Prop Recommendations

[p424owner]

Does anyone have any prop recommendations? The yard is not going to reuse the existing prop or shaft, because they have both turned pink. I was not expecting this little issue, based on the results of the survey, and I am considering:

1. Maxprop 3-blade Classic - hugely expensive.
2. Campbell Sailor - fixed, not sure about pricing etc

What is everyone else using? Any suggestions? I have a 17x11 prop.

Ewan

[kevin barber]

Ive got an autoprop-  The boat reaches hull speed under power at 1600 RPM, backs like crazy, saves fuel, and feathers under sail.  Its on the high end of the price scale, but it is pretty awesome.  

http://www.autoprop.com/

Defender is a distributor.

[Trinity]

Hi Ewan,
I have experience with maxprops on my previous vessel.  They performed as advertised, very good customer support.  Price is the only 'issue'.
Regards,
Marc

[Leo]

Kevin,

 Does the feathering prop improve control in reverse? My cutter tends to pull starboard and I have little control other than knowing where the prop walk takes me. Sometimes good, sometime bad!

Leo

[kevin barber]

Yes, but you will always have some prop walk.  The autoprop creates a much better prop shape in reverse than a fixed prop, in fact it is the same shape in reverse as it is in forward, thus creating much better thrust.  You can watch a video demonstration of it on their website.  

The autoprop actually makes the boat walk to port instead of starboard.  However, you should be able to control your boat pretty well with any prop using short bursts of power, then allowing your rudder to catch the water without the prop pulling in either direction.  Just use the prop to create momentum, then put it in neutral to steer in reverse.    With a little practice you will also find that you can also make very sharp turns using this method, you can almost rotate the boat within its length.

[Randy]

I have a 3 bladed Maxiprop on Venture. Does a great job. Great when backing too.

[Lon]

What speed are you able to obtain and at what rpm?  I have hull 402 which has a Universal 5444.  I replaced my Michigan 17/10 RH with an Auto Stream 18/11 feathering prop hoping to achieve better control in reverse.  During last season I adjusted the pitch to be able to achieve as close to 3,000 rpm when full open ( the max rpm recommended).  The pitch was reduced to virtually nothing in order to get to 2,750 rpm. I lost any available punch when needed in current or head winds.  Steerage in reverse was not improved to any great extent.  I am in the process of resizing the prop. Any information on speed and RPM is greatly apprciated as well as other sugestions.  
Lon

[kevin barber]

I too have a universal 5444.  With the autoprop, I get about  6 kts at 1,500 rpm, 6.5 kts at 1,700 rpm.  7 kts at 2,000 rpm.   My autoprop is a three blade 17" diameter.

[Lon]

Thank you Kevin.  Is 2,000 your max rpm?  As I mentioned in trying to achieve as close to 3,000 rpm as posible in order to cruise at around 2,000 -2,500 I had to reduce the pitch.  My top speed was 5.5 knots.  My transmission is a Hurth HDW-10 with a 2.14:1 ratio.  I would be very happy to achieve your speeds.  Any thoughts?

Lon

[kevin barber]

I think you are working your engine too hard.  You shouldn't need or want to rev your engine over 2,000 rpms.   My engine will rev up to 3,000, but it will only get there when out of gear.   I think you should consider going with a higher pitched prop, or ideally a variable pitched prop.  I rarely feel the need to run the engine in gear over 1,600.   I have the same Hurth transmission.  

Next time I am at the boat I will try to remember to look at my spare 2 blade fixed prop, and see if it has the size stamped on it.   Or, you should be able to call a reputable prop shop and they should be able to recommend a fixed 3 blade that would work much better than a 2 blade.  The only issue you would find with the fixed 3 blade is the need for a shaft lock to keep your shaft from turning when under sail.

The auto props' blades spin freely on bearings, a combination of centrifugal force and water pressure automatically adjust the pitch over a different range of RPM's.  There are no preset pitch settings, and no adjustment.  Therefore the pitch will always be maximized for any combination of current and rpm's.

[Lon]

Kevin,
The information that you provided is of great help.  The feathering prop that I have is a three blade.  I don't want to over load the engine with to much load.  I want to be able to run 20% below max RPM and get results like yours.  I have installed a smaller diameter prop with a little more pitch hoping that will work.  I will not be able to test it untill 5-17-08.
I will let you know how I do.  Thanks again.
Lon

[kevin barber]

No problem at all, I'm glad I could help out a little.  I'm a little worried about the smaller diameter prop though.  The smaller the diameter, the easier it is for your engine to turn the prop through the water, which will lead to higher RPM's.   Hopefully you made a pretty big change in your pitch to compensate for the smaller size of the prop.   Did you get a fixed 3 bladed prop?

[p424owner]

Ebay to the rescue. I have secured a used Max Prop, smaller than necessary, but apparently in good shape, for about $800. I am shipping it directly to PYI, where they will resize it to 17x11 and service it for me for under $500. Still expensive, but I will be much happier without the constant turning of my prop shaft under sail, and I could definitely use the speed when clawing off a lee shore.

I will post details when it gets here.

[Lon]

Kevin,

I the time being I am staying withthe feathering prop.  I will let you know how I make out.

Lookfar,  good luck, please keep us posted on your performance.

Thank you all.


Lon

[SV THIRD DAY]

Last Sept before our trip to La Paz we replaced our orginal fixed three blade with a new one..cost $600.  Being so far over the refit budget that I'm past crying and into laughing out loud....I couldn't see spending the extra money.