
Type IXB was an improved
version of type IX with increased range of 1500 nautical miles and
slightly heavier. The designed was improved again in the IXC
type.
This type was the most successful overall with each boat averaging
over 100,000 tons of sinking. They had 22 torpedoes stored which
gave a determined U-boat commander a serious striking power which
could be used night after night against the same convoy, as was
often the case.
Perhaps the most famous IXB boat was the U-123 under the command of
Kptlt. Hardegen which opened up the attack in the US waters in
early 1942 known as Operation Drumbeat. U-107, under the command of
Hessler, made the most successful convoy mission of the war over
with close to 100,000 tons sunk out of Freetown,
Africa.