Re: [PSUBS-MAILIST] OSS Pressure Hull, DoubleEndcap

["Thijs Struijs" <thijs-struijs@planet.nl>]

Warren,

I wonder why you can't edit the drawing. If you need another one in another
format just tell me. I have send the same drawing to Pierre, maybe he has
some ideas. If you realy have to rebuild the model i can make a detailed 2D
drawing witch might help you.

As for the batteries i intended to place them outside the pressure hull. To
give you an idea please have a look at this:
http://www.prismnet.com/~moki/20030319.141632/ENDXCAPSXSUBXPERSPECTIVE.jpg.

Because the vissibility in The Netherlands is very poor i am not looking for
speed. I was always attracted by subs like the Comex, PC, Deep Worker and
Johnson Sea Link subs. Subs that look like crabs with al there technical
details exposed . It is just a matter of taste. Reading al the e-mails i
know that there are a lot of fortunate psubbers living near cristal clear
water. I can imagine that they would like to "fly"over the submarine
landscape at high speed. With my pressure hull it  must be possible to
achieve this. Instead of the "shoulder tanks" you could place the main
ballast tanks behind and in front of the pressure hull as is done with the
K-subs. The rear mbt can be placed in a tail. Underneath the MBT the
batteries can be placed.

Stability is something that concerns me to. Directional stability can be
achieved easely be adding a small tail  like on a helicopter or Guppy (Busby
page 134). The sub is relatively high so the ballast can be placed at a very
low point. The problem is that the weight of an double end cap sub is
reletively high. Because of the big radius of the end caps you need a lot of
steel compared to the volume of the pressure hull. I have no doubts about
the stability under normal conditions. What concerns me is what happens
after you have dropped  your ballast. It would be very uncomfortable to
survice upside down. I think that a part of the ballast should remain under
the hull. This is something that has to be calculated in a later stage.

Both types of stability can be changed afterwards. The first one by adding a
bigger tail, the second one by adding some syntactic foam to the top and a
little ballast to the bottom of the sub.

Greatings,
Thijs

----- Original Message -----
From: "Warren Greenway" <opensourcesub@yahoo.com>
To: <personal_submersibles@psubs.org>
Sent: Tuesday, March 18, 2003 3:28 AM
Subject: [PSUBS-MAILIST] OSS Pressure Hull, DoubleEndcap


> Thijs, I finally got your hull imported. I am afraid
> that
> I can't edit the model, just view it. I will have to
> rebuild the model to run FEA on it. No biggie.
> However,
> I am looking at that hull, and it's really growing on
> me. I have gotten a professional engineering opinion
> of
> the hull design, with our application being taken into
> account; it recieved high marks. The only potential
> issue
> was stability. Any input on this? A small keel would
> be
> good, and could act as a drop weight. What about a
> short
> tail structure? I am also trying to work out how much
> battery capacity we could store inside the hull, since
> this design doesn't lend itself to external battery
> pods
> cleanly. I would like any additional ideas and/or
> input
> concerning the Thijs pressure hull. I'll post an FEA
> report when I have finished.
>
> Warren.
>
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