welty@lewis.crd.ge.com (richard welty) (08/15/90)
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
military@cbnews.att.com (William B. Thacker) (08/23/90)
From: att!utzoo!henry >From: richard welty <welty@lewis.crd.ge.com> >many argue that the US was too quick to discard the conventional >submarine, though. they're cheaper and they're quieter... Although it's true that the USN abandoned conventional subs too quickly, one should be a bit cautious about such statements. Conventional subs are cheaper and quieter, yes... but they do different missions than the ones the nuclear subs are used for. A good fraction of the cost of nuclear attack subs is high-end sonar equipment for hunting hostile subs in the open ocean. Such equipment is seldom fitted to conventional subs, and on the one or two occasions when this has been done, they didn't look so cheap any more. As for quiet, yes, they're extremely quiet when sitting dead in the water or motoring along at low speed. But if you are doing something that needs long-range mobility underwater, they simply can't do it at all. They do not have the speed or endurance; for long-range work, they are surface vessels, and noisy ones at that. It is important to understand that conventional and nuclear submarines are two very different types of vessels with very different characteristics. A nuclear sub is not just a conventional sub with a more expensive propulsion system, in the same way that an aircraft carrier is not just a helicopter- equipped destroyer with a bigger flight deck. There are some jobs that the destroyer does better, but it is not a viable substitute for a carrier if you are trying to do a carrier's job. Nuclear propulsion was such a vast improvement on conventional sub propulsion -- in most ways -- that nuclear subs rapidly evolved in very different directions from conventional ones, exploiting the new propulsion to do things the conventional subs couldn't. The two types have quite different missions now. Henry Spencer at U of Toronto Zoology henry@zoo.toronto.edu utzoo!henry
ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) (08/28/90)
From: ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) >As for quiet, yes, they're extremely quiet when sitting dead in the water >or motoring along at low speed. But if you are doing something that needs >long-range mobility underwater, they simply can't do it at all. They do >not have the speed or endurance; for long-range work, they are surface >vessels, and noisy ones at that. > >It is important to understand that conventional and nuclear submarines >are two very different types of vessels with very different characteristics. >A nuclear sub is not just a conventional sub with a more expensive propulsion Very true. Look at the shape of a typical WW2 diesel sub (and even USS Nautilus, the first of the nuclear boats). Look at the bow. It looks like the bow of a suface ship, with a straight vertical line. The entire hull has an oval cross-section, with the long dimension vertical. Why so? The subs were designed to spend much of their time on the surface, and were a compromise between surface and under- water handling. Now look at a typical nuclear powered sub (from Skipjack on.. I can't remember if the Skipjack was nuclear powered, or a diesel powered test model for the new shape). The hull is cigar-shaped. The cross-section is circular instead of oval. The new hull shape emphasizes underwater performance over surface handling, as these subs spend most of their time submerged. In fact, they make awful surface ships the few times they needed to be - usually during sea rescue in storms.
ron@hpfcso.HP.COM (Ron Miller) (08/28/90)
From: ron@hpfcso.HP.COM (Ron Miller) Re: Conventional subs & such My CO called conventional subs "manned mines." An accurate description I think. They can't move far quickly but for crowded waters and restricted chokepoint areas, they're pretty effective. US naval strategy has not chokepoints that the US needs to buy equipment to defend. Our allies tend to though (UK, W.Germany) Ron Miller formerly of USS CINCINNATTI