SUBMERGED UNREP FOR SSNs
In glancing through the April1991 SUBMARINE REVIEW. I had a look at Mr. Thompson’s interesting article on Submerged Unrep for SSNs. In it he says that ” … The German WWll method of using “milch cows” for refuelling and resupplying on the surface is clearly unsatisfactory … ” Actually, the Germans went further than this and on several occasions conducted submerged transfers of fuel. The technique involved the two u~ boats meeting on the surface, where the supplying boat streamed a 96m hawser, bose and telephone cable. The buoy was taken aboard the receiving boat, the hawser made fast and the connections made, whereupon both boats submerged to periscope depth, with the supplying boat towing the receiving boat With practice this part of the drill was reduced to some 9 minutes. They then went down to about 35m where speed was increased to 4kts and the transfer of fuel took place, which lasted about 4 hours! Both boats then surfaced together and the tow was dropped. This procedure was first tried by U-460 ( a Type XIV “milch cow”) supplying U-445 (a Type VITC) on 7 December 1942, and was later tested officially in late 1943, using the captured Dutch boat UD-4 (ex~RNetbN 0-26) as the supplying boat, since there were few Type XIVs left. However, the idea seems to have then been dropped.
Of course, this rudimentary procedure differed from Mr. Thompson’s proposal, since he, very sensibly, bases his idea on an entirely submerged meeting and transfer, whereas the Germans bad, perforce, to start and finish the proceedings on the surface. Nevertheless, the germ of the idea was there!