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

Rod via Public-List public-list at lists.alberg30.org
Sun Jun 5 19:23:31 PDT 2016


Smaller diameter 
Narrower blades
Thicker cross section 

These all sound counterintuitive 
How can it possibly work BETTER ?
There must be snake oil here somewhere.   I must get one of those magic props  (-: 


Cheers,  Rod 

<div>-------- Original message --------</div><div>From: Gordon Laco via Public-List <public-list at lists.alberg30.org> </div><div>Date:05-06-2016  9:05 PM  (GMT-05:00) </div><div>To: charles pleisse <velocharles1 at gmail.com>, Alberg 30 Public List -- open to all <public-list at lists.alberg30.org>, public-list-request at lists.alberg30.org </div><div>Subject: Re: [Public-List] Public-List Digest, Vol 3273, Issue 2 </div><div>
</div>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
>>> 
>>> -----Original Message----- From: Gordon Laco via Public-List
>>> Sent: Sunday, June 05, 2016 11:44 AM
>>> To: George Dinwiddie ; Alberg 30 Public List -- open to all
>>> Subject: Re: [Public-List] Propellers...
>>> 
>>> Thanks,
>>> 
>>> Caroline laughed at me over the battery charger/charge state thing.
>> When I
>>> noticed it had clicked off, I assumed a malfunction so went into 'grumpy
>>> Gord' mode.... 'damned thing, what next, knew something would go wrong,
>> hate
>>> batteries, when I am going to find time to fix this, probably five things
>>> wrong, not just one...' etc etc  until I realized that the issue was that
>>> the batteries were indeed fully charged...
>>> 
>>> 
>>> On 2016-06-05, 11:11 AM, "George Dinwiddie via Public-List"
>>> <public-list at lists.alberg30.org> wrote:
>>> 
>>>> Sounds like a complete win, Gord.
>>>> 
>>>> On 6/5/16 10:42 AM, Gordon Laco via Public-List wrote:
>>>>> Hello friends,
>>>>> 
>>>>> I?m sorry to reintroduce this topic... But I?ve changed propellers and
>>>>> thought I?d share the experience.
>>>>> 
>>>>> Some of you may recall that I have pontificated about taking a ?don?t
>>>>> change? position with regard to the prop supplied by Whitby Boatworks
>> with
>>>>> the Atomic IV engines many of our boats have.
>>>>> 
>>>>> Well this spring I was thinking about the engine and decided to try a
>>>>> change.  Last fall?s ?Misery Trip? reached a crescendo of suffering
>> with a
>>>>> slog to windward in 40 knot winds and a sharp chop...  We were nearly
>>>>> stopped a few times, mostly by wave action, but SURPRISE trudged along
>> and I
>>>>> would say coped better than our companion?s boats which were all fin
>> keeled
>>>>> yachts fitted with diesels.    So power delivered to the water wasn?t
>> the
>>>>> issue... What I was thinking about was alternator performance and
>> cooling.
>>>>> 
>>>>> Cooling has never been an issue with our engine, particularly since I
>>>>> replaced the old water pump with the upgrade offered by Moyer.
>> However I?ve
>>>>> been keenly aware that our cruising RPM of about 1000 doesn?t really
>> spin
>>>>> things down in the engine compartment fast enough to deliver what the
>>>>> alternator is theoretically capable of.
>>>>> 
>>>>> I liked the look of the narrowed bladed ?Campbell? props I?d seen on
>> other
>>>>> boats, and liked the idea of increasing revs while at least keeping
>> the same
>>>>> ?power in the water? situation the stock two bladed prop gave us.  So I
>>>>> ordered the Campbell which they recommend for Alberg 30?s fitted with
>> Atomic
>>>>> IV engines with 1:1 transmissions.    The vendor said he was certain
>> what
>>>>> shaft diameter and taper my boat has... But because I?m a doubter, I
>> sent
>>>>> him my old prop for reference.
>>>>> 
>>>>> In due course the new prop came back along with the old one (and he was
>>>>> right, he did already know the specs).  I couldn?t wait to try it out.
>>>>> 
>>>>> We installed the new prop as part of my condensed spring outfitting
>> (and no,
>>>>> I did not do the cap rail job I wrote about earlier.  I got busy with
>> work
>>>>> which took me away most of April and May so that?s that on that job for
>>>>> now).  Eagle eyed Rod saw the shiny new thing and commented ?I thought
>> you
>>>>> said...?     Well I know what I said, but what the heck...
>>>>> 
>>>>> We got SURPRISE into the water and after securing the rig, started up
>> and
>>>>> started the two hour trip back to our sailing club.  First thing I
>> noticed
>>>>> was that I seemed to have a lot more power in reverse than before.  The
>>>>> second thing was that prop walk seemed to have dissappeared... Amazing.
>>>>> 
>>>>> The only negative comment I?d read about these props on line referred
>> to a
>>>>> supposed loss of maneuvring power... But I was able to do the usual
>> spin
>>>>> within her length that SURPRISE normally does.    Motoring out of
>>>>> Dutchman?s Cove Marina, I found that our speed at idle was lower, and
>> that?s
>>>>> a good thing of course not unexpected because of the finer pitch.
>> Once out
>>>>> past the breakwater, we opened the throttle and both Caroline and I
>> were
>>>>> amazed.  Boat speed climbed to 6.6 knots as usual for full throttle,
>> but
>>>>> there was no roar and vibration from the engine.  I won?t say it was as
>>>>> quiet as electric, but the change from how things were was startling
>> and
>>>>> dramatic.   We were so quiet at full speed I mistrusted the knotmeter
>> and
>>>>> fired up the GPS, but it confirmed the speed.  Amazing.
>>>>> 
>>>>> We found our old cruising speed of 5.2 at 1000rpm was now 5.2 at 1400
>> (this
>>>>> second RPM was full out open throttle with the old prop). Yes the
>> engine was
>>>>> spinning faster, but at the same throttle setting and clearly not
>> labouring
>>>>> quite so hard.   The boat was so quiet we didn?t feel like we were
>> moving,
>>>>> so we did the trip at 6+.
>>>>> 
>>>>> So the prop change is rated a total success.  But there was a surprise
>> in
>>>>> store for us.  Because I was away so much I didn?t do my usual thorough
>>>>> recharge of the batteries... We started up after launch on what was
>> left in
>>>>> the batteries after the Misery Trip and months of winter lay up.   I
>> was
>>>>> glad there seemed to be enough juice to spin the engine.
>>>>> Yesterday I decided to connect up the battery charger and run it all
>> day...
>>>>> But after only moments, the charger was indicating full charge.  I
>> assumed a
>>>>> problem with the charger but after investigating, realized that the
>>>>> ?problem? was that the battery bank was indeed fully charged and the
>>>>> automatic function on the charger was sensing this and shutting off.
>>>>> 
>>>>> How could that be, I thought... Then it occurred to me that the
>> alternator
>>>>> must have run up the batteries on the trip over from the marina.  In
>> the old
>>>>> days, the alternator barely kept up with the engine?s requirements and
>> I?d
>>>>> had to charge from shore power periodically.  So it appears that
>> whatever
>>>>> was in the batteries at launch, the engine itself topped them up in
>> the 90
>>>>> minute shot over under power (wasn?t two hours because we galloped home
>>>>> faster).
>>>>> 
>>>>> Happy happy.
>>>>> 
>>>>> Gord #426 Surprise
>>> 
>>> 
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