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Re: [PSUBS-MAILIST] acrylic vs polycarbonate
Hugo - we haven't heard from you in a while. I was going through my old
flagged posts and realised I hadn't responded to your reply.
Thanks for the heads-up regarding acrylic and polycarbonate. That was an
extensive quote and I appreciate the effort.
Phil N. responded much the same way regarding characteristics of one over
the other. Plexi has very predictable properties with easily reproducible
manufacturing characteristics - and is relatively cheap. I'll be going with
polycarbonate for collision purposes, nothing more. As my boat will be
ambient that's all I need. No worrisome flow under pressure, nada.
Cheers,
Rick Lucertini
Vancouver
----- Original Message -----
From: "Hugo Marrero" <HMarrero@hboi.edu>
To: <personal_submersibles@psubs.org>
Sent: Friday, January 27, 2006 7:10 AM
Subject: RE: [PSUBS-MAILIST] acrylic vs polycarbonate
> Hi Rick,
>
> Acrylic (Polymethyl Methacylate) has been studied very thouroughly by the
> Navy and many other manufacturers. There is plenty of data available on
> Acrylyc applications for underwater vehicles which is extremely reliable.
I
> assume that there is no such data for Polycarbonate yet.
>
> According to the Handbook of Acrylics fro Submersibles, Hyperbaric
Chambers
> and Aquaria by Jerry D. Stachiw (Published by the Marine Technology
Society)
> and I quote:
>
> "There are six attributes and acceptable material must have, ranked in
order
> of importance,
> They are:
>
> 1. Reproducibility of the material's response to identical load
> conditions.
>
> 2. Predicatability of the material's response to different loading
> conditions.
>
> 3. Availability of test criteria for establishing and maintaining
> quality assurance and control procedures during fabrication.
>
> 4. Accesibility to proven design criteria for the particular material.
>
> 5. Availability of fabrication technology capable of producing
> large-scale spherical shells and shell sectors free of residual tensile
> stresses with the same physical properties as small-scale models.
>
> 6. Low fabrication costs."
>
> Hugo
>
>
> -----Original Message-----
> From: Rick and Marcia [mailto:empiricus@telus.net]
> Sent: Friday, January 27, 2006 5:20 AM
> To: personal_submersibles@psubs.org
> Subject: Re: [PSUBS-MAILIST] acrylic vs polycarbonate
>
>
> I was given a demonstration today of how acrylic (Plexiglas) fails
compared
> to polycarbonate (Lexan). It fails suddenly and catastrophically.
>
> Is there any reason not to use polycarbonate instead? Much more
expensive,
> but, according to the staff member of the plastics company who did the
demo,
> it's about 100 times stronger than acrylic and much more flexible. Other
> than not being as scratch resistant, is there any other technical reason
not
> to use poly?
>
> Rick L
> Vancouver, Canada
>
>
>
>
> ----- Original Message -----
> From: Emile D.L. van <mailto:2stroke@hetnet.nl> Essen
> To: personal_submersibles@psubs.org
<mailto:personal_submersibles@psubs.org>
>
> Sent: Thursday, January 26, 2006 12:41 PM
> Subject: RE: [PSUBS-MAILIST] Electric PSUB
>
> Michael,
>
> You made a good start with R/Csubs and reading. I shall give some awnsers
an
> commets to your questions.
> At the list is steel the material of choise for reliability and ageing
reson
>
>
>
> 1 man
> 60m operating depth
> 100m crush depth MAX (where I will run it (fresh water) won't be deeper
than
> that)
> [Emile D.L.van Essen] for these depths a safety factor of 2+ is common
> 1 ATM
> Fast
> [Emile D.L.van Essen] Why?
> Electric
> Cheap as possible
> 'Trailerable'
> No compressed air/CO2 absorbants
> [Emile D.L.van Essen] Ballast control should be done with compressed air.
A
> life support system is easyer and cheaper than yoiu think.
> Inside I want a seat, can't be doing with lying on my front.
> Ideally 1 man operation for in/out the water - (Think that's all)
>
>
> It needs to be as cheap as possible, however obviously I don't want to
> endanger my life. So I was thinking about CCTV cameras on the outside in
> pressure housing, with a array of monitors on the inside. Any thoughts?
> Things I thought about : Increased temperature and battery draw. This
would
> however, allow me to bypass the acrylic dome aspect.
> [Emile D.L.van Essen] I can help you with a dome (580 mm O.D. @ 30 mm
> thick) The view is worth it!
>
>
> Propulsion. I have a 2HP (36V) electric motor left over from another
> project, now would this be enough to propel me through the water at a
> reasonable speed? Not sure if you call it dynamic diving (use of
hydroplanes
> to dive) but that is what I was thinking and so will need some speed.
> [Emile D.L.van Essen] You can make a R/C sub slightly buoyant and you can
> dibe dynamic. A psub need freeboard . Ballast tanks should have 20-30 %
> boats volume; that dont dive with 2 HP.
>
> The other thing that I always try to aim for when I made subs in the past,
> was to make battery power the only limiting factor. So things like CO2
> absorbant/air scrubbers need to be 'bypassed'. I was thinking about
changing
> the air every 10? minutes so as to eliminate this problem (open hatch,
> nothing fancy). Anyone see a problem with this?[Emile D.L.van Essen] As
> said, a LSS is not so difficult but a internal space of 500 liter gives a
> safe dive time of 1/2 hour. You can use dive gear for emergency.
>
>
> Groet, Emile
> www.airesearch.nl <http://www.airesearch.nl>
>
>
>
>
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