3 blade prop1

[Turning Point]

Hey all,
   I am entering the great debate about props.  What about a 3 blade?  Better performance upwind??  I have a 1986 C34 142 with the Universal M25 (21 Hp).  My 2 blade orginial prop slows down to 2/3 kts in a 4' chop in 18 plus winds.  My current 2 blade is a 15 10 1.  Anyone have experience with a 3 blade?  what size?  what brand?
Thanks much,
Denny Dutcher   

[Terry Forshier]

I have the original 3 blade prop on the 1988 Cat 34 #570. I have the MX 25 and the 3 blade pushes me at about 5 kts ot more. It is smoother than a 2 blade and does not show appreciable slowing against a wind or chop. Formerly I had a Yanmar 15 witha 2blade on my old Oday 30. Enen with a smooth clean bottom, new cutlass and the motor running smoothly it was a LOT shakier than this new arrangement . I also have a dripless installed instead of stuffing box. Original mounts. Still   s m o o o t h.....

[Ron Hill]

Denny : You will really note the difference in "power" if you install a 3 bladed SAILOR style prop 15" diameter and pitched to 10".  Look in the tech notes from MANY MANY discussions on the prop topic.   

[sailmed]

Thrilled with 3-blade Gori folding prop on M-35 engine. 

Easy 6.8 kts SOG thru chop out of Annapolis, with a headwind, at a restful 2400 rpm. 
Reverse stops on a dime and leaves you nine cents change.  Folds up to nothing when sailing.  Smooth, silent, no chatter.

Reverse is like driving a car.
Not inexpensive, but it has so many positive attributes, it was money well spent.  Well worth your consideration.

[Ken Juul]

I am very happy with the performance of my Campbell Sailor  www.westbynorth.com   The power and smoothness of a 3 blade with just a little more surface area than the standard 2 blade.  Some prop walk, but better reverse than than the Michigan I replaced. 

[Andrew Harvey]

I switched to a 3 bladed prop that I purchased on this site ( real cheap ) some one was switching to a folding prop.
What a huge difference particularly in acceleration around tight quarters and reduced prop walk.
Andrew   

[Stu Jackson]

If you haven't yet, try a search on "prop walk."

[Jeff_McKinney]

I want to give a "ditto" to Barry's comments (have the same prop). The other bonus is virtually no prop-walk in reverse with the Gori.

[Ron Hill]

Denny : When you look at the advice given by other members you need to factor in that if they may have a MKII with a 35hp engine while your MKI has a 21hp engine.  The only thing that remains the same for ALL C34s is the prop diameter - which should be 15".
If you'd have had a 23hp engine I would have recommend 10.5 inches of pitch, or 30hp engine to 11" of pitch,  but your smaller engine should operate best with a 15" 3 bladed "Sailor" style prop pitched at 10".   A thought.   

[Turning Point]

Many thanks to all.  I will be looking for the 15 10 1 3 blade.
Cheers,
Denny Dutcher
Turning Point C34 142

[sail4dale]

repeat from another string:



     Re: Propellers
« Reply #1 on: June 25, 2006, 02:51:18 PM »     

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I had a Martec two blade on my CAT 30 for years.  It was not too great backing up ... needed a hi RPM burst to start but after that OK.

I've replaced my 3 blade fixed prop on my MkII with a 3 blade folding from Flexofold.  Couldn't stand the 40 pound drag at 6 knots. I got a 15 x 10 and it pushes me along at 7 kts. plus if I want.  I wouildn't argue about a 9 pitch as it would get you to higher engine RPM's but I do get max torque and good speed without smoke.  I have to idla at about 700 rpm or it gets rough.

It backs up like a charm  I love it.

Check them out on line.  The price is reasonable also.