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Post by edrotondaro on Apr 27, 2017 20:26:22 GMT -6
Hi all:
I thought I would ask the experts out there about the deployment of sonar during the Second World War. Was it strictly limited to just warships that had an ASW role like Destroyers, Frigates, Corvettes, subchasers etc, or was it found on cruiser sized ships and above. I was doing some yard work the other day and was thinking about the hapless USS Indianapolis. Wold sonar have prevented her from being torpedoed? I know that the Atlanta class CLAAs had depth charge racks which implies they had to carry sonar to use them, but was this an oddity peculiar to this class or did other cruisers carry sonar as well?
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Post by oldpop2000 on Apr 27, 2017 21:04:07 GMT -6
Hi all: I thought I would ask the experts out there about the deployment of sonar during the Second World War. Was it strictly limited to just warships that had an ASW role like Destroyers, Frigates, Corvettes, subchasers etc, or was it found on cruiser sized ships and above. I was doing some yard work the other day and was thinking about the hapless USS Indianapolis. Wold sonar have prevented her from being torpedoed? I know that the Atlanta class CLAAs had depth charge racks which implies they had to carry sonar to use them, but was this an oddity peculiar to this class or did other cruisers carry sonar as well? Hi Ed: You can put SONAR on any ship, including submarines, but which ships make the most sense. Well, cost and speed probably are two deciding factors. The subs were provided with the WCA sonar equipment. It had three transducers and 1 hydrophone. For surface ships, destroyers, destroyer escorts, corvettes and frigates made the best SONAR platforms due to the fact that they were faster and frankly, expendable. Destroyers and similar vessels were fast and maneuverable but could carry the bulky SONAR equipment plus a good supply of depth charges and hedge hogs when they became available. They also had sufficient fuel to continue the hunt for a submarine for many hours. The Atlanta class of light cruisers were originally built with sound projectors and racks but the sonar was removed when they were equipped as AAA ships, the racks remained. The Indianapolis incident was a tragic mistake made by the higher authorities for putting the ship in the position that it was in. Here is 1953 Naval Manual on SONAR. maritime.org/doc/sonar/index.htm |
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Post by edrotondaro on Apr 30, 2017 17:11:03 GMT -6
Hi Dennis:
Thanks for the link!
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Post by director on May 11, 2017 23:52:03 GMT -6
One of the issues with sonar, at least in the early years, was that sound from the ship (mostly engine noise) tended to overwhelm other noises. So the only way to use it effectively was to drop down to six knots or so - barely do-able if prosecuting a submarine but unworkable if you are cruising as USS Indianapolis was. I think - but you would need to verify - that improvements during the war got usable speeds up to 12-15 knots. And post-war, towed sonar arrays (or mounting the gear in a pod off the bow) greatly improved the gear. But even in an age of nuclear submarines, going fast means not being able to hear.
At that stage of the war it was routine for ships to steam unescorted so long as they kept to a fairly high cruising speed and zig-zagged. Indianapolis had bad luck, compounded by no-one wondering why the ship was overdue.
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Post by oldpop2000 on May 12, 2017 7:36:06 GMT -6
One of the issues with sonar, at least in the early years, was that sound from the ship (mostly engine noise) tended to overwhelm other noises. So the only way to use it effectively was to drop down to six knots or so - barely do-able if prosecuting a submarine but unworkable if you are cruising as USS Indianapolis was. I think - but you would need to verify - that improvements during the war got usable speeds up to 12-15 knots. And post-war, towed sonar arrays (or mounting the gear in a pod off the bow) greatly improved the gear. But even in an age of nuclear submarines, going fast means not being able to hear. At that stage of the war it was routine for ships to steam unescorted so long as they kept to a fairly high cruising speed and zig-zagged. Indianapolis had bad luck, compounded by no-one wondering why the ship was overdue. Sonar in the case of the USS Indianapolis made no difference since she did not have sonar or depth charges and according to the experienced Japanese captain who testified, it would have made no difference, since he could easily sink a ship zig-zagging. The Indianapolis was just a series of mistakes made by the US Navy with an attempt to point the finger at one captain and hide the mistakes made. But yes, the noise from high speed screws in the war would be easy to detect by hydrophones on a submarine, but what other defense does a lone cruiser have in unfriendly waters. Good article on underwater sound detection - uboat.net/articles/id/52 |
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Post by Enderminion on May 18, 2017 15:45:49 GMT -6
somebody had to carry the bomb, bad luck for the ship that did
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Post by oldpop2000 on May 18, 2017 16:04:54 GMT -6
somebody had to carry the bomb, bad luck for the ship that did The bomb had already been delivered and the Indianapolis was ordered to sail, alone in submarine infested waters to Guam, then to the Philippines to prepare for the invasion of Japan. She should have been escorted. |
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Post by Enderminion on May 18, 2017 21:09:19 GMT -6
somebody had to carry the bomb, bad luck for the ship that did The bomb had already been delivered and the Indianapolis was ordered to sail, alone in submarine infested waters to Guam, then to the Philippines to prepare for the invasion of Japan. She should have been escorted. o |
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