U-boats external torpedo stores

[ametzeaala]

Hey there U-boat lovers!
Lately i've been reading a lot on uboat.net(amazing website i discovered recently).Also played a lot of silent hunter III.I observed that the type IX(and the type VII to some degree) was able to carry aditional external torpedoes.In the actual game to reload this external torpedoes takes a few hours in witch the crew and the submarine are very vulnerable.My question is,were actually are these torpedoes stored and how are they loaded inside the u-boat?

[Roches]

You're probably aware that submarines have an inner pressure hull, which is strong and cylindrical and meant to keep out water, and an outer hull which is meant to give the boat its hydrodynamic shape. The flat deck of a U-boat is part of the outside hull, as is much of the sail/conning tower.

U-boats that had externally stowed torpedoes simply had them stored under the deck, but outside the pressure hull. That part of the sub is out of the water when it's surfaced, of course, so the crew would remove the deck panels above the torpedoes and load the torpedoes into the torpedo rooms inside the pressure hull using essentially the same procedure they would use in port.

Loading torpedoes into a U-boat was done by the same process used on any other submarine. There were round hatches in the deck, usually angled at about 45 degrees, through which torpedoes were loaded into the sub. It's easy to identify torpedo hatches on a plan because they are angled.

Submarines that had stern tubes did not always have a second hatch. The VIIC/41 plan I looked at doesn't seem to have one. For these, the torpedoes would be loaded backwards into the forward torpedo room and carried to the aft tubes.


A G7a torpedo was 7.163 m long, 533 mm in diameter and weighed 1,538 kg (from de.wikipedia.org). That's 3,390 lbs; the American Mark 14 submarine torpedo was 1,490 kg or 3,280 lbs. Type VIIB and later had two external torpedoes and Type IX had 10 external torpedoes in 5 compartments, 3 aft and 2 forward.

This isn't the best quality, but here: http://www.youtube.com/watch?v=mDpNQCCsyTU
It's from someone's visit to the U-505 in Chicago, but it shows clips from a German film of torpedoes being loaded on a U-boat.

[ametzeaala]

Thank you very much!:)It is all clear now.The video is also great

[SnakeDoc]

I would like to correct this statement:

Submarines that had stern tubes did not always have a second hatch. The VIIC/41 plan I looked at doesn't seem to have one. For these, the torpedoes would be loaded backwards into the forward torpedo room and carried to the aft tubes.

All type VII (except VIIA of course) and IX U-Boats had aft torpedo loading hatch. In case of VIIC/41 it was located in the forward part of the electric motor room (which was connected with aft torpedo room). You can clearly see it on this drawing:
http://uboatarchive.net/U-570GeneralPlanA.jpg

In the later years of war the stowing of the torpedoes in the external (upper deck) containers were abandoned because of allied supremacy in the air - U-Boats could not stay surfaced long enough to charge their batteries, not to mention about long process of loading torpedoes. Also, while loading torpedoes into the pressure hull, U-Boat was not ready to dive in case of emergency - first, the equipment on the upper deck had to be properly stowed, external containers secured, loading hatch closed and crew got inside.
Also, torpedoes in the external containers were vulnerable to depth charges explosions and were very often damaged.
And one more thing - torpedoes stowed in external containers could not be maintained and serviced properly - so there were only stowed G7a - air-driven torpedoes, which were much more resistant than electric ones.

--
Regards
Maciek

[SnakeDoc]

And few photos:
drawing the torpedo of the (forward) external container on type VIIC U-Boat:

(torpedo loading hatch visible under aft part of the torpedo)

rising the (forward) external container on type VIIC U-Boat:


--
Regards
Maciek

[Roches]

Thanks, Maciek, for the correction. Since the aft torpedo hatch is located with the exhaust machinery I overlooked it on the plans. I appreciate your clarification and your link to better plans.

Thanks also for the additional information about the operational use of these torpedoes. It's particularly interesting that only the G7a could be carried externally. That makes it more clear why the Type IX would have stopped carrying external torpedoes. (The Type VII is more obvious as it only ever had two external torpedoes.)

[tigre]

Hello to all ; a little more................

Reloading torpedoes at sea!

Source: http://www.ebay.de/itm/U-BOOT-KRIEG - DUELL IM ATLANTIK - 1942-43 - DEUTSCHE U-BOOTE - KAMPF MIT U-BOOT-KILLER-/172397470296?hash=item2823b0a258.

Cheers. Raúl M .

[tigre]

Hello to all ; a little more................

Reloading torpedoes at sea! (U 178 Type IX D2).

To reload a torpedo tube with a torpedo from one of the above-deck canisters, the submarine would have to surface in calm water. Then the torpedo would be pulled out of the compartment with winches and lowered into the forward or bow torpedo room. This process could take several hours for just one torpedo, making it an easy target for Allied aircraft.

Source: http://kreiser.unoforum.pro/?1-9-0-00000010-000-30-0
U-boat Tactics in World War II. Gordon Williamson.

Cheers. Raúl M .

[tigre]

Hello to all ; a little more................

Reloading torpedoes at sea! (U 178 Type IX D2).

Source: https://c8.alamy.com/comp/CYXFWD/a-phot ... CYXFWD.jpg

Cheers. Raúl M .

[Natter]

Reloading torpedoes at sea!
Source: http://www.ebay.de/itm/U-BOOT-KRIEG - DUELL IM ATLANTIK - 1942-43 - DEUTSCHE U-BOOTE - KAMPF MIT U-BOOT-KILLER-/172397470296?hash=item2823b0a258.

Probably not an external stored torpedo, as it's a G7e (impossible to see which variant, or wether it's an exercise torpedo).

[Natter]

Reloading torpedoes at sea! (U 178 Type IX D2).
To reload a torpedo tube with a torpedo from one of the above-deck canisters, the submarine would have to surface in calm water. Then the torpedo would be pulled out of the compartment with winches and lowered into the forward or bow torpedo room. This process could take several hours for just one torpedo, making it an easy target for Allied aircraft.
Source: http://kreiser.unoforum.pro/?1-9-0-00000010-000-30-0
U-boat Tactics in World War II. Gordon Williamson.

Seems like a very early production G7e(TI) from the tail. Could be late 1930's, ie prewar..?