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Topic: Tube launched torpedo MK's? |
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David Waples
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Posted on: Mar 3, 2012 - 7:30pm
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It wasn't as far back as shown on the picture above, but looking at the drawings I have of the 109 I can't see how the tube would track out enough to miss it if it were mounted out on the edge of the deck as I've seen in some photos of boats with depth charges on the bow. If it were mounted slightly back it would explain it. Nothing definitive though.
David Waples |
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Drew Cook
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Posted on: Mar 4, 2012 - 9:47am
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My take on the close-mounted depth charges on PT foredecks -- like in the photo of the 109 running at sea, confirmed by the photo on page 89 of Ballard's "Collision With History" book -- is that the torpedomen on the boats would quite obviously and certainly have made sure the fish, when launched from from the cranked-out tubes in their firing positions, cleared the depth charges.
It seems logical to me that in the incident when the 109's forward port torpedo was jolted from its tube and knocked the port depth charge through the foredeck into the crew's quarters below (when the 109 was manuvering to deliver a bilge pump to another PT in rough seas), the tubes had probably been cranked back into their non-firing, parallel-to-the-centerline positions. Otherwise, how could the 21-foot torpedo have even touched the depth charge? "Jolted from" its tube would be the same as "fired from" its tube -- the angle and length of travel would have been the same. If the fish had been jolted from its tube when the tubes were cranked out in firing position, the torpedo would have cleared the depth charge -- or so it seems to me.
As have we all, I've seen photos of the charges placed in cut-out sections of the toe rails at the very edge of the deck, at varying distances from the ends of the forward tubes, and also photos of the rail-type racks, which carry the charges much more inboard, rolling them down the rails and overboard when released.
In the particular case of the 109, the photographic evidence shows the depth charges placed at the edge of the deck, with the aft ends of the standard racks roughly even with the aft ends of the toe rails.
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David Waples
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Posted on: Mar 4, 2012 - 2:51pm
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I took the liberty of taking Al's drawing of the 109 which shows the torpedo tube in the firing position. I estimated the location of the depth charge by taking measurements of the bands and torpedo stop on the 109 photo shown earlier. By the way if you look at the photo the depth charge does appear to be well back from the decks edge.
On the following drawing you can see where the depth charge would have to be at a minimum to be clear of the torpedo firing. You can also easily see that in the stowed position a torpedo sliding out of the tube would easily hit the depth charge as I've shown it in this drawing.
Dave
David Waples |
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Will Day
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 Posted on: Mar 4, 2012 - 4:46pm
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As a side note (that I'm sure has been answered before), were the 109's tubes swung into firing postion at the time of the collision?
Will |
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Drew Cook
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Posted on: Mar 4, 2012 - 5:32pm
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Dave,
Great schematic. Based on your drawings, I have to change my opinion that the 109's depth charges were at the deck's edge and the rearmost edge of the racks as far back as the aft end of the toe rail.
I think probably the most accurate position, based on the vintage photos and your overhead-view, indicate they were where you've placed the rearmost of the two depth charges/racks in your drawing.
Will, it seems to me, in the torpedo-jolted-from-the-tube-knocking-the-depth-charge-through-the-deck incident, the tubes would have to have been in their non-firing positions. The fish would have missed the charge if the tube had been cranked out in firing position.
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Frank J Andruss Sr
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Posted on: Mar 4, 2012 - 5:46pm
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Take into consideration that the black powder charges used, sometimes were moist or could become wet. This actually caused the torpedo to leave the tube at a slower velocity, and the vanes of the torpedo in some instances could actually hit the deck, throwing the torpedo off the mark. Same was held true if the charge was not enough. Will, I would certainly think the tubes were in the firing position before the boats got on station. Can you imagine coming face to face with a target, and trying to train your tubes out in the dark of night. I know if I were a Skipper, that would be one of the first things I would have my torpedoman take care of while still light out. Looks to me from the drawing provided that the torpedo had plenty of clearance to miss the depth charge...........
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Drew Cook
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Posted on: Mar 4, 2012 - 6:07pm
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Frank,
Are we talking about the same thing, or is Will's question referring back to the ramming of the 109 by the Amagiri?
If we were talking about the collision of the Amagiri with the 109, of course the tubes would have been cranked out into their firing positions. The boats were on a combat patrol in enemy waters. The tubes would have been cranked out and locked long before arriving on station, right? From everything I've read, the crews did this before leaving their bases.
If we're talking about the incident in which the 109's port forward torpedo was jolted out of the tube, knocking the port depth charge through the foredeck, this incident happened in the morning, after the boat came off station from a patrol around the Russell Islands.
I'm speculating because of the completion of the combat patrol and the rough seas, the tubes had been cranked back into their non-firing positions, placing the tube -- and torpedo --in line with the depth charge.
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Will Day
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Posted on: Mar 4, 2012 - 10:31pm
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Yeah, I meant tube position at the time of the ramming. I would agree that common sense would dictate that the tubes be cranked outboard, it just seems to me I read somewhere that SOP was to keep them cranked inboard as much as possible because it kept the tubes/fish better protected from the sea and pounding of the hull, plus made for a better balance on the boat.
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Will Day
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Posted on: Mar 4, 2012 - 10:38pm
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I had always assumed that a torpedo "jolted loose" from the tube did not necessarily mean it was having a "hot run"; I would think the length of the fish actually ejected from the tube would tend to vary depending on the circumstances.
Will |
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