[Public-List] Public-List Digest, Vol 3273, Issue 2

[John Birch via Public-List]

Agree, water doesn't change in the apparature, but compression does. Skenes 
101.

Think it's bad on a A-30, an A-37 has the same sized apparature. Thumpa, 
thumpa, thumpa
; )

Still, a two blader myself, but a Campbell 2 blade looks interesting at 12 
'' to get a better tip clearance.

Cheers

John

----- Original Message ----- 
From: "Gordon Laco via Public-List" <public-list at lists.alberg30.org>
To: <sail_505 at hotmail.com>
Cc: "Alberg 30 Public List -- open to all" <public-list at lists.alberg30.org>; 
"charles pleisse" <velocharles1 at gmail.com>; 
<public-list-request at lists.alberg30.org>
Sent: Monday, June 06, 2016 8:19 AM
Subject: Re: [Public-List] Public-List Digest, Vol 3273, Issue 2


>I don't doubt that.   In any case, we're calling the exercise a success.
>
> G
>
> On 2016-06-06, at 8:06 AM, <sail_505 at hotmail.com> wrote:
>
>> Gord,
>>
>> The quietness is probably a result of less prop-wash against the hull due 
>> to the reduced diameter. With an aperature, like the A30, the prop should 
>> be no more than 85% of the aperature...the original 13" prop was nearly 
>> all of the opening.
>>
>> Mike Lehman
>> ~~/)~/)~~
>>
>>
>>
>> On Sun, Jun 5, 2016 at 6:05 PM -0700, "Gordon Laco via Public-List" 
>> <public-list at lists.alberg30.org> wrote:
>>
>> Hello friends,
>>
>> Found it already.  The old prop, factory installed at Whitby Boatworks, 
>> is a
>> two blade 'Columbian' 13 diameter x 7 pitch.
>>
>> The new Campbell prop is 11 x 5.
>>
>> As I wrote below, the Campbell prop is very different.  The blades are 
>> thick
>> in cross section with rounded somewhat blunt leading edges, not sharp. 
>> Each
>> blade is quite a bit narrower than each of the old two blade prop's 
>> blades.
>> The aggregate result is that although there are three blades, there's 
>> only
>> something like 20% more area than the traditional two bladed prop.
>>
>> My understanding of the quietness is that there is never a time when more
>> than one third of the area of the prop is masked by the sternpost... So 
>> I'm
>> not getting that 'whomph' caused by BOTH blades being masked, all the 
>> area,
>> twice every rotation.
>>
>> I'll send a picture of the new prop if people write me off line.
>>
>> Gord Surprise 426
>>
>>
>> On 2016-06-05, 8:28 PM, "charles pleisse via Public-List"
>> <public-list at lists.alberg30.org> wrote:
>>
>> > Gord,
>> > Was your new Campbell prop a 2 or 3 blade prop?
>> > Charlie
>> > Sookie 221
>> >
>> > Jun 5, 2016 at 3:05 PM, via Public-List 
>> > <public-list at lists.alberg30.org>
>> > wrote:
>> >
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>> >> Today's Topics:
>> >>
>> >>    1. Re: Propellers... (Gordon Laco via Public-List)
>> >>
>> >>
>> >> ----------------------------------------------------------------------
>> >>
>> >> Message: 1
>> >> Date: Sun, 5 Jun 2016 14:12:52 -0400
>> >> From: Gordon Laco via Public-List <public-list at lists.alberg30.org>
>> >> To: Don Campbell <dk.campbell at xplornet.ca>
>> >> Cc: Alberg 30 Public List -- open to all
>> >>         <public-list at lists.alberg30.org>
>> >> Subject: Re: [Public-List] Propellers...
>> >> Message-ID: <7CF3D811-D6FB-4664-8C6F-F8423E87C99C at csolve.net>
>> >> Content-Type: text/plain;       charset=utf-8
>> >>
>> >> Hi Don
>> >>
>> >> It's 3x as per Campbell standard for our boats.  Pitch and diameter 
>> >> are
>> >> also as per their advertised standard made for our boats, engines and
>> >> transmission ratio
>> >>
>> >> G
>> >>
>> >> On 2016-06-05, at 2:01 PM, "Don Campbell" <dk.campbell at xplornet.ca> 
>> >> wrote:
>> >>
>> >>> The only things you have not given us is the diameter and pitch of 
>> >>> this
>> >> new machine! I am guessing a two blade because of your comment on the 
>> >> stock
>> >> blade from Whitby B.W. but not sure on that either.
>> >>> Don Campbell
>> >>>