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This is the place to discuss general issues related to the U-boat war or the war at sea in WWII. 
Re: Type IX U-boat torpedo storage and loading
Posted by: Ken Dunn ()
Date: December 11, 2008 01:45AM

Hi Alex,

The procedure for loading torpedoes into a U-boat was pretty much the same for the Type IX and the Type VII.

The torpedo would be delivered to the U-boat via a crane on the dock as in the following photo:

In the above photo you can see the open hatch to the forward torpedo room (forward torpedo loading hatch) with a cradle already in place at an angle to accept the torpedo. The torpedo (without its detonator installed) is then manhandled into position on the cradle and a cable attached to the U-boat’s portable winch is attached to the back end of the torpedo. In the following photo you can see the cable being attached. The man attaching the cable from the U-boat’s winch in the photo is actually standing on the winch which in turn is on a small stool on the deck.

Next the cable from the portable winch is strung over a pulley at the conning tower and the torpedo is lowered into the boat by use of the pulley system. The next photo illustrates the concept but the torpedo in that photo is actually being inserted into one of the above deck canisters, not being loaded into the boat. For photos to appear in a post here they have to already be on the Internet and I needed one dealing with loading and unloading one of the deck canisters so I will just use the same photo for both purposes here.

I am not certain exactly how the torpedo was manhandled into position once it was inside the boat but there was equipment in there including a pulley system to properly position them and load them into the torpedo tubes if that is where hey were going.

Now you can see that the procedure was pretty much the same for loading a torpedo into the boat or loading it into one of the deck canisters. However note that the deck canisters are pivoted so that they lay flat after the torpedo is loaded into them. In the above photo you can see that the canister has been rotated at an angle like the cradle used to load a torpedo into the boat. The device at the end of it controls the angle. In this photo you can see the cradle is positioned horizontally and the winch from the dock simply laid the torpedo on it.

As I mentioned, once the torpedo was inside the canister, the pressure proof canister was closed and rotated until it was horizontal. The deck covering was then replace and the procedure was complete.

Now comes the hard part – getting a torpedo out of one of the above deck canisters and down inside the boat at sea. That was quite a difficult job and could take a couple of hours for just one torpedo.

These torpedoes were 7 meters long (23 ft. 7 in.), 21 inches in diameter, and weighed between 3,300 and 3,600 pounds including the approximately 640 pounds of high explosive in their warheads and were extremely difficult to manhandle, especially once they were inside the extremely cramped confines of the boat.

First the boat had to find calm seas in an area where it was safe to be on the surface for that long. Just finding calm enough water in the North Atlantic could be quite difficult and as the war progressed finding someplace safe from attack for long enough to do it also became extremely difficult. Once the torpedo was positioned in the open torpedo loading hatch the boat couldn’t dive and that left it extremely vulnerable to attack, especially from the air.

Step one was to rotate the canister to the proper angle and open it. Then the portable winch had to be attached and the cables for the pulley system secured. Next torpedo had to be winched out of its container and onto a cradle that could then be positioned in front of the torpedo loading hatch. Lastly the torpedo had to be lowered into the boat and stowed away just as they were when they were loaded directly into the boat back at base. Note that U-boats generally dived in order to reload the torpedo tubes as the motion of the boat on the surface at sea made it too dangerous to try to do it there, especially after the detonator had been installed.

I have left some of the steps out because I don’t know what they were. I have never seen a step by step procedure for doing all of this but I have seen photos of the process at various stages and read descriptions of various parts of the process. For example the Type IX has some small rails (like railroad rails) along its sides for a dolly that carried the torpedoes over to the canisters and back toward the torpedo loading hatches but I have never found a detailed explanation of how they were used. I have seen photos of torpedoes sitting on the dolly though so I know what they were used for. You can see the rails here:

The process of taking on torpedoes from a supply ship at sea was basically the same as taking them on from the dock back at base.

The process of transferring them from one U-boat to another at sea was a bit different though. They would generally be pulled from their topside canisters in the standard manner and then lowered over the side into the water with the pulley system. They would have life preservers wrapped around them to help them float. They would then be floated across while being pulled by a rope or be assisted by men in a rubber raft etc. to the receiving boat which would be waiting with its decks awash. The torpedo would then be floated over the deck (probably onto the dolly if it was a Type IX but this is just a guess) and the receiving boat would surface with the torpedo on its deck. From there it had to be manhandled with the pulley system to finish the process. This procedure also required calm seas and a safe place to do it and it took a considerable amount of time. Additionally I expect the Milchkuhs had special provisions for getting the torpedoes over the side and across to the receiving boat but I am not sure.

As the war progressed the topside canisters were simply done away with. There wasn’t a safe place to take the torpedoes inside the boat at sea and the empty containers frequently cracked and filled with water during depth charge attacks. When the latter happened the boat would suddenly go into an uncontrolled dive and this accounted for a number of documented near fatal incidents and probably for some fatalities as well.

The Type XXI U-boats did have some sort of automated torpedo handling system at least for reloading the tubes at sea but I don’t know if it had a better way to initially load them into the boat.


Ken Dunn

Options: ReplyQuote

Subject Written By Posted
Type IX U-boat torpedo storage and loading Alex 12/09/2008 01:22PM
Re: Type IX U-boat torpedo storage and loading ROBERT M. 12/10/2008 06:08AM
Re: Type IX U-boat torpedo storage and loading Alex 12/10/2008 10:57AM
Re: Type IX U-boat torpedo storage and loading Ken Dunn 12/10/2008 02:56PM
Re: Type IX U-boat torpedo storage and loading Ken Dunn 12/11/2008 01:45AM
Re: Type IX U-boat torpedo storage and loading ROBERT M. 12/11/2008 08:14AM
Re: Type IX U-boat torpedo storage and loading Seawolf 07/28/2010 07:20PM
Re: Type IX U-boat torpedo storage and loading Scott Sorenson 12/11/2008 08:22PM
Re: Type IX U-boat torpedo storage and loading Ken Dunn 12/11/2008 09:13PM
Re: Type IX U-boat torpedo storage and loading nicoo 12/18/2008 02:22PM
Re: Type IX U-boat torpedo storage and loading LukeFF 01/20/2009 06:30AM
Re: Type IX U-boat torpedo storage and loading LukeFF 01/26/2009 05:20AM

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