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 Post subject: Wanted Fixed 3 blade prop
PostPosted: 26 Aug 2009 10:06 
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Rail Meat

Joined: 27 Apr 2008 18:41
Posts: 23
does anyone have an old fixed 3 blade prop laying around after upgrading?
Our 2 blade feathering gentleman's racing prop is just not cutting it, we need the family station wagon prop.

Drop me an email to:

j.a.m.e.s.c.l.u.b.l.e.y AT gmail.com (remove the dots before the @)


 
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 Post subject: Re: Wanted Fixed 3 blade prop
PostPosted: 28 Aug 2009 07:45 
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Skipper

Joined: 29 Dec 2006 09:38
Posts: 656
Are you sure you want a three blade fixed? you will lose .7 kt of speed when sailing as that is a lot of drag. The original equipment is a two blade and I found it was fine (if a bit overpitched for the W50). I have an old one here and probably others do as well.


 
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 Post subject: Re: Wanted Fixed 3 blade prop
PostPosted: 31 Aug 2009 08:51 
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Rail Meat

Joined: 27 Apr 2008 18:41
Posts: 23
Thanks for the reply and no I don?t really want to lose .7 knots of sailing speed BUT we cruise about a 100 miles from south FL to the Keys or Dry Tortugas and unfortunately we seem to motor more than sail for lack of wind. We have the w40 with a 2 blade feathering and barely if even get 5 knots making the 100 mile trip awfully slow.

I guess ultimately we want a 3 blade feathering prop but don?t want to spend the $ right now.

Does anyone know/have the original prop supplied with the w40, was it the same as the w50?
What kind of speed did it achieve?

I guess at this point we are looking for the most speed for the least $ and not so worried about sailing performance.


 
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 Post subject: Re: Wanted Fixed 3 blade prop
PostPosted: 31 Aug 2009 13:41 
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Skipper

Joined: 27 Oct 2006 10:32
Posts: 827
J,
That's awfully slow.....I have a W40 with a two blade folding Martec prop and I can easily achieve 6.5 knots motoring at around 2200 rpm's. The speed is measured through my gps.
I would guess that your prop could be out of pitch or you are loading your boat down too much with beer Snicker Cheers


 
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 Post subject: Re: Wanted Fixed 3 blade prop
PostPosted: 01 Sep 2009 07:54 
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Skipper

Joined: 21 Oct 2006 15:36
Posts: 268
J,

I would guess your current prop is way underpitched. I can give you some empirical data from my W50, which I think has similar performance charcteristsics to the W40 (W50 achieves 42 HP at 3200 RPM). I also think my transmission ratio is either 1.8 to 1 or 2 to 1. Literature states both, but I haven't checked.

My boat had the factory provided 16" 2 blade prop pitched to 14". It was way overpitched. I could easily cruise about 6.5 knots with the engine at ~2000 RPM. I would achieve ~ 7 knots at 2400-2500 RPM. I didn't dare to try to run the engine over 2500 RPM (too scary).

Last winter I had the prop repitched. It was actually 13.5" pitch. I had it re-pitched to 11.5". I gained about 300-400 RPM. At 11.5" pitch I can now cruise at ~6.5 knots at 2300-2400 RPM. Now, I don't dare to try to exceed 2800-2900 RPM.

Given these data, I would estimate that 2 blade 16" diameter prop with a 9" to 10" pitch would be optimal for the W50.

If you decide to get a new prop, these data may be useful to the prop provider.

Hope this helps.

Jim
Odyssey, #191

_________________
Jim Voelxen
Odyssey #191
Home Port: Osterville, MA


 
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 Post subject: Re: Wanted Fixed 3 blade prop
PostPosted: 01 Sep 2009 16:07 
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Rail Meat

Joined: 27 Apr 2008 18:41
Posts: 23
Well thanks guys this is great information and has given me a glimmer of hope for our existing maxprop.
Now, how do I repitch it underwater? I hear it is possible.

James


 
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