3 blade prop?

[Leo]

Thinking of going from the 2 blade to the 3 blade prop. I have been told it work better in reverse than my 2 blade. Any input to what size I would need? Have one for sale?

Len

[INCOMMUNICADO]

Len, I think my three blade is 17x12.But it will never back straight with the offset shaft.With the 3 blade you will have the power you need.Allen

[mzed]

It looks like I've got a three blade 17 x 10 on mine.  Power is not a problem, but it's fairly random which way the stern will go when I start off in reverse.  It helps to push the boat in the right direction first.

[Leo]

I checked with a local prop shop and they want $800 for 3 blade fixed prop! Any suggestion on where to find one at a reasonable price?

[swiftibis]

I have a maxprop 3-blade set at 10.4" of pitch, 17" diameter.  Quite a few sailors on my dock have a "Campbell Sailor" prop, and a brand new custom machined prop will set you back 700$ on our sized boat.  The blades look tiny compared to old-school screws but that's why they have such reduced sailing drag.  They certainly have plenty of punch in forward and reverse, and after seeing them in action I believe their marketing.  I've considered selling my maxprop to go to a campbell sailor but due to the shaft nut arrangement I would likely need a new shaft, so I'll just wait until I have a problem. 
Mike
Boracay Star
Pearson 367 Cutter #26

[Leo]

Hi Mike,

Thanks for the tip, I may go that route but was hoping to find a good used one that needs a new home.

Len 

[RayNWanda]

 I had 2 different 365's. The first one had a 2 blade prop, the second had a 17X10 3 blade. The difference in reverse was daylight and dark. The boat with the 2 blade you really had to be careful and start backing earlier. We were in a slip with a bulkhead in front. I never hit it, but a couple of times I thought we were gonna. When we got the second boat, I started backing at the same distance. I had to nudge it forward to get it in the slip. Abracadabra backed down MUCH better.

[Adventurer]

I have a maxprop 3-blade set at 10.4" of pitch, 17" diameter.  Quite a few sailors on my dock have a "Campbell Sailor" prop, and a brand new custom machined prop will set you back 700$ on our sized boat.  The blades look tiny compared to old-school screws but that's why they have such reduced sailing drag.  They certainly have plenty of punch in forward and reverse, and after seeing them in action I believe their marketing.  I've considered selling my maxprop to go to a campbell sailor but due to the shaft nut arrangement I would likely need a new shaft, so I'll just wait until I have a problem. 
Mike
Boracay Star
Pearson 367 Cutter #26

Mike (and group), I'm new to the forum having just bought Audrey (367 Hull #5) and am thinking about a Maxprop since I don't have a shaft lock. They are expensive (Maxprop), but what's a better alternative without the shaft lock and without sacrificing power when backing down?
Trip

[S/V Laelia]

Pog has an old post about the prop sizes and some comments on performance.

[SailingSeaDragon]

Sea Dragon, a 367 with a different underbody than the 365, came with a 2 blade (18Lx10). We sailed for one season with the 2 blade and during that time I was not happy with the handling in reverse or motoring efficiency. I replaced the 2 blade with a 3 blade 17L x 11 prop. I saw significant improvement in motoring as well as improved control in reverse (reduced prop walk and better stopping).

Garner

[Risto and Liz]

We will be replacing our original bronze shaft with a new 1-1/8" SS in the next few months. We currently have a two blade which seems to suit our needs. Is there a compelling reason to consider a three blade? I understand it backs down better than a two blade but is there a performance/economy advantage going forward? I have not had any issue with backing down to date and the pronounced starboard prop walk is something I have found to be an advantage (sometimes 😅). I thought I might pay the prop shop to recondition the 2 blade.
With all the other things we need to do to prepare for an extended cruise. I am not looking for additional expense unless there is a good reason.

[SVJourney]

Ritso,
For an extended cruise a spare prop is something I consider essential.  (Along with spare prop nuts!)
Consider getting a new 3 bladed and throw the 2 blade into your spares locker.

We have a Kiwiprop.  Excellent reverse, much better than the fixed pitch, and it was a noticeable increase in sailing speed with the feathering prop.  Although, I gotta say, the spare prop was only used when the kiwi prop failed one time.  Taught me the value of the yearly lubrication I read about in the manual.

Wayne

[Risto and Liz]

Ok, I got a price of $750 for a Campbell Sailer. They recommend 16x9.5.
Does anyone have experience with the CS? Size and pitch? Effectiveness?
I don't want to spring for a Max-prop so am looking for the best value for a three blade fixed. Local prop shaft that is making our new shaft quoted $600 for standard 17Lx11 3 blade.
Sailing performance is important but by the time we load up the boat with all the gear, my guess is that a half knot either way is not going to make a huge difference.

[PeteW]

Risto,
You never clarified what motor (HP) you have in your boat ? Is it w40? ( HP vs rpm)  I assumed you don't have a 4-108.  Mine's been repowered  with a larger motor and I found a very clean used 17"x 15" 3 blade ($150), which was close to what I wanted.  I based that on the calculations from this tool. Of concern with larger motors is exceeding the tourque rating on your 2:1 RV-10.  Its going to be close with a larger motor per Walter V drive specs. So you should check you v drive for backlash. That's the failure mode, its not bearings that wear out. (pinion shaft splines)

http://www.vicprop.com/displacement_size.php

Don't forget to specify the prop bore. FYI you can shim an 1 1/8" shaft  taper up to 1 1/4" prop bore if need be. It will be hard to find reconditioned props in 1 1/8".

Pete

[PeteW]

Risto, pretty sure your boat is a M50 Universal,  44 HP at 3000 rpm. So you have few extra HP over the 108.

The prop calculator says you need 17x10 for hull speed with those numbers. But if you back your motor off and ask the program to calculated hull speed using a lower RPM and HP it says to use a 17 x 13. The difference is being able to motor at hull speed at 2300 RPM vs. 3000 rpm.  (3K rpm I think is too high for a diesel) This all supports 17x11 as the right choice for the 108. But I believe you have the margin to go up in pitch a little. I believe this allows you to cruise 7+ knots a lower RPM.  Note: I enter the continuous duty HP and RPM from the graph for my engine not the max.

Interesting that this tool calculates HP put to the water for the Pearson 365 hull  at 5, 7.5 and 8 knots as being 10, 33, and 48 HP respectively.

Since the fuel consumption for my Westerbeke is given in lbs  per HP hour. (a railroad term)  My fuel consumption goes from .6, 1.64, to 2.2 gallons per hour at 5 knots, 7.5 knots and running flat out at 8 knots. ( where it goes up by incredible amount)

Very interesting.   Pete