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RE: [PSUBS-MAILIST] DSV 3 Turtle, Styrofoam Shot Glass



Brent,
 
 
   The reason for my quest for finding or using foam is this:
 
   I need a substance that has a drastic difference in medium than that of water (salt or otherwise) the reason being I need this barrier to reflect sound rather than absorb it. The piezo elements we use are actually omni-dirrectional and I need this barrier to channel the sound from a set direction into this element.
 
   If this barrier is not seen by sound, (as cork was suggested) but is simply passed thru it, this will be of little use to me. sound will be heard by hydrophones on the opposite side of a circular array farthest from the sound source.
 
   From the earlier discussion, I have chosen plastic juice cups at least for initial array testing. (Other channeling devices made from differing materials could be used in later sessions.) This I will further explain as this testing array becomes presentable and should should also generate great discussions.
 
   I should point out again that I am not all knowing about this field of passive sonar or hydrophones and welcome any suggestions or things discovered thru testing and experimentation. By combining the sum of all of our know how, we can derive at better sound reception for our use aboard these submarines. This is a road to learning that is best when shared with all.
 
                                                                                                      David Bartsch
 
                                                                                
 

From: brenthartwig@hotmail.com
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] DSV 3 Turtle, Styrofoam Shot Glass
Date: Tue, 7 Jul 2009 01:07:55 -0700



Hi David and Vance,

It's interesting that just before you guys started to talk about the styrofoam going deep, I was sizing and uploading pictures I very recently took when I got to spend a fun day with a friend of mine by the name of Joe Hurst.  The pictures I took were of a signed styrofoam cup for Joe that went down 10,000 fsw with the DSV 3 Turtle in 1987.  Joe is a composites expert, and worked extensively on the Turtle and Sea Cliff DSV's.  I've got a pile of interesting data from Joe for you guys.

http://cid-5085d10eb6afe47c.skydrive.live.com/browse.aspx/Turtle%20DSV%203%20%20Pictures

Regards,

Szybowski





To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] Re: [PSUBS-MAILIST
Date: Sat, 4 Jul 2009 10:34:45 -0400
From: vbra676539@aol.com

One other thing to do is have everyone involved sign a cup, write info on the dive (location, depth, dive number, etc). The cup will squash, and the writing will squash at exactly the same rate. It will still be neat and legible after the dive and your passengers will have a neat little souvenier of their dive. It only works partially in shallow water, but after a couple of hundred feet, you get a shot glass for the bookshelf that will not reexpand or change. I've still got a few from memorable dives. The ABS certification dive on PC-8 in Norway for instance, plus my first time over a thousand feet, over two thousand and then at nearly five thousand (Pisces VI in Canada).
Vance


-----Original Message-----
From: Juergen Guerrero Kommritz <groplias2@yahoo.com>
To: personal_submersibles@psubs.org
Sent: Sat, Jul 4, 2009 8:11 am
Subject: Re: [PSUBS-MAILIST]

Hello David and Vance
the Styrofoam cups  are allways a nice joke in deep sea expeditions,  we put then in a bag attached to the epibenthic sledge or Box corer or Multicorer and let them go down to the bottom and when the device comes again on board with the sample we also have tyni cups and are allways a nice suvenir from the expedition. Other nice joke in holydays like easter is to put some boiled eggs in a bag and send them down.  If they go to 400020m deept the presure push saltwater inside the egg so when you get it on board again with the sample you have a salted egg. :-)).  Crazy things people do after some weeks on open ocean. Well part of the scientific study of effect of pressure.
Best wishes
Jürgen

--- vbra676539@aol.com <vbra676539@aol.com> schrieb am Sa, 4.7.2009:

Von: vbra676539@aol.com <vbra676539@aol.com>
Betreff: Re: [PSUBS-MAILIST]
An: personal_submersibles@psubs.org
Datum: Samstag, 4. Juli 2009, 13:13

David,
Styrofoam is a closed cell styrene foam and will compress almost immediately. Cups will go from coffee size to shot glass size at just a couple of hundred feet. Wig stands (the head you spoke of) will be slower on the inside at shallow depths, but will distort almost immediately, just like the cups. The issue is not really about crushing the air out--it is the physical collapse of the foam chambers (the bubbles). They do on come back, once crushed.
Vance


-----Original Message-----
From: David Bartsch <dbartsch2236@hotmail.com>
To: personal_submersibles@psubs.org
Sent: Sat, Jul 4, 2009 5 :49 am
Subject: [PSUBS-MAILIST]

    I remember years ago seeing an article in a National Geographic showing Alvin in which a styrofoam head was shown after the submarine had come back up from very deep. This head was stored in an external retrieval basket and was thus subjected to the pressure of this deep dive. It was shown compared to what the head looked like prior to the dive and was quite small having most of the air within it crushed out.
    How much pressure or rather how deep must styrofoam go down to expel the air within it? If it were perhaps just cups and not thicker, would it go down to say 500 feet without being crushed smaller?
    Anyone have any idea? I was concidering using simple styrofoam as an inexpensive sonar baffling for reletively shallow operations. How far down should this be good for without changing shape upon returning topside?
 
                                                        &n bsp;                                                       David Bartsch


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