maximum number of VII class U-boats?

[johnm]

Rereading about VII U-boats recently, I found that over 700 were built.

Any body got any idea as to the maximum available at any one time?? I know Doenitz reckoned he needed 300 available to win the U-boat war (100 in action, 100 returning and 100 being refitted etc) How near did he get?

[meduza]

I'm not sure if this is the maximum, but at the beggining of 1943, there were almost 400 commissioned u-boats.

[melnibonian]

Here is your answer (from http://www.uboat.net/technical/shipyards/index.html)

U-boat production:
1935 (14)
1936 (21)
1937 (1)
1938 (9)
1939 (18)
1940 (50)
1941 (199)
1942 (237)
1943 (284)
1944 (229)
1945 (91)

Total: 1153

And to put things into perspective here are the losses (again from http://www.uboat.net/fates/losses/)

1939: 57 U-boats were capable of going out to sea when the war began in September 1939. When the year ended 9 of them had been lost.

1940: 24 boats were lost in 1940. U-31 was actually sunk twice so she appears twice in that number.

1941: 35 boats were lost during 1941.

1942: The U-boat fleet lost 86 boats during this year, most of them in the latter half the year. A sign of things to come ...

1943: With the biggest convoy battles of the war and the highest number of boats at sea, stakes were high. In May 1943 the biggest loss to befall the U-boat fleet came with loss of 41 boats. Overall losses in 1943 were 242 U-boats.

1944: This year was even worse than 1943, steady losses all year brought the total up to 250 boats when the year came to and end.

1945: With the war coming to an end, overwhelming allied forced all around them, Germany lost over 120 U-boats in action in the first 5 months of the year.

Finally if you want to find out the causes for the loss of all these boats check out this page http://www.uboat.net/fates/losses/cause.htm

I hope this covers it ;) :D

[Scape]

Wow, great post!

[johnm]

Using Melnibonian's figures:
year built sunk running total
1935 14 0 14
1936 21 0 35
1937 1 0 36
1938 9 0 45
1939 18 0 63
1940 50 23 90
1941 199 35 254
1942 237 86 405
1943 284 242 447
1944 229 250 426
1945 91 120 397

Meduza underestimated 1943 as almost 400 should be 447.

So they did make the 300 available but by 1942, it was too late.

At least we know. Thanks to you all.

[meduza]

Meduza underestimated 1943 as almost 400 should be 447.
Even if a boat is constructed, it doesn't necessarily mean that it's commissioned and available for operational use. :cool:

[Sailor Steve]

Number constructed vs number lost in a year doesn't really tell the story.

According to this source, in 1940 there were rarely more than 10 boats at sea at any one time.
http://books.google.com/books?id=tdYkMPfUSUAC&pg=PA238&lpg=PA238&dq=number+of+u-boats+at+sea+by+month&source=web&ots=SzHgS-7PCU&sig=C73j5sfGVrOaBYtRsQnmjNjPpO0&hl=en&sa=X&oi=book_result&resnum=7&ct=result

I'll try to get to the library and look in the book that gives the monthly totals of boats at sea. I don't recall the title right now.

[Stingray67]

If you are interested you can look in David Syrett's "Battle of the Atlantic and Signals Intelligence: U-boat Situation and Trends, 1941-1945.

It does not detail type VIIs specifically. If memory serves it does not differentiate between any types of uboats.
What it does do is present the weekly reports from the Submarine Tracking Room including the Admiralty assesment of how many submarines that were currently deployed at sea and to what areas. True, they are only assessments but they are generally considered to be fairly accurate.

In my opinion they are fantastic dokuments with a lot of interesting information.

There usually are copies for sale at abebooks.co.uk for less than 20 GBP in case it interests you.
Should be accessible via a good library as well.