Re: [PSUBS-MAILIST] sub bouyancy

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

Its depents on your design I think.. With pipe style softtanks
pods like GEO or JARO maybe PVC is a solution. The internal stern 
compartment and the stern thruster pipes of Sgt.Peppers are 
made from PVC. Also the Thruster Engines housing. There is a special
cement (Tangit) which works pretty good. 

Make shure that the sub normal storage place is a garage or
something without to much direct sunlight - PVC get quick old
under direct sunlight. Do not clean the PVC with a chemical 
with is not useful for Polyvinylchlorid - and never dive with
the sub in swimming pools witch contains chlorined water. 

I like steel - if you hit something - for example on the surface 
during a "bad weather and back to the surport ship crane" action 
- your stainless steel or aluminium softtanks get maybe a bulge, 
- your PVC tanks maybe breaks in parts. 
    
During a refit of one of the 10 years old PVC endcaps of the 
Sgt.Peppers Thrusters - the endcap  fall down from the workdesk 
- and breaks in two parts. Maybe that was a result of the influence 
of the oil inside the housing. 
I was very surpriced and purchase a new one - smash this new endcap 
hard to a wall - again and again - no result. Conclusion - If you want
to use your sub longtime - don't use PVC.. 

A very expirence friend and Psuber told my during a visit : 
"Make your sub robust like an tractor"
Thats is what I reply to my brain before I produce anything
for the new sub. 

Sgt.Peppers was more or less like a Apollo rocket: 
100000 parts and each purchase from a company wich made 
the lowest offer... Works - but need all your attention  
and a 3 page predive checklist to make shure that everything
is  still running.. 
CSSX will be more a tractor - no checklist - turn the key
and run and dive. 

see you - Carsten

HeyCLOWNeY@aol.com schrieb:
> 
> thanks for the help carsten,  thats a seriuos sub your building,but the shop
> your using there makes my mouth water just as much as the sub your building!
> i dont have any machine shop facilitys here,,just migwelders and the usual
> home owner tools,,well mabee a tad more then the normal home owner!! ohh ya
> bye the way i saw a picture of a small sub that i remebered seeing in
> sanfransico that was using pvc pipe for its soft ballast tanks,,since they
> are always at ambiant pressure would pvc be a cost cutting soft tank or would
> it be better to acess the weight one would get from using steel?