Evening all,
Here is a very interesting item that recently popped up - a self-sinking /scuttling clock mechanism for the Type 93 (Long Lance) 24" torpedo. You may recall that the long lance in conjunction with the Type 95 (21" submarine launched version), were oxygen-enriched torpedoes and their design was inspired by the British equivalent used on the Nelson-class battleships.
The Japanese invested heavily and persisted in the development as it was their main strategy to be used against the US navy prior to WW2 - fire long range accurate torpedoes (max range 40Km) well outside of the US battleship gun range and had twice the distance range over the US torpedoes (max range 14Km). In fact it did catch the US Navy off guard as initial reports suspected the torpedo hits were from Japanese subs, not the battleships nor destroyers. There were reports that some of the torpedoes "missed" the front line of ships striking and sinking ships to the rear. Further, these torpedoes were the only weapon that gave small warships, such as destroyers, the potential to cripple or sink battleships.
Naturally the Japanese didn't want for any of these highly classified oxygen-enriched torpedoes to fall into "enemy hands" - most "active" (live) torpedoes normally incorporate some form of "self-sinking" if for example they have missed their target etc - via opening of sea-water valves causing the torpedo to become negative buoyant and sink.
This specific mechanism was used only with practice warheads and if the torpedo could not be found /recovered, then it would self-sink from an adjustable timer able to be set up to a max of 36 hrs. This was achieved by the clock piston rod being pushed against and opening a sea-water valve in the practice head.
The procedure for setting the timed device is to:
1) wind the spring of the clock part; then
2) set the time until scuttling; then [FONT=&]([/FONT][FONT=&]The timer could be set up to 36 hours)[/FONT]
3) wind the spring of the valve opening device;
4) turn the coupling shaft and fix the pressure valve lever.
5) Start the clock mechanism
As stated prior, when the set time elapses, the mechanism operates the small push rod which in turn opens a sea-water inlet valve to flood the practice head, causing the torpedo to become negative buoyant.
There is an almost identical mechanism for the Type 95.
http://www.interq.or.jp/www-user/ma...om/equipment/T95jitinsouti/T95jitinsouti.html
Further I'm not aware if any similar timers were issued for non-oxygen enriched torpedoes?
As you can observe from the attached photos, the item is in excellent condition and fully functional!!! (just require some clock oiling TLC - you can see the oiling points on the underside)
Enjoy!
Cheers
Drew
BTW - If anyone has a document showing how this clock mechanism actually was installed in the practice war head please let me know!!!
Here is a very interesting item that recently popped up - a self-sinking /scuttling clock mechanism for the Type 93 (Long Lance) 24" torpedo. You may recall that the long lance in conjunction with the Type 95 (21" submarine launched version), were oxygen-enriched torpedoes and their design was inspired by the British equivalent used on the Nelson-class battleships.
The Japanese invested heavily and persisted in the development as it was their main strategy to be used against the US navy prior to WW2 - fire long range accurate torpedoes (max range 40Km) well outside of the US battleship gun range and had twice the distance range over the US torpedoes (max range 14Km). In fact it did catch the US Navy off guard as initial reports suspected the torpedo hits were from Japanese subs, not the battleships nor destroyers. There were reports that some of the torpedoes "missed" the front line of ships striking and sinking ships to the rear. Further, these torpedoes were the only weapon that gave small warships, such as destroyers, the potential to cripple or sink battleships.
Naturally the Japanese didn't want for any of these highly classified oxygen-enriched torpedoes to fall into "enemy hands" - most "active" (live) torpedoes normally incorporate some form of "self-sinking" if for example they have missed their target etc - via opening of sea-water valves causing the torpedo to become negative buoyant and sink.
This specific mechanism was used only with practice warheads and if the torpedo could not be found /recovered, then it would self-sink from an adjustable timer able to be set up to a max of 36 hrs. This was achieved by the clock piston rod being pushed against and opening a sea-water valve in the practice head.
The procedure for setting the timed device is to:
1) wind the spring of the clock part; then
2) set the time until scuttling; then [FONT=&]([/FONT][FONT=&]The timer could be set up to 36 hours)[/FONT]
3) wind the spring of the valve opening device;
4) turn the coupling shaft and fix the pressure valve lever.
5) Start the clock mechanism
As stated prior, when the set time elapses, the mechanism operates the small push rod which in turn opens a sea-water inlet valve to flood the practice head, causing the torpedo to become negative buoyant.
There is an almost identical mechanism for the Type 95.
http://www.interq.or.jp/www-user/ma...om/equipment/T95jitinsouti/T95jitinsouti.html
Further I'm not aware if any similar timers were issued for non-oxygen enriched torpedoes?
As you can observe from the attached photos, the item is in excellent condition and fully functional!!! (just require some clock oiling TLC - you can see the oiling points on the underside)
Enjoy!
Cheers
Drew
BTW - If anyone has a document showing how this clock mechanism actually was installed in the practice war head please let me know!!!
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