Typ II coastal U-boat
The Einbaume (dug-out
canoes) were the first U-boats built by Germany after WWI and the first
batch (six IIA's) were near-copies of the Finnish Vesikko submarine (p.W:MP123), wich
was tested by the Germans before being sold to Finland. Even as those
were under construction an improved version was being designed. The
first of the Typ IIB's entered service in 1936, as did all of the Typ
IIA's. These boats were inadequate for the demands of WWII, but due to
the shortage of larger and newer U-boats in 1939, the Typ II's in
service were pressed into combat duties. Some of these boats (six IIBs)
were disassembled at their North Sea bases and were transported across
continental Europe, to be reassembled and used in the Black Sea (five
of the six were scuttled late in the war rather than letting them be
captured by the Soviets). Most of the Typ II's were, at one point or
another, used for training, which explains why out of a total of 50
boats constructed only eleven were lost in combat (another four were
lost in training accidents). Most Typ VII (p.W:IC91) commanders got
their start in a Typ II.
Typ IIB's sank or damaged around 115 ships in some 160 combat
patrols, although most of these were of smaller ships. The U-10, U-18,
U-19, U-20, U-23 and U-24 all went on at least 14 combat patrols each
(U-19 and U-24 tied with the most at 20 each). Two boats of this class,
the U-120 and U-121, were intended for export when first laid down, but
by the time they were completed in 1940 they were required by the
Germans; neither saw combat (as well as the U-11 and possibly U-8),
both only being used as training boats and scuttled in 1945.
The Typ IIB has a crew of 25. It mounts three 21” torpedo tubes forward. A 20mm AA gun is carried on a pedestal on the foredeck. The engines burn 20.9 gallons of diesel fuel per hour of routine usage. The Typ IIB can travel 1,500 miles at 15 mph surfaced and 40 miles at 5 mph submerged.
Subassemblies: Very Light Corvette chassis with Sub
option
+7; sealed Medium TD superstructure [Body:T] +3; full-rotation Mini
open mount [Sup:T] +1.
Powertrain: 2¥261-kW marine diesel engines with
2¥261-kW water screws and 3,600-gallon standard tanks;
2¥134.5-kW
electric motors with 1.05 million-kWs batteries†.
Occupancy: 8 CS Body, 3 CS Sup Cargo:
1,083 Body, 29 Sup
Armor
Body: 4/45
Sup: 4/45
OM: 0/0
Weaponry
3¥533mm Torpedo Tubes [Body: F] (6).
20mm Long Ground AC [OM:F] (2,000).
Equipment
Body: Autopilot; backup driver controls; 500-VSP bilge;
5¥bilge
pumps†; 16¥bunks; 50-VSP cargo holds; 25-man environmental
control†; 5¥fire extinguishers†; 25-man-days life support†;
navigation instruments;
precision navigation instruments; 250-man/days of provisions; 1-mile
passive
sonar. Sup: Navigation instruments; 1¥25’ 15¥
periscope; medium and large radio receivers and transmitters;
searchlight. OM:
Universal mount.
† Limited access.
Statistics
Size: 134’¥13’¥29’ | Payload: 92.5 tons | Lwt: 329 tons |
Volume: 3,951 |
Maint.: 17 hours | Price: $131,000 |
HT: 12
HP: 27,000 [Body], 360 [Superstructure], 30 [Open Mount]
wSpeed: 15 |
wAccel: 0.1 | wDecel: 0.5(0.6) | wMR: 0.05 | wSR: 3 |
Draft: 13' |
uSpeed: 8 |
uAccel: 0.05 | uDecel: 0.3(0.4) | uMR: 0.05 | uSR: 4 |
uDraft: 45' |
Design Notes
The 329-ton historical submerged displacement was used for underwater
performance
calculations. Design wSpeed was 10 mph, uSpeed was 10 mph and design
Draft 7 feet; the historical
figures were used instead. As the chassis used was oversized for
the design, most of the empty space should be ignored. One source lists
length as 144'.
wSR was lowered as the boat was known to roll excessively on the
surface.
For patrols (as opposed to training) up to four 20mm guns were
mounted (the extra guns on pedestals on the deck). Up to eight mines
could be carried in place of the torpedoes.
Variants
The Typ IIA (1936) displaced 302 tons dived and was 134' long. It had a
surface range of only 1,200 miles. Six built.
The Type IIC (1938) was 341 tons dived and 144' long. The longer
hull was also iused to improve the radio room and add a second
periscope, apart from the additional fuel stores. The propellers were
shrouded; while this appeared to cause no problems in service, it was
not repeated on any other class of U-boats. Surface range was 2,200
miles and surface speed was 14 mph. Elecric motors increased to 306-kW
total but submerged speed and range was the same as the IIB. Eight
built.
The Typ IID (1940) was basically the same as the IIC, but with
self-compensating saddle tanks (beam 16') for greatly improved range
(4,025 miles), increasing displacement to 364 tons. As diesel was drawn
from the saddle tanks, seawater was let in, maintaining positive
buoyancy. With this greatly increased ranged, the IID's patrolled as
far as the shores of Western Britain. batteries were also improved,
allowing a range of 63 miles at 5 mph. Speed was back up to 15 mph.
Sixteen built.