Path: utzoo!utgpu!watserv1!watmath!att!cbnews!military
From: welty@lewis.crd.ge.com (richard welty)
Newsgroups: sci.military
Subject: [Re: H202 Submarine Propulsion (was Re: Nicknames)]
Message-ID: <1990Aug15.032837.27755@cbnews.att.com>
Date: 15 Aug 90 03:28:37 GMT
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Organization: AT&T Bell Laboratories
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From: richard welty <welty@lewis.crd.ge.com>

From: henry@zoo.toronto.edu (Henry Spencer)
>  (Most people don't realize how limited the conventional subs of
>the time were; once they submerged, they could stay under for a day or
>two at most, and speed on batteries was typically *two knots*.)

a day or two under sounds about right, but most sources on,
for example, the US Fleet boats in the Pacific give best
underwater speeds of 8-10 knots.  there was (is) an inverse square
relationship between forward speed and endurance, as i recall,
and so 2 knots may be accurate *if* you want to stay down for two
days.

>  The idea
>looked good, but three things stalled it.  One was the obvious problem,
>that Germany was rapidly going down the tubes.  Another was competition
>from a rethinking of the conventional design, in favor of much higher
>battery capacity.  That improved the conventional sub so much that it
>became the standard for later versions

in fact, after the US got their hands on the late-war german
uboats, they redesigned/reconstructed the newer/less-abused of
their fleet boats along the same lines; these were called the
guppy conversions.

>advantages did not look as impressive any more.  The death knell was
>nuclear propulsion, which made all the chemically-fuelled subs look
>like toys by comparison.

many argue that the US was too quick to discard the conventional
submarine, though.  they're cheaper and they're quieter (batteries
driving electric motors make a lot less noise than reactors driving
steam turbines driving generators driving electric motors.)  the
US has retained in active service a number of older conventional
powered subs so that anti-sub forces can practice exercises and learn
about the unique problems presented by conventional powered submarines.

richard