NEW 3 BLADE PROP

[bruce]

I PRESENTLY OWN A CAT 30 W/ XP 25 UNIVERSALI HAVE A 2 BLADE PROP AND FEEL IF I UPGRADE TO A 3 BLADE ILL INCREASE SPEED W/O A SIGNIFICANT INCREASE IN DRAG???ANY THOUGHTS ALSO, WHERE DOES ONE PURCHASE ONE OF THESE 3 BLADERS INEXPENSIVELY????

 

[Jim Nixon]

I have tried this

I have had a 35' sailboat with 23 hp with a 3 blade fixed prop, it was a perfect match it backed up as well as it went forward. I curently have a 30’ catalina with 11 hp engine and I changed from the stock 2 blade to a 3 blade “Campbell Sailer” (it claims to have less drag under sail). I was not sure that it was pitched properly and I spent a small fortune changing the pitch 3 times. The prop walk in reverse is much less with 3-blade prop If I have it to do over again I will get a standard Michigan 3-blade prop and try to increase the diameter to 13” I have been told that it works. As far as buying the prop I suggest that you go to a Prop manufacturer/service as opposed to a retail boat chandlery, they will have a computer program to determine the proper pitch trust them they are in the business price should be around $300.00. I recommend Pacific Marine Propeller 1 800 247-7677. As far as drag under sail I do not race and I feel that the 3-blade is worth the extra drag, some say it is ½ knot. Best of luck, fair windsJim Nixon

 

[Michael McCann]

3 Blade Prop

Bruce;Usually a 3 blade is pitched 2" less than the two blade, and will increase drag up to about 1/2 knot. It is hard to determine unless you race alot against the same boats. I went from a factory 15x11x2, to a 15x9x3, from the Catalina dealer. Pluses are higher speed at same rpm, better backing, slightly less walking, and smoother motoring. Cons are probably more drag when sailing. If you cruise it is worth it.Michael