SUBSIM Radio Room Forums - View Single Post - Magnetic Anomaly Detection

Wizz · 09-15-16, 04:06 AM

Hi all!

Long time lurker who posts rarely (be gentle). I wanted to start this after doing some due diligence regarding my searches for an existing thread - I have to say 10 good minutes of searching convinced me of the justification for a dedicated MAD IJN ASW thread (please feel free to correct me if required). So, with those disclaimers out of the way...

I've read something quite fascinating!

Having recently received and perused David Owen's 'Ant-Submarine Warfare: An Illustrated History' (Naval Institute Press, Annapolis, 1997) (highly recommended though a definite bias towards the more technical Atlantic theatre) I found a curious entry regarding the IJN's ASW Magnetic Anomaly Detection (MAD) capability I was hoping my learned colleagues here would be able to provide more information regarding both the simulated (stock, TMO, FOTR etc) and real world aspects of this capability.

An excerpt from page 188-189:

[START]
'On 14 November [1944], USS Halibut was subjected to an even more frightening experience, not least because of its unusual nature. Part of a wolf pack operating against Japanese convoys, the boat was at periscope depth when, just after launching torpedoes against a freighter, the crew heard a loud, high-pitched buzzing sound noise circling around them four times before a heavy explosion close on their port side. There was none of the usual noises of depth charges dropping prior to the explosion, and the submarine dived to more than 400 feet, accompanied by the noise of more explosions and considerable internal damage. The skipper reported a strange and inexplicable greenish glow in the control room, which accorded with descriptions from other submarine commanders, but no one could account for what this could have been.

Finally, Halibut was able to surface and make her way back to base, to find similar damage to the pressure hull, which led to this boat also being declared a total loss. Only when the skipper in one of the other boats made his report did it reveal what had attacked them. Large flying boats had been seen through the periscope circling backwards and forwards over Halibut's position, and it was clear that they had been using Jikitanchiki, [Wizz: 磁気探知機 - literally magnetic atmosphere look and find mechanism] the Japanese MAD system that, in this case at least, made possible and accurate and crippling attack.

This was one of the few areas where Japan had developed new technology well up to allied standards. It was a semi-automated system in which the pilot of the controlling aircraft was alerted by a lamp lighting up on the instrument panel, and a slick of aluminium powder was dropped into the sea as a preliminary marker. The pilot maintained his course until the aircraft passed out of the zone of magnetic disturbance, whereupon another slick was dropped automatically. He then had to turn and fly a course at right angles to the line joining the first two slicks and crossing it halfway between them. Once again the apparatus would release markers automatically as the aircraft flew in and out of the zone of magnetic disturbance, and an attack could be delivered on the basis that the submarine was in the centre of the pattern formed by the first, second and fourth slicks, but aimed according to a table that took into account how long the dropping of the markers had taken. Then the aircraft could attack with its own bombs or depth charges, or direct surface escorts to the markers showing the target's position, as was believed to be the case with Halibut.

So sensitive was the equipment eventually made, that boats could be located down to 400 feet below the surface and even, with a skilled pilot flying forty feet above the sea, down to a depth of 800 feet, well below the crush depth of US submarines. This formidable weapon might have achieved much more, but by the time of its introduction, aircraft and aircrew capable of operating it were in such short supply that it made little difference'.
[FINISH]

Additional information from www.subsowespac.org
http://www.subsowespac.org/the-patro...detector.shtml

USS Halibut post IJN MAD attack damage report
http://ibiblio.org/hyperwar/USN/WarD...1-12AUG45.html

Generic MAD information from YouTube

I'm curious as to how this is modelled in the game (TMO, FOTR, other etc - I note it's always mentioned by hard working modders) and any personal anecdotes of players encountering this. I sincerely found this interesting noting the otherwise lacklustre (comparatively) ASW campaign wrought by the IJN, and couldn't think of a better community to share this with.

Happy hunting to all

09-15-16, 04:06 AM	#1
Wizz Watch Join Date: Mar 2010 Posts: 21 Downloads: 35 Uploads: 0	Magnetic Anomaly Detection - IJN ASW Hi all! Long time lurker who posts rarely (be gentle). I wanted to start this after doing some due diligence regarding my searches for an existing thread - I have to say 10 good minutes of searching convinced me of the justification for a dedicated MAD IJN ASW thread (please feel free to correct me if required). So, with those disclaimers out of the way... I've read something quite fascinating! Having recently received and perused David Owen's 'Ant-Submarine Warfare: An Illustrated History' (Naval Institute Press, Annapolis, 1997) (highly recommended though a definite bias towards the more technical Atlantic theatre) I found a curious entry regarding the IJN's ASW Magnetic Anomaly Detection (MAD) capability I was hoping my learned colleagues here would be able to provide more information regarding both the simulated (stock, TMO, FOTR etc) and real world aspects of this capability. An excerpt from page 188-189: [START] 'On 14 November [1944], USS Halibut was subjected to an even more frightening experience, not least because of its unusual nature. Part of a wolf pack operating against Japanese convoys, the boat was at periscope depth when, just after launching torpedoes against a freighter, the crew heard a loud, high-pitched buzzing sound noise circling around them four times before a heavy explosion close on their port side. There was none of the usual noises of depth charges dropping prior to the explosion, and the submarine dived to more than 400 feet, accompanied by the noise of more explosions and considerable internal damage. The skipper reported a strange and inexplicable greenish glow in the control room, which accorded with descriptions from other submarine commanders, but no one could account for what this could have been. Finally, Halibut was able to surface and make her way back to base, to find similar damage to the pressure hull, which led to this boat also being declared a total loss. Only when the skipper in one of the other boats made his report did it reveal what had attacked them. Large flying boats had been seen through the periscope circling backwards and forwards over Halibut's position, and it was clear that they had been using Jikitanchiki, [Wizz: 磁気探知機 - literally magnetic atmosphere look and find mechanism] the Japanese MAD system that, in this case at least, made possible and accurate and crippling attack. This was one of the few areas where Japan had developed new technology well up to allied standards. It was a semi-automated system in which the pilot of the controlling aircraft was alerted by a lamp lighting up on the instrument panel, and a slick of aluminium powder was dropped into the sea as a preliminary marker. The pilot maintained his course until the aircraft passed out of the zone of magnetic disturbance, whereupon another slick was dropped automatically. He then had to turn and fly a course at right angles to the line joining the first two slicks and crossing it halfway between them. Once again the apparatus would release markers automatically as the aircraft flew in and out of the zone of magnetic disturbance, and an attack could be delivered on the basis that the submarine was in the centre of the pattern formed by the first, second and fourth slicks, but aimed according to a table that took into account how long the dropping of the markers had taken. Then the aircraft could attack with its own bombs or depth charges, or direct surface escorts to the markers showing the target's position, as was believed to be the case with Halibut. So sensitive was the equipment eventually made, that boats could be located down to 400 feet below the surface and even, with a skilled pilot flying forty feet above the sea, down to a depth of 800 feet, well below the crush depth of US submarines. This formidable weapon might have achieved much more, but by the time of its introduction, aircraft and aircrew capable of operating it were in such short supply that it made little difference'. [FINISH] Additional information from www.subsowespac.org http://www.subsowespac.org/the-patro...detector.shtml USS Halibut post IJN MAD attack damage report http://ibiblio.org/hyperwar/USN/WarD...1-12AUG45.html Generic MAD information from YouTube I'm curious as to how this is modelled in the game (TMO, FOTR, other etc - I note it's always mentioned by hard working modders) and any personal anecdotes of players encountering this. I sincerely found this interesting noting the otherwise lacklustre (comparatively) ASW campaign wrought by the IJN, and couldn't think of a better community to share this with. Happy hunting to all Last edited by Wizz; 09-15-16 at 04:11 AM. Reason: grammar of course :)