Re: [PSUBS-MAILIST] Nice Sub Bill!

[MerlinSub@t-online.de (Carsten Standfuß)]

Hi Bill - very nice sub - looks good !

I will not use a stuffing box - cost to much power 
under greater waterpressure - I use a high pressure 
ceramic seal for the 3 inch (80mm ) stainless steel main shaft inside
the sub at the end of the shaft and a oil filled pressure compensate
mainshaft hose with standard double rubber bearing on the outside . 
The ceramic seal is in the 1500 Dollar area.. the bearing in the 15
Dollar...

But for your sub and 150 feet (46 m )deep  a standard stuffing box 
should work. 

Bill - the pressure load marked on your propane tank is for inside
pressure 
not for outside. If you have a cylinder under inside pressure and he is
not perfect rounded - no problem -  higher pressure make him rounder and 
stronger until the time the steel ultimate tensile strength border is
reached 
and than "bang". Very easy to calculate for the tank supplier. Under
outside pressure the cylinder will not reach this border for the reason
that it will collapse before because of his "not perfect roundness". 
Means if it is not perfect rounded (no cylinder with a longitudinal weld 
is that...) he will be go flat and flater under pressure starting with
this un-roundness.  Maybe one of the naitive english speakers can
explain that better. 

Please, if you want - send my a drawing 
(fax at 0049 421 679 266 or as dxf file by email)
of your pressure hull around the fairwater, say plus minus some foot
including the stiffteners design and location. Hull diameter and
tickness
,cutout of the sail and the pressure part of the tower. 
I will look for an estimate operating deep which is safe..
It looks for me that it is a good idear to stop work on the sail 
himself before a calculation is done.. 
If you can curved the flat side of the sail - maybe with a hydraulic
stamp from inside - so the flat plate is slightly curced to the outside 
- will help much. 

The pressure tight volume of the sail, and the weight also looks big 
- do you have make a stability calculation ? 

Best regards - Carsten - I am back Monday 




WGif503113@aol.com schrieb:
> 
> Hello Alex
>         Thank you very much for taking the time to check out my project.
> The rings were formed out side of the pressure hull with a slightly smaller
> dia. then the hull they were then cut and inserted through the entrance hole,
> after the ring was inserted and wedged tight a small piece was inserted to
> fill the void left by the missing dia. I agree it would be stronger on edge
> but I intend to install bulkheads in two locations. I also intend to install
> a bed for the generator as well as a built in fuel tank. The area around the
> conning tower will be totally reinforced and a bridge will be formed across
> the opening between the seats. My plan is to build the sub strong enough to
> withstand twice the pressure the tank is rated for. The original test
> pressure is 325 lb.. The entire conning tower will be reinforced with one
> half inch plate. The side ballast tanks will also add strength to the hull. I
> have now turned the hull over and am in the process of adding a keel and
> rolling chocks they too will add strength to the hull. I point I am not quite
> sure of is what type of stuffing box's to use I would like to know what
> Carstan plans to use. One option beside a stuffing box, would be to use a
> high pressure spring loaded pump seal. The only problem I foresee with that,
> is the seal failing and having no way to stop the water. At least with
> packing all you have to do is tighten the gland.
> 
>                     Regards Bill