Re: Reply to: [PSUBS-MAILIST] ABS - 3/17.1.1 - Normal Ballast System

[VBra676539@aol.com]

Jeez, Hugo--we need to talk. I expect that little personal shot in front of 
your response about me being a tech instead of a pilot on the JSLs was intended 
to put me in my place. Consider it done. I was a technician on all the 
submersibles I worked on, even the ones I didn't pilot.

I surely do appreciate the breakdown you gave us. It was informative and 
should be helpful to the group at large. And, semantics aside, I think we're on 
the right track--aside from the occasional rabbit punch, that is.

For instance, I expect you figure the rollover scenario for a PC-14 class 
boat was some form of fantasy on my part. Not so, I assure you. I'd resent the 
implication that I would make this up if it wasn't so damned silly in the first 
place. In fact, the man who knows more about them than anyone, and has rebuilt 
both models and resold them, was the one who told me about it. And showed me 
the numbers. And the Perry "what-if" stuff. Of course, there was a lot of 
stuff going on during the late 60s and thru the 70s that sounds like science 
fiction today. We had fewer bean counters to deal with, so maybe we just got away 
with more than is currently possible.

As to ballast/buoyancy--you are absolutely correct, of course. And so was I. 
A variable BALLAST tank allows you to change the weight of the submarine, plus 
or minus, without changing its displacement, which alters the vehicle's 
BUOYANCY. Add ballast, lose buoyancy--subtract ballast, gain buoyancy, right? But, 
your references to ABS, et al, were on the money. It's important that we have 
a common lingo. Keep in mind, however, that the US Navy considers ballast the 
material being stored, brought aboard or discharged (from weapons to sea 
water) and buoyancy to be the state of the boat, whether submerged or not.

And air compensated means air compensated--which is what I said about the 
JSL's VBT system. It takes a lot of air--which the subs carry. That's what it 
says in MY ops manual, too. Including the fact that they have main ballast tanks 
large enough to float a Volkswagen--which also require a grunch of air, 
especially when blown at depth (which they never are but need to be able to do in 
case one personnel chamber or the other is flooded). And I seem to remember 
something about the aft T-bottle rack being added in preparation for 
recertification from 1000 feet, the original ABS cert depth, to 2000 and then deeper. 
You'll have to check with Dom on that, I don't recall. Of course, I was only a tech 
in those days, so... 

You discussed payload changes in reference to the JSLs without mentioning the 
fact that HBOI has added a whole truckload of syntactic foam to account for 
the (more or less) full-time science package mount, and that the hulls are 
larger (acrylic spheres) and thus have slightly enhanced payload capacity. In the 
days when I was a TECHNICIAN, we didn't have the luxury, and had to swap 
things around pretty routinely. I realize that this is still done, and that the 
package is tuned to its researcher, but it must be amazingly nice not to have all 
that bolt this and and unbolt that rigamarole we went through. Of  course, 
the subs are the size of Greyhound buses these days as a result, but who's 
counting? They are the hardest pushed and (I would guess) the hardest dived 
research subs on the planet, and who can argue with that kind of success? Who wants 
to?

I really like your attention to detail. It is one of the perks and demands of 
being in the biz full time, which I no longer am. And thanks for pointing 
that out. However, I was a pretty busy member of the community at one time, 
including the first operational dives PC-1204 ever did after its construction for 
us at InterSub. That was east of the Shetland Islands, and throughout the North 
Sea oil patch. And yes, I was a technician then, too. I piloted the subs full 
time, and then I drank coffee until the wee hours working on the damned 
things. I made a hundred or so dives in 1204 that year alone. And in my spare time 
I did time sheets for the crews, trip tickets and mission reports to the 
office, and played liason with the contractees.

I'm really glad to hear from someone else who knows about the 12-boats. They 
don't get much historical credit, but we did thousands of dives in them, safe 
and sound, and they always brought us home. I worked on the 18s (are you 
getting the idea that we were ALL technicians?) but never ran one. I piloted PC-8, 
12-01, 02, 04 & 05 while I worked for Intersub. They were more or less 
interchangable (except 02 which was a 12-boat with a lock-out chamber).

Mind you, I absolutely did not remember that the ballast tray had that much 
weight in it. Egads, man!!! 2400 pounds. I can't imagine why we or Perry 
thought we needed that much. That was a cool little detail. Thanks.

Best Regards,
Vance Bradley



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