[Public-List] propeller choice

Mon Feb 2 11:54:54 PST 2015

Farron, at Beta Marine, has recommended a 12 x 9 three-blade prop. He is basing this specifically on his experience with Betas in A30s. Based on this, and  all the good advice received from all of you, I intend to order the 12 x 9 (Michigan Wheel, "M" series, Sailor).
regards, JayRevolution, A30 #526
      From: Gordon Laco via Public-List <public-list at lists.alberg30.org>
 To: Bill Woodford <williamwoodford at charleswoodford.com>; Alberg 30 Public List -- open to all <public-list at lists.alberg30.org> 
 Sent: Monday, February 2, 2015 2:44 PM
 Subject: Re: [Public-List] propeller choice

I guess the reduction gearing in the Yanmar is preventing the prop from
hitting high enough RPM in the water....  I think you can have up to 2" more
pitch added to your existing prop.  It's not expensive but may resolve your
issue.

As someone else wrote, there's software available, there's also the chapter
on props in Skene's Elements of Yacht Design.  There's a graph in that book
that's very informative and practical.

Gord #426 Surprise

On 02/02/15 2:29 PM, "Bill Woodford via Public-List"
<public-list at lists.alberg30.org> wrote:

> I recently re-powered my GrayMarine with a Yanmar 2GM20f.  I installed a
> three blade 12x14 "Chesapeake 3" prop.  I am NOT satisfied with this prop.
> The boat does not seem to move well at all unless I am really pushing the
> RPM's.
> 
> On my old Graymarine, I had a three blade 12x10 that moved the boat nicely
> with little effort from the engine.
> 
> No problems with cavitation from either prop.
> 
> 
> Best of luck,
> 
> Woody
> US11
> 
> 
> 
> On Mon, Feb 2, 2015 at 2:02 PM, Dwayne Back via Public-List <
> public-list at lists.alberg30.org> wrote:
> 
>> Jay,  I can move at hull speed at around 3/4 open throttle if I remember
>> correctly.  Most of the propeller shops have software they can input
>> specifics into and you can get some pretty good info, Stanley at Beta is
>> very knowledgeable as well..  I do not deal with large wave or currents on
>> Lake St. Clair so the engine and propeller seem sufficient.  With either
>> heavy currents or waves you may actually want the 20hp Beta, not sure what
>> others have experienced.
>> Dwayne
>> 
>>      On Monday, February 2, 2015 1:53 PM, Bill Wallace <
>> wayfarer3134 at yahoo.com> wrote:
>> 
>> 
>>  The 13 MIGHT fit - I would check your actual clearance, as the larger
>> props perform better, although they do slow down sailing a bit more.  I'm
>> currently running a variprop 13x12 on a Yanmar 2gm20f at 2.2 ratio, and
>> plan on adjusting it down to 13x11 for this coming summer.  I notice the
>> feathering when sailing on light air days.  The variprop is REALLY tight
>> length wise, but otherwise fits quite nicely (I had to trim part of the
>> rudder to make a bigger opening so it wouldn't hit when feathered - but no
>> loss of turning performance, actually I think the boat handles a bit better
>> after the change).
>> Bill.
>> 
>>      On Monday, February 2, 2015 1:42 PM, Dwayne Back via Public-List <
>> public-list at lists.alberg30.org> wrote:
>> 
>> 
>>  I have a Beta 16 with a 12 x 9 three blade propeller.  Ideally (according
>> to beta) you would use a 13 x 8 propeller but the Albergs do not have room
>> for the 13 blade.  I have no real complaints.  Purchased mine from Michigan
>> Wheel.
>> DwayneOrion #94
>> 
>>    On Monday, February 2, 2015 1:20 PM, Jay Davenport via Public-List <
>> public-list at lists.alberg30.org> wrote:
>> 
>> 
>>  I am installing a Beta 16 diesel in my Alberg 30. It will run at 3600
>> rpm, with a 2:1 reduction ratio.
>> The old Atomic 4 engine spun a 10 x 6 three-bladed prop. I made hull speed
>> at about 2200 rpm direct.
>> I would appreciate any advice (preferably from experience) on what 3-blade
>> prop size would work best with the Beta. I am considering a 11 x 9. Part of
>> my concern is getting the most effective push from the prop, while avoiding
>> cavitation from excessive prop diameter.
>> Jay DavenportRevolution, A30 #526
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