Hi,
I know this is a topic that comes from time to time.
My C36 has a Universal M35 (30hp at 3.200 rpm). Because we mainly race, drag is an issue.
We being using for the last 10 years, a 3 blades Variprofile 15*11 forward and 15*9 reverse. Now it is time to replace the propeller because starts to be noisy and wear. The Variprofile has very little drag, but under engine is not really very powerful.
We are thinking moving to a Flexofold two blades, the manufacturer has calculated a 16*11. Eureka is from 1991 and has her original bronze shaft.
Well folks, I would really appreciated any comment/experience about the factory diameter and pitch recommendation.
By the way, I also requested an offer for a new Variprofile 2 blades and they also recommend 16*11.
All the best!
Eladio Vallina
C-36 TR EUREKA II
Hull 1122 (1991)
Home port Barcelona (Spain).
Eladio Vallina,
We have hull #1041 powered by the same engine, the M-35. It is my understanding that the original propeller supplied with the boat was made by the : Michigan Propeller Company -Michigan Wheel Corp. ; 15 X9 inches 'Salier' 3 blade model. They have a web site that you can use to calculate the correct sizing. Ours is a propellor used for cruising not racing and moves the boat at 6.1 knots at 2800 rpm with the ZF-10 transmission.
Some of this calculation may depend upon the gear reduction supplied by your current transmission if it is not the original transmission . It might be important to know the gear reduction ratio when figuring the propeller sizing.
Bill Dolan 1990 Catalina C-36 MKI - Hull #1041 'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Charlotte Harbor & The Gulf Islands of Florida
'You are never out of work if you own a boat'
Thanks Bill,
Indeed our original fix 3 blades propeller was 15*9. We change gearbox some 12 years ago and the new ratio in forward is 2:1 while the original was 1.78:1.
So the diameter and pitch are slightly different with the new gearbox. I will follow your advice and see the results Michigan tool gives.
Regards
Eladio Vallina
C-36 TR EUREKA II
Hull 1122 (1991)
Home port Barcelona (Spain).
We first installed a 16*11 Flexofold two blades, engine clearly over pitched.
Flexofold exchange the blades to 15*10, much better as the boat reaches the maximum rpm (3.200) no more no less.
must probably, a 15*10,5, that will reduces rpm by about 100 will be ideal.
Regards
Eladio Vallina
C-36 TR EUREKA II
Hull 1122 (1991)
Home port Barcelona (Spain).