rpm.
I can turn a 29 pitch mercury 4 blade to 6200 all day.

I was going to try them on the 6`s but I found a pair that might be better.
$6k takes em. I spent $2k at FJ in loto to take out some cup and make em perfect but they still don`t pull past 4500rpm.

$6K takes em. 18" diameter

With all the really great advantages of a surface drive I don't believe creating bow lift is one of them. When I had my NXT 382 formula we came into haulover with 4 boats. I had outdrives the identical 382 with arnesons was behind me. I trimmed out a bit to lift the bow and stayed on plane, probably just at 30 MPH. The arneson boat behind my saw what I did and tried kinda the same. Trimmed out a bit and stuffed the next 3 bumps. Blew open his hatches and drowned the interior...Gasp.
I have been in a 50 superhawk with triple yanmars. Great ride. I would seem to think you are propped either perfectly or under a little. Only way to tell is spend lotsa bucks.

The Diesel engines seem to wear prematurely when run over 90% load. That’s typically what they target on new boat builds.

Im assuming your props turn out?