View Full Version : Setback wonderings

08-03-2001, 09:53 AM

Increased my setback to a total of 12 inches this spring. I have a Phantom 25 & Promax 300. CMC powerlift. Boat weight is approx. 2300 lbs with engine.

Best speed with CMC only (5.5 inches setback) was 76 mph with a Chopper II 26 inch at 6.000 rpms. With a A45 Tempest 25 the speed was 74 mph at 6.100 rpms.

With the new setback, the speed increased to 78 mph with both props (6.200 rms). However, the boat is a handful to drive at high seas, and I decided to pull off the extra setback when I landed on the transom in 70 mph.... despite bowtank and trimtank. So now its back to daily life again... only two weeks close to heaven...

I will try to add a 2 inch spacer (CMC) and see how the boat reacts. Is it possible to mount the 2 inch spacers between the engine and powerlift? Its impossible to mount it between the powerlift and transom, since the transom is 5 inches thick...

Have anyone of you tested Ocke Mannerfeldts Speedrails (the designer of Batboat)? They create bowlift by pulling the water downward from the strakes.

Cheers, Toffen G - Norway