[Alberg30] Positive Stability Range

[Gordon LACO]

on 3/5/03 10:19 AM, George Dinwiddie at gdinwiddie at alberg30.org wrote:

> Alfredo wrote:
>> Greetings,
>> 
>> Does anyone happen to know the positive stability range of the Alberg
>> 30?
> 
> Back in 1994, Jack Hornor estimated the positive stability range to a
> bit under 120 degrees.  Judging from the graph he gave out, I'd say
> about 118 degrees.
> 
>> Also, I know the total working canvas area of our boats. But, what's
>> the area of just the main?
> 
> The sailplan (http://www.alberg30.org/boat/A30sailplan.jpg) shows a
> figure of 221 sq. ft. for the main.  The fore triangle is 189 sq. ft.
> 
> - George
> 
Hello mates - 

I am surprised at a figure as low as 120... last year I was up to my hips in
a problem involving a sailing ship whose Limit of positive stability was
under 100.  In the course of working on that issue I came across material in
Machaj's "Seaworthiness - the forgotten factor" that indicates "dangerous"
yachts having numbers under 130, (yachts lost in the Fastnet of '79 are used
as examples - Grimalkin had an LPS of 125) and yachts of our type - narrow
with full keels having numbers of 160 degrees and more.   When you say 120
degrees - what are you refering to?  When I say 160, I mean that I expect
the boat to still have a righting force that will return it to an upright
position.

Gord
#426 Surprise


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