[C320-list] folding props again

Thu Mar 30 17:04:37 PST 2006

The difference in drag under sail between a two and three blade folding prop is insignificant (folded is folded). A three blade does give more torque (bite) for a given size and it typically will run with a little less vibration because the weight is more evenly distributed around the center of rotation.  Some resonance vibration at certain RPMs seems to be endemic to all folding props, probably because of moving parts. As Dick suggests, the three blade folders work better if you do a lot of motoring or encounter heavy seas. 

  BTW, I'm very happy with a 3 blade Gori.

  Walter Burnett
  Selkie #887

"Richard A. Walker" <dickwalker at att.net> wrote:
  On the left coast we motor relatively allot. Up to Catalina which is about
78 miles from Coronado we are both into the wind and into a .5 to 1 kt
current. So motoring is the thing. The Autoprop gets WindWalker II 7.1 kts
at 2600 rpm which is our normal transit mode. In 61/2 years we have about
450 hours on the engine.

WE do not use it much for our day sailing, into and out of the slip but on
the long trips it is well used.

Cheers,

Dick Walker
C-320 (687) WindWalker II
740 Olive Ave.
Coronado, CA 92118-2136

619.435.8986-----Original Message-----
From: C320-List-bounces at catalina320.com
[mailto:C320-List-bounces at catalina320.com] On Behalf Of Peter Clancy
Sent: Thursday, March 30, 2006 4:04 PM
To: C320-List
Subject: Re: [C320-list] folding props again

Good question. I have the Gori 2-blade folder. Price is a factor and you'd
probably have a little more drag under sail with the 3-blade prop (a racing
issue). I have a 10 year old boat with only 360 hours on the engine. So, we
sail 80-90% of the time. Folks who motor more often, particularly in windy
and choppy conditions, could probably make a case for the 3-blade having a
better "bite" and possibly driving the boat better thru such conditions
although I've never had a problem with my 2-blade folder.

Peter Clancy
AROBAN C320 #222
Miami, FL
----- Original Message ----- 
From: belairlk at aim.com 
To: C320-List at catalina320.com 
Sent: Thursday, March 30, 2006 6:52 PM
Subject: Re: [C320-list] folding props again

What is the reason most of this thread prefers the Gori 2-blade instead of
the Gori 3-blade---other than price.

Len
Aqua5 #1070 

-----Original Message-----
From: Pat Moriarty 
>
To: C320-List
>
Sent: Thu, 30 Mar 2006 11:25:51 -0600
Subject: Re: [C320-list] folding props again

So I have the same combo and was thinking about the Gori 2 blade 
also. How have you liked it so far? RPM vs speed and reverse etc. Did 
you have the 3 blade fixed before?

Pat
SEXUALHEELING #130

At 11:16 AM 3/30/2006, you wrote:
>I hope I'm not violating any usage clause with this little endorsement
>but I just acquired and installed a Gori 2 blade from AB Marine in
>Newport for my 94' hull #141 with a Perkins. They beat every price I
>could find on the net and more importantly were very knowledgable and
>helpful during prop selection and sizing. The fella I dealt with was
>Geoff Prior [geoff at ab-marine.com]
>Mike LaChance
>Seychelle, #141
>
>-----Original Message-----
>From:
C320-List-bounces at catalina320.com
>[mailto:C320-List-bounces at catalina320.com] On Behalf Of Scott Thompson
>Sent: Thursday, March 30, 2006 11:50 AM
>To: C320-List
>Subject: [C320-list] folding props again
>
>Sorry to beat a dead horse, but I can't seem to find the answers in the
>older threads on this. Surprise is 1999 wing keel model, hull 653. She
>has the Yanmar 3GM30F, continuous HP rating 24.1HP at 3400 RPM. Her
>gearbox has 2.21:1 reduction in forward gear.
>
>For cost reasons and to get minimal drag I'm only looking at the Gori
>and Martec 2 blade folders. What pitch and diameter of these props
>would be recommended for my boat? Am I correct that the shaft is 1
>inch, standard US taper?
>
>Who has the best deals on these props? Any reason to prefer Gori to
>Martec or vice versa? I've read good things about both.
>
>
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