KRIEGSMARINE / GERMAN NAVY (GERMANY / WEST GERMANY)

Ship project history: Most perfect submarines of the World War II era and one of the most revolutionary projects in shipbuilding history. The decision on designing was accepted in April, 1943 after abandoning from works over XVIII series with hydrogen peroxide turbines. New boats were developed on their basis, but with replacement of experimental machinery on traditional diesel-electric with strongly increased battery capacity, thanks to what XXI series boats (and XXIII series as their smaller analogue) has received nickname "Elektroboot". The project concept provided for possibility during all route to be in submerged position, never surfacing.

Double-hulled, an outer hull and fin structure had new streamline form, with a minimum of appendages; pressure hull with 28-31mm-thickness amidships had cross-section in the form of "8". A working diving depth was 135m, maximal 200m; minimal diving time was 18sec. Main electric motors worked on shafts through reduction gears. Besides them, there were two low-powered "crouching" motors, ensuring silent 6kts submerged speed. There was a snorkel. Armament included only bow TTs with fast recharge system: theoretically, XXI series submarine could shoot all torpedoes during a half an hour. Instead of 6 torpedoes in TTs submarine can carry 12 TMA mines. Strong artillery have refused, having limited by two twin 30mm MGs (because of unavailability of the latter the majority of boats was commissioned with two twin 20mm MGs) in the streamline cupolas included to CT contours. All boats received sonars and active and passive radars.

Method of building of the boats was also progressive, providing their assemblage from eight large ready sections. It has allowed to moderate building term of one submarine till 176 days and it is significant to shrink work expenditures. Order for first 270 submarines was given out to three manufacturers 6/11/1943 with delivery term by February, 1945; till the end of 1944 828 submarines were totally ordered. Before capitulation of Germany 121 submarines were commissioned, 11 more (U2532, U2547, U3045, U3046, U3047, U3050, U3051, U3531, U3532, U3533 and U3534) have been destroyed during outfitting after launch. After passing trials many boats had to come back to shipyards for elimination of "children's illnesses" that has significantly delayed their ultimate availability, therefore unique XXI-series submarine gone out to route became U2511.

XXI series had many modifications remained on paper. There could been XXIB with 6 side-placed TT directed aft on place of part of spare torpedoes (Nickname "Snow organ"); 83m-long XXIC with 12 side-placed TT directed aft on place of former spare torpedo compartment (submarine had no spare torpedoes!); fuel supplier XXID with 430t of diesel oil in inter-hull space and only 2 bow TT without spare torpedoes (1949t surfaced); transport XXIE carrying 800t of cargo in inter-hull holds (2809t surfaced); fuel supplier XXIV: modification of XXID; transport XXIT (275t of cargo, armament as on XXID).

Modernizations: U2549 was damaged by Allied aircraft 3/5/1945 and scuttled by own crew next day. She was salvaged 3/11/1958 and re-built as type 241 with data as follows:

Wilhelm Bauer 1968

U2540 was scuttled by crew 4/5/1945 at Flensburg, in 1957 she was raised and commissioned by Bundesmarine as Wilhelm Bauer, in 1984 she became a museum.

U3523 was sunk 6/5/1945 by Liberators of 86th RAF sqn in Skagerrack.

Following submarines were scuttled by crews: U2501, U2504, U2505, U3004 and U3506 3/5/1945 at Hamburg; U2507, U2517, U2522, U2525, U2541, U3015, U3044, U3510, U3524, U3526 and U3529 5/5/1945 in Gelting Bay; U2508, U2519, U2520, U2539, U2542, U2543, U2545, U2546, U2548, U2552, U3022, U3028, U3029, U3031, U3038, U3039, U3040, U3505, U3518, U3525 and U3530 3/5/1945 at Kiel; U2510, U2526, U2527, U2528, U2531, U2533, U2535, U2536, U3002, U3010, U3011, U3013, U3016, U3018, U3019, U3020, U3021, U3023, U3025, U3026, U3027, U3037, U3507, U3511, U3513, U3516, U3517, U3521 and U3522 2/5/1945 at Travemünde; U2512 and U3030 8/5/1945 at Eckernförde; U2524 and U2534 3/5/1945 in Mecklenburg Bight E off Fehmarn; U2538 8/5/1945 in Kiel bay at island Aaro; U2544 5/5/1945 in Kattegat SE off Aarhus; U2551, U3033 and U3034 5/5/1945 in Flensburg-fjord; U3001, U3005, U3009, U3047, U3501, U3509, U3527 and U3528 5/5/1945 off Wesermünde; U3006 and U3504 5/5/1945 at Wilhelmshaven; U3014 and U3024 3/5/1945 at Neustadt; U3503 8/5/1945 in Kattegat W off Göteborg.

U2502, U2506, U2511 and U3514 surrendered, and were scuttled by Allies during operation "Deadlight".

Some submarines were transferred on reparations to other countries. USA received U2513 (scuttled 1951) and U3008 (BU 1955). United Kingdom received U3017 (renamed N41, BU 1949). France got U2518 (renamed Roland Morillot, BU 1969). The USSR received U3035 (renamed N-29, then B-29, BU 1958), U2529 (N-28, then B-28, BU 1958), U3041 (N-30, then B-30, BU 1959) and U3515 (N-27, then B-27, BU 1973).