Convoy decision

[scudder]

So I was on my second patrol of the war, Oct. 1939. I came across a huge convoy, and at it's center was the HMS Rodney. I had arrived ahead of the convoy, and the seas were pretty choppy, so I was able to get in position close and perpendicular to the convoy's direction of travel. I had 4 torpedoes left, all in the forward tubes, and my choice of targets as about 1/2 to 2/3 of the convoy was within ideal range and at the right AoB at the same time. There were several smaller merchant ships, a few medium tankers, one or two large tankers, and the crown jewel massive battleship in the center. I chose to go for the gusto and fire on the Rodney. I put all 4 () torpedoes in her side, and she went down before too long.

I felt pretty good, until I realized I just let the entire convoy of materials and fuel proceed on to Britain unharmed. So what would a Kaleun do IRL? Sink the battleship so the next convoy isn't as well protected, or try to get at as much merchant tonnage as possible, even if it means letting the battleship get away scott free?

[padi]

I think he choose the Battleship because it is very prestigious to sink a great warship like a battleship or a carrier.

[HundertzehnGustav]

two for the rodney, two for two tankers...

[Jimbuna]

Go for the Rodney...a BB is simply too tempting to pass by.

[sublynx]

In this book

http://eaglescholar.georgiasouthern...._201005_MA.pdf

you'll find a description what Prien did when confronted with a task force of troop transports and a cruiser: one torpedo for each ship. At that point he didn't know that the torpedoes would likely malfunction, though. If he had anticipated failure the decision would likely have been different.

In BdU's war diary

http://www.uboatarchive.net/BDUKTB30261.htm

it reads that the U-boats taking part in the operation for supporting the invasion of Norway were not to attack "secondary targets" like merchant ships or convoys that were not part of Allied counteroperations. However there is no restriction attacking battleships.

I would think that a battleship would always have been a U-boat commander's number one target. Personally I would prefer to sink any of those darn carriers if given the choice between one and a battleship. I hate those airplanes

[Sailor Steve]

Originally Posted by sublynx

I would think that a battleship would always have been a U-boat commander's number one target.

Jürgen Östen certainly agrees.

[Marcello]

Originally Posted by scudder

I felt pretty good, until I realized I just let the entire convoy of materials and fuel proceed on to Britain unharmed. So what would a Kaleun do IRL? Sink the battleship so the next convoy isn't as well protected, or try to get at as much merchant tonnage as possible, even if it means letting the battleship get away scott free?

Battleships were almost irreplaceable, as the long construction time meant that an unit ordered during the war would not be ready before the end. There was also only a limited number of them, so the loss of even a single one could have an impact on operations. Tankers were much more numerous and easy to replace.

[Jimbuna]

Originally Posted by Marcello

Battleships were almost irreplaceable, as the long construction time meant that an unit ordered during the war would not be ready before the end. There was also only a limited number of them, so the loss of even a single one could have an impact on operations. Tankers were much more numerous and easy to replace.

I'm afraid that was not always the case.

USS Iowa.......................Laid down June 1940 and Commissioned Feb 1943

USS South Dakota...........Laid down July 1939 and Commissioned March 1942

[Marcello]

Originally Posted by Jimbuna

I'm afraid that was not always the case.

USS Iowa.......................Laid down June 1940 and Commissioned Feb 1943

USS South Dakota...........Laid down July 1939 and Commissioned March 1942

Not to be a nitpicker but for, say, Iowa you are looking at 1938-1939 for order and design, making it effectively prewar. It also took nearly half a year before it was actually committed to operations.
If you decided you needed a new battleship after the war had started to replace losses, most likely you would not get it before it was game over. That is what I was trying to say.
Yes, programs started before the war could and did yield results within useful time, but if you were starting from scratch it would not be possible to get them ready quickly enough. Typical example would be HMS Vanguard, despite being ordered in early 1941 and being designed to make use of existing components to expedite construction it was not ready before it had become irrelevant.

[Jimbuna]

Your not nitpicking at all but the USS Missouri for example wasn't ordered till June 1940 but was still launched and ready for combat by June 1944.

[Marcello]

Originally Posted by Jimbuna

Your not nitpicking at all but the USS Missouri for example wasn't ordered till June 1940 but was still launched and ready for combat by June 1944.

It was commissioned in June. Note however that like Iowa it spent a good six months afterwards training and fine tuning before being actually sent to the theater and committed to operations. By then the IJN had de facto ceased to exist as a surface opponent. Could it have been used sooner? Maybe, but I would bet there would be a lot of crossed fingers in that case.

My last contact with the convoy was while commanding U-384.

1943 January 12, grid AK0345

Time: 7:30 in the morning

Diesel reserve 30-35%

Weather: clear sky, Wind 15 m/s

Failed to position myself closer to the convoy. Was observing large convoy passing by in about 7 km away from me. Reported BDU. Speed 8 kn, Course 80. BDU responded with the request to report convoy status hourly. Was about to pursue the convoy when I spotted small merchant already far away left behind from convoy. Strugling after it in about 3 knots. Decided he was probably damaged by storm. Fired 4 torps in total. 2 missed, 1 dud, the last one had it. Sunk instantly. Decided not to follow convoy, due to low fuel. Still had 5 torps left. But I was far away from base to La Rochelle. Perhaps on the return course I will have to meet with supply u-boat not too far away, for extra diesel..