[Public-List] Propellers

[Bart Knapp]

John:

I had already come the conclusion that the Alberg is not a boat suitable for
the type of trip I had last summer - needing to go too fast, too many
people, etc.  To me, it would be fine for the ICW with one or two additional
crew and with no time table to keep up with - in other words a perfect
retirement cruise.  I agree with you if speed is the goal the Alberg does
not fill the bill.  If money were not an issue, I'd put in an electric
propulsion system and be done with it. Motors, gas or diesel, are just too
loud and distracting to use more than what is minimally needed for safe
maneuvering and other safety issues.

Bart

-----Original Message-----
From: public-list-bounces at lists.alberg30.org
[mailto:public-list-bounces at lists.alberg30.org] On Behalf Of John Riley
Sent: Monday, November 14, 2011 2:13 PM
To: Alberg 30 Public List -- open to all
Subject: Re: [Public-List] Propellers

If your desire is to go 'fast' while motoring, a motor boat will be MUCH
better suited to the purpose.

An Alberg 30 is a sail boat.  Period.  It's not a motorboat, nor is it a
'motor sailer.'

EVERYTHING about the design of the hull is the way it is for sailing.

If you were getting 7.5 knots over ground (was there a FAVORABLE
current?), you were doing pretty darn good.  No prop is going to get you
better than hull speed...it's all about Load Waterline and wave making. 
She's not a planing hull, so there is no "faster."

I would like to hear other's comments on this, but I have found bottom
condition to be a BIG factor in boat speed (and low speed handling).  A
crusty bottom only hurts; how much it hurts may vary.

Plan to motor no faster than 5-6 knots through the water, and that not
efficiently.  My "efficient" motoring speed is about 4-4.5 knots through
the water.

John
#521, Gaelic Sea

Bart Knapp wrote:
> In the refit of our A30, it occurred to me that now would be as good a
time
> as any to upgrade the propeller.  This past summer I was on an Allmand 31
> with a two bladed prop and in company with an Erickson 35 and Shannon 39.
> We were on the ICW from Galveston to Corpus and initially had the wind
> directly on the bow.  The Allmand had quite a task keeping up with the
other
> two.  I know that just by size of the boat, there would be a problem, but
> with both the Erickson and Shannon throttling back, the Allmand had all it
> could do to keep within about two miles of the others - that was under
full
> sail (after the wind had shifted) and the motor running.  The owner of the
> Erickson said that by changing from a two bladed to three bladed prop, the
> Allmand would have picked another knot or so.  The Allmand was pushing to
> get 5 knots over ground with motor only and was just tipping 7 - 7.5 motor
> sailing with a favorable wind direction and about a 30-35 degree heel.
>
>  
>
> Even though the A30 is currently land locked on a lake and effectively dry
> docked because of the drought, if we get it to Galveston Bay, we will then
> be able to get out to the Gulf of Mexico and the ICW.  I am looking toward
> sailing on the bay and take an occasional trip on the ICW.  Those trips
may
> be in the company of other boats including the Erickson and Shannon, but
> some others that are close to the same size as the A30 and going on up in
> size.  Most of these cruises would be on conjunction with Sea Scout
cruises
> as was this summer's.  I came away from the cruise this summer with the
> feeling that the Alberg would not be a good boat for the type of use we
put
> boats to on the summer cruise, but it is a case of a bird in the hand - an
> A35 would be better, but..
>
>  
>
> Anyway, if I do change the prop out, what would be the size and pitch I
> would need to be looking for.  Currently it would be married up to an A4.

>
>  
>
> Any thoughts or ideas would be helpful.
>
>  
>
> Bart Knapp
>
>  
>
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>   


-- 
John S. Riley
S/V Gaelic Sea
1972 Alberg 30 #521

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