I’ve been doing a lot of research on holeshot/water skiing and would like to change from a 3 blade to a 4. I also would like greater control at lower speeds. We don’t have a system where I live that you can borrow props and test them out, so trying to get this right first time (if I can!)
Boat is a 2001 Maxum 1800SR. I have an Alpha1 gen2 1.8gear outdrive connected to a Mercruiser 4.3 LH 1996 engine. Engine Manual Says MAX RPM at WOT should be 4400 to 4800.
Out on the water I get exactly 3000 RPM (not a typo!) at WOT according to the dash RPM meter with speed roughly 40MPH. They are newish gauges and do not know if they were calibrated correctly?
Two adults on the boat, a full fuel tank and nothing really extra in weight. The current prop is a Solas Aluminium 14.3” with 21” pitch SOL1511-143-21 which was on the boat when I bought it. I genuinely feel this is over propped in some way.
Couple of questions after a few weeks of research on here and youtube:
- I feel that a 21” pitch at 3000 RPM should be performing a little better than 3000RPM? Shouldn’t it be up in the 3800-4000 region?
- Should I buy a manual tachometer and check the belt?
- What size pitch should I be aiming for if I do get a 4 blade? I read every inch in pitch roughly equals 150-200RPM give or take…. and to also drop 2 pitches going from a 3 to 4 blade
- My gut says 15” pitch on a Solas 4 blade? Don’t seem to see any lower than 15 at the local shop.
Would love to get a stainless steel but feel I should “try” an aluminium first in case I break it (again!)
Many thanks as always!