Re: [PSUBS-MAILIST] Seals again

[s_lindblom@conknet.com (Steve Lindblom)]

As so often happens on prolonged threads, I'm managed to back myself into a
position much more extreme than I actually hold. I got nothing against
pressure compensation. It's a useful, and when done right, even elegant
solution to certain problems. And I don't question that it works. It's just
that when it's done before simpler and more cost effective methods are
tried that it becomes a bit rube goldberg.

As to redundancy, we can trade analogies about brakes, parachutes and
raincoats until hell freezes over, but redundancy is neither good nor bad
in itself - redundant systems are the foundation of safety in critical
applications, but at the same time, unecessary or overly complex redundant
systems can add more risks than they cure. I think we can both agree on
that? That's why each application and each component must be rigorously
examinined to balance the benefits and the risks, which is what I've been
trying to do here, find out why the list - the vocal ones at least - seems
to so overwhelmingly prefer compensation to good seals.

The effort has already produced some results - we found that one of your
main arguements for compensation was based on a faulty understanding of the
dynamics involved.

BTW, since you are such a fan of redundancy, are you aware that your
pressure compensation system, as you have described it, does not provide
it?

As long as you are using the stock 1 ata seals, as you said you were, then
the compensation system the only thing keeping water out of the motors at
depth. If you really wanted to "protect that baby with all the best backups
you could get" you could, by upgrading your seals, have true redundancy,
and reduced task loading, for trivial cost. Which is why I find the lack of
interest in seals here so odd.


Nemo wrote:
>Unless you're talking about some esoteric principle devised by Gene Simmons,
>I take that term to mean "Keep It Simple, Stupid!"
>
>Sounds like you're saying system redundancy in submarines is not only
>unnecessary, but also more dangerous than beneficial; and everyone who's
>been using it should now do without it because people are too stupid to
>design, build, or operate anything more complex than the most rudimentary
>machines.  That is contrary to everything I've ever read about submarine
>design.
>
>Of course, you're entitled to your opinion; but I doubt you'll convince
>automobile manufacturers to do away with emergency brakes simply because
>multi-chamber master cylinders reduce the possibility of failure; or
>convince us that pressure compensation does not safely improve functionality
>and reliably in the submersible motors we propel our submarines with, when
>for years it's been proven that it does.