[Fr. Frank]

Propeller was inadequate. It is a Mercury Trophy Plus 4 blade 13.75"D x 21"P 4-blade, part # 48-825934-21 .
Propeller has 4 1/2" ventilation holes in the outer hub to allow the motor to spin up to high rpms quickly.

Max speed with average load of 6 people, full fuel, plus fishing gear, etcetera, was 33 mph @ 5150 rpms.
(Same prop produced 34 mph @ 5300 rpms with one person, lightly loaded.
Cruise with this average load was 26 mph @ 4500 rpms.

BAD NEWS: I was unable to keep the boat on plane below 4200 rpms/22 mph because of propeller ventilation causing a loss of thrust.
Time to plane was nearly 12 seconds.

On two previous tests, with just myself onboard, the prop performed okay. But the right prop also has to perform well with heavy loads and in adverse conditions. I think this prop, with the ventilation holes plugged, would have been perfect with a 115 hp Optimax on my hull. Unfortunately, I have a 90 hp Optimax.

I have a pretty good idea what prop style/size I need. I just can't afford it.
I think a 13"D x 18"P 4 blade with moderate, slightly progressive rake, and moderate cupping on the backside of the blade, and little cup at the blade tips would be about right.
I really like the design of the SCD4 by PowerTech. It can be seen on the last page of the "D Class" prop catalog from Powertech. PowerTech D Class props