WI the need and initial order for Deutschland and Bremen were bought forward by 6 months? Duetschland making its maiden voyage in December 1915 and Bremen in March 1916.
Assuming sailing 6 months earlier butterflies the Bremen being sunk on her maiden voyage, what difference could 2 merchant uboats opening trade with the US in 1916 make?
Alright, I’ll play.
I assume you mean Bremen
not being sunk on her initial voyage, correct?
For starters the ordering of two merchant submarines in April 1915 would be
highly speculative. This was a month before the Lusitania was sunk, and in the first phase of Unrestricted Submarine Warfare. On the one hand the ability of the Submarine to pass through hostile waters is being well demonstrated, but on the other the reception of the US to this form of trade is hard to predict. Additionally with a small number of u-boats in service and the desire to sink as much tonnage as possible, DOR faces the real possibility of the boats they have ordered being taken over by the German Navy. IOTL these risks were minimized with the first USW campaign being cancelled in September 1915, a month before the Deutschland’s were ordered, earning goodwill in the US and reducing the likelihood of the loss on investment.
However, assuming they are ordered 6 months ahead of schedule, the Deutschland first sails in late December 1915, arrives in the US early January, and remains there until early February. It then crosses back to Bremerhaven by late the same month. She would sail again in late April and return in early June.
IOTL her first crossing took 9 days(with an additional week waiting at Heligoland to try and throw off British patrols) but the return journey took 22, with about 59 days between returning and putting out again. She was in Baltimore for 22 days on her first trip and in New London for 21 on her second (though she was supposed to leave after 17, but a collision with a tug delayed her). It seems a total turn around of about 110 days from beginning of voyage to beginning of voyage seems about right. That just about lines up with her planned but cancelled third trip in January 1917.
So, by that schedule she would sail again in Early August and late November. That is two more trips for her in 1916 than she managed IOTL.
Bremen, assuming she does not sink, would sail in March 1916, as well as June and October. So that is another 3 successful trips over OTL.
The other 6 would be ordered in late May. From date of order Deutschland took 8 months to be ready for first voyage while Bremen took about 10 and a half. That more or less lines up with the order to commission dates of the U-151 class IOTL so I am pretty confident using the OTL commission dates and moving them back 6 months. That would mean that the first of the new boats would be available to sail in January 1917. Then 1 in Feb, 2 in March, 1 in April and 1 in May.
So, for 1916 we have only the two originals to consider. If all 7 voyages listed above were completed and each voyage carried 780 tons of cargo (as long as at least 250 tons of that is rubber that can be stored outside the pressure hull) then in 1916 that is 5,460 tons of extra material. About the size carried by one standard merchant ship of the late war. Of this at least 1,750 tons would be rubber though probably more, with the remainder most likely being a mix of Nickel, Tin, and Precious metals.
However, there are two other things to consider.
First, even if Bremen makes it through her maiden voyage that does not make the crossing safe. Her exact cause of loss is still unknown but it is fairly certain that she had torpedoes fired at her by a British sub at one point and may have been chased by a British Cruiser Squadron. To say nothing of mines and hazards. The last time I did this calculation I reduced the OTL loss rate of one loss in three voyages to one loss per six voyages due to a limited sample size. It still seems pretty reasonable to me. If we apply that here, and assume it happens at the end of the 6 and not in the middle then we can assume that Bremen will not make it home from her voyage in October. This reduces the total to 4,680 tons (at least 1500 rubber).
Secondly, the U-boat campaign began to get sharper from about June 1916 onward. This was largely due to Jutland convincing German naval leadership that the blockade could not be broken by fleet action, encouraging more vigorous use of U-boats. In November 1916 this culminated in the voyage of U-53 which sunk a number of Entente ships immediately outside of American territorial waters. This raised tensions between Germany and the US, even though Rose, the U-boat commander had been careful to try and avoid loss of life and follow cruiser rules as close as possible in a u-boat. The sharpened U-boat campaign progressively led to relations reaching such a low that the January 1917 voyage of Deutschland was cancelled. IOTL Deutschland sailed not long after U-53’s work off the US coast. ITTL it would be nearly 2 months. If the extra time is enough for DOR to decide that a further trip is not viable then the last Deutschland trip in late November could also be cancelled. Though that is not assured. If it is that drops the total still further to 3900 (1250 rubber).
On the whole I think it is wildly optimistic to say that this increased U-boat trade would be enough to change the calculus of either Germany in regards to USW or the US in their response to German U-boat activity (and eventual DOW). The amount involved is also not going to make a drastic difference to the outcome of the war. Germany did not lose due to a lack of strategic materials. It lost due to a lack of basic materials. The U-boats cannot provide those in quantity.
en.wikipedia.org
