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Re: [PSUBS-MAILIST] OSS Endcaps (Pressure hull)
Phil, Carsten,
In the drawing i made (
http://www.prismnet.com/~moki/20030126.073208/doubleXendXcapX.jpg ) i did
not use 2 "Klöpperbodens" but 2 "Korfboogbodens". There major radius is 0.8D
and there minor radius is 0.154D. In the US there are endcaps simmilar to
them called semi-elliptical dishes.(
http://www.bakertankhead.com/products.htm ). So probably Phil is right when
we talk about these semi-elliptical dishes.
About a year ago someone wrote that the endcaps of the K-subs are thicker
than the cilindrical section. I think Mr. Kittredge probably designed it
that way because of the (big) viewport in the front. What stroke me the most
on the Markasub is the location of the viewports wright through the weld of
the endcaps. And this in a big deep diving (1000 feet) pressure hull.
I am fully aware that a sub designed as two endcaps welded together is't a
simple one concerning stresscalculations. It is "simple" to build.
Greetings,
Thijs Struijs
----- Original Message -----
From: "Carsten Standfuss" <MerlinSub@t-online.de>
To: <personal_submersibles@psubs.org>
Sent: Saturday, February 15, 2003 1:51 PM
Subject: Re: [PSUBS-MAILIST] OSS Endcaps (Pressure hull)
Hi Phil,
I put two FE pictures to
http://www.prismnet.com/~moki/subfiles
showning a "Klöpperenboden" under outside pressure.
This kind of Tank-endcap is the standard in europe
- but is clear not real elliptical.
For this kind of Endcap the formulation
"need to be thicker than the cylinderical hull between them"
is right. Should have about 10-15 % more tickness than the
cylinder.
Much better solution is that - turn the endcaps 180°..
like )=(
Tadploe has the hardtank is the center of both
endcaps as pillar pipe - a very nice solution.
best regards, Carsten
Phil Nuytten schrieb:
>
> Re: Elliptical hull shape:
> Alec - the other elliptical hulled sub you were trying to think of
> is probably the 'Markasub' - actually, there have been a handful of hulls
> in this form, over the past few decades. It is not a particularly
efficient
> shape re: weight/depth etc. The ellipse is not too terrible, but the
> cylindrical transition is a killer. Ellipses (ellipsii ?) are not designed
> to be butt-welded. An ellipse without the cylindrical transition ( the
soft
> 'corner') is a semi-sphere. They become more efficient as they become
> deeper (obviously . . . sorry to go kindergarten for those who know this
> stuff) in curvature for a given diameter. Full efficiency is reached when
> the depth of curvature is half the diameter - a hemisphere - and receedes
> again as you pass this number - half an egg.
> I noted in a previous post that some-one said something to the
> effect that the 'end-caps' need to be thicker than the cylinderical hull
> between them. If the 'end-caps' are hemis, the exact opposite is true -
and
> if they are ellipsii ( I kinda like that word!) they are still likely to
be
> thinner than the tubular hull for a given depth.
> My point?? Hmmmm . . .perhaps I don't have one.
> Phil Nuytten
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