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Hi Jay, I agree that weight and balance calculations are very useful design tools that can save a design concept, improve it, or see that you need to abandoned it. It's not required however for one to build a functional sub. But if one chooses to take that gamble, they might in the end, just have the meanist lawn ornament in there neighborhood. Brent From: bottomgun@mindspring.com To: personal_submersibles@psubs.org Subject: RE: [PSUBS-MAILIST] Restoring a Biber (or Beaver) midget submarine Date: Tue, 12 Aug 2008 12:23:58 -0400 Brent, While you can disclaim the need for a weight & balance calculation (does not have to be “professional” and is actually pretty simple…just requires a little discipline) every naval architecture and submarine design book that is worthwhile starts the design spiral. First define your requirements, next compose an initial layout sketch, then start your weight & balance calculations, and then rough stability calculations…at any point along the way the numbers do not look right, you go back to the start and refine your spiral until you have a stable design. While there are submersibles that have operated without these, there are a lot more sitting as rusting lawn ornaments…the Needlefish is an expensive example. We have an obligation as PSUBers to promote safe designs and safe design practices, any other avenue is negligent. This doesn’t mean that we can’t daydream or explore innovative ideas but we must carefully label these as unproven and/or dangerous so the neophyte doesn’t go down the wrong avenue and the experts don’t label us as cranks.
The Biber design was a proven death trap and this is why the Nazis moved on to the Seehunde design which was better but still deadly to its operators. The Seehunde was still in the experimental stage when it was deployed as a weapon and the operators recognized missions as being suicidal. New submarine service awards were developed to recognize K-verbände members who had completed only one mission…no one ever survived to receive the gold-level award. R/Jay
Respectfully, Jay K. Jeffries Andros Is., Bahamas
Talk sense to a fool and he calls you foolish. - Euripides (484 BC - 406 BC)
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Brent Hartwig
Greetings Joe, Cheers,
From: joeperkel@hotmail.com
Jens, This is Jay not Ray. J When dealing with a small submersible there are a lot of constraints to design due to the size. While it is interesting to build a historical look-a-like, we should strive to follow modern conventions for the sake of safety. Any vessel that is used for war has a greater inherent risk of disaster and small submersibles were generally considered one way missions…these risks are accepted as part of the design objectives. In our case since we are not dealing with a war vessel and start from a different set of design objectives that should place safety paramount, we will make many different design decisions than those found in the Seehunde. In other words, we would be better to start from ground zero in design of a PSUB.
Joe Perkel looked at designing replica NR-1 and Alvin look-a-likes upon a K-350 hull. He retired from this effort for other reasons but found many constraints and would have found more once he became involved with weight and balance along with stability calculations.
Thanks for the reference, found a copy that I will purchase next payday to add to my large library on submarines. R/Jay
Respectfully, Jay K. Jeffries Andros Is., Bahamas
Talk sense to a fool and he calls you foolish. - Euripides (484 BC - 406 BC)
-----Original Message-----
Ray...
Good to hear you say this... :)
Are you familiar with the book "Die Seehunde - Klein-U-Boote, Letzte deutsche Initiative im Seekrieg 1939-1945" by Klaus Mattes; Verlag E.S. Mittler & Sohn GmbH, 1995, ISBN 3-8702-0484-7, 224 pages.
The book presents a thouroughly presentation of the Seehunde design, complete with excellent documentation in the form of technical data, images, sketches, drawings, etc., etc.
In addition it has a big section covering the various operational aspects of the type, and finally it also has an interesting coverage of what the french navy used it for after the war was over (up to the mid-50s).
regards, Jens
** Jens, ** ** Thanks for the great image of Biber, I have Lakowski's book someplace and ** will have to dig it out for review. Instead of building a Biber ** look-a-like, consideration might be given to the Seehunde as it was a more ** stable vessel (relatively). ** ** R/Jay
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