[Public-list] Depth vs draft

Bill Burke BurkeNH at verizon.net
Wed Aug 30 18:26:22 PDT 2006


>From the responses it seems safe to conclude that there isn't a standard 
value that was used for the depth measurement.

To clarify, depth is defined by the Coast Guard as "the vertical distance 
taken at or near amidships from a line drawn horizontally through the 
uppermost edges of the skin (outside planking or plating) at the side of the 
hull (excluding the cap rail, trunks, cabins and deckhouses, and deck caps) 
to the outboard face of the bottom skin of the hull, excluding the keel. For 
a vessel that is designed for sailing where the interface between the "keel" 
and the "bottom skin of the hull" is not clearly defined (as is the case 
with an "integral" or "faired" keel), the keel is included in the "overall 
depth".

In short, depth is measured to the shear line midships, not to the 
waterline.  It is different from draft - its a hull dimension and doesn't 
change no matter how much stuff you load aboard. The value of 5.5 ft seems 
to be about right.  I guess I'll take a tape down to the boat tomorrow and 
measure from the shear line to the waterline as a check.

Thanks,
Bill Burke
OSPREY #116



> Date: Tue, 29 Aug 2006 16:02:18 -0400
> From: Gail DeMoss <gdemoss at alberg30.org>
> Subject: Re: [Public-list] Depth measurement for documentation
> To: Alberg 30 Public List -- open to all <public-list at alberg30.org>
> Message-ID: <44F49D4A.4060504 at alberg30.org>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> The specifications for the Alberg 30 state the draft is 4'3".  Ballast,
> 3300 lbs.  Displacement, 9000 lbs.  Beam, 8'9". L.O.A., 30'3".  L.W.L,
> 21'8" and sail area, 410 sq. ft. working canvas.  All of this
> information was found in the Chesapeake Bay Alberg 30 One-Design
> Association, Inc. handbook
>
> Although, every time we have gone aground I could have sworn we were in
> at least 6 feet of water!  Do we really have that much "stuff" on the 
> boat?
>
> Gail Dinwiddie
> Calypso #543
>
>
> Fred Parker wrote:
>
>>My recent documentation states 4.6(4 and 1/2 feet). Alert #293
>>
>>-----Original Message-----
>>From: public-list-bounces at alberg30.org
>>[mailto:public-list-bounces at alberg30.org] On Behalf Of Bill Burke
>>Sent: Monday, August 28, 2006 1:49 PM
>>To: public-list at alberg30.org
>>Subject: [Public-list] Depth measurement for documentation
>>
>>For those who have US documented A30s - what is the "depth" measurement
>>you've used?  (It should be on the document).  Rather than just
>>measuring it myself and getting close, is there a standard value that
>>people have been using?
>>Thanks,
>>Bill Burke
>>OSPREY #116
>>
>>
>
>
> --  





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