The well-known MILCH-KUH (Milk Cow) that was a sea-going submarine tanker to resupply the Frontboots, thus allowing them to remain on station far longer than they could on their own legs; their own fuel supply. These boats were rather tubby by comparison with the sleek Frontboots, but they were meant for a different job. In addition to the enormous fuel they carried for Frontboots, they also carried a few spare torpedoes for resupply.

Displacement 1,688/1,932 tons
Dimensions 220.5 x 30.75 x 21.25 feet
Power twin-shaft diesel/electric
Power(diesel) 2,800hp
Power(electric) 750hp
Speed (diesel) 14.5 knots
Speed (electric) 6.25 knots
Bunkers (boat’s fuel) 203 tons
Bunkers (to resupply Frontboots) 432 tons
Radius (diesel) 9,300 miles @ 12 knots
Radius (electric) 53 miles @ 4 knots
Tubes (fwd and aft) none (carried four torpedoes for resupply)
Guns no deck guns
AA Guns single 2.0 cm AA and two 3.7cm AA (the 3.7 cm were positioned one ahead and one abaft the tower)
Crew 53

The life expectancy of the MILCH-KUH was very short, as they were a top priority target for the ASW forces for obvious reasons and because of the apparent lack of security of the crews of these boats. We were told by a crewman of a TYPE IX-C Frontboot that, when they took on fuel from a MILCH-KUH along with another IX-C boat; that the two Frontboots had men immediately on the AA guns and double look-outs on the tower while the AA guns of the TYPE XIV swung unmanned on their mounts; there were no look-outs in the tower and the crewmen on deck lounged at the rail as they smoked cigarettes.