[PSUBS-MAILIST] Re: In my search for a simple, cheap pressurehull ...

["Michael B. Holt" <mholt@richmond.edu>]

Phil Nuytten wrote:
> 
> Hi, Guys:
>         Got back from the Antibes/Juan-les-Pins underwater Film festival
> about an hour ago (2 hours to London and 10 hrs from London - Arghhhh!)
> and just went thru' about a swillion E's . . . (G) . . .

Welcome back. Phil.

> Vance mentioned
> that we built an E glass version of the DeepWorker : This is a prototype to
> be smooshed in the test chamber. It is straight hand-laid glass with some
> critical areas stiffened with 3" aluminum tubing 'hoops'.

Pretty much the same thing Dermott suggested.  

> The idea is to
> make a near identical copy of the DeepWorker - same functionality, etc.,
> but shallower version and very low cost ( relative to DW) and possibly also
> available in kit form. 

Kit form?  That's going to be exciting.  

>   The problem for Certifying agencies is the variation
> in hand-lay up, hull to hull. Serial certification is, therefore, pretty
> much out of the question. We propose to overcome the inconsistency
> objection by putting an overly generous safety factor on crush depth  to
> rated depth, and a high pressure test ratio. We would then plan to
> individually test each hull in the pressure chamber. We can do all sorts of
> neat stuff with some of the newer  composites but that will defeat the
> concept of very basic, very simple, very cheap.

How much extra safety factor?  Just how predictable is glass
laying?  

>         Although we have the prototype hull built, it will be awhile before
> strain-gauging and full smooshification . . .simply because of priorities.

Where do you put strain gauges on glass, Phil?  It seems that one
might find different stresses on the outside and the inside at
exactly the same point, because fiberglass is of variable density.

> . . we are behind in sub deliveries (a little bit) and I absolutely MUST
> get the swimming tests done on the Exosuit, make final design changes,
> etc., so the shallow DW ( probably 2 models - 100 meters and 200 meters)
> will have to wait.

Well, go do that, support the world economy, and get back to
us when things settle out a bit.  In the meantime, I have a 
pair of tests in two classes next week ...

Thanks, Phil.


Mike