[C320-list] folding props again

Scott Thompson sthompson at toad.net
Mon Apr 3 10:10:34 PDT 2006 

All:  If you look way, way down near the bottom of this message you will 
see my original question, namely what size/pitch I should order for the 
Martec or Gori two-blade folders, given I have the Yanmar 3GM30F and 
2.21:1 reduction.  So far, despite all of the replies, no one has 
offered an answer.  Can no one provide this info?

Scott Thompson


Darrell wrote:
> I have the 3 blade flexifold and appreciate the extra torque when I need it. 
> I also backs the boat up with little to no walk, Darrell
> ----- Original Message ----- 
> From: "Walter burnett" <selkie2003 at yahoo.com>
> To: "C320-List" <C320-List at catalina320.com>
> Sent: Thursday, March 30, 2006 6:04 PM
> Subject: Re: [C320-list] folding props again
> 
> 
> 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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