12 May 1943 the I.J.N. submarine I-31 under command of Inoue was sunk by USS EDWARDS (DD 265) and USS FARRA GUT (DD 348) off the Aleutian Islands.

14 May 1943 the I.J.N. submarine Ro-102 under command of Kanemoto was sunk by the American PT-150 and PT-152 at 06.55S x 147.34E.

29 May 1943 the I.J.N. submarine I-178 under command of Uts'ki was sunk by SC-669 at 15.3 5 S x 167.17E

13 May 1943 the Italian submarine MOCENIGO was sunk by planes of the USAAC off Cagliari, Sardinia.

21 May 1943 the Italian submarine GORGO was sunk by USS NIELDS (DD 616) at 36.01N x 00.34W.

23 May 1943 the Italian sub. LEONARDO da VINCI was sunk by HMS ACTIVE and HMS NESS at 42.16N x 15.40W

What were the German losses in this same month?

U-332, U-659, U-439, U-640, U-192, U-638, U-125, U-531 U-438, U-465, U-447, U-109, U-663, U-528, U-186, U-89 U-456, U-266, U-640, U-753, U-176, U-463, U-182, U-128 U-647, U-646, U-954, U-209, U-273, U-381, U-258, U-303 U-569, U-752, U-414, U-467, U-436, U-304, U-755, U-563 and U-440 a total of 41 submarines lost in this one month alone!

In May of 1943, the submarine losses were:

Germany 41 submarines
Japan 3 submarines
Italy 3 submarines

A total of 47 submarines, most with the loss of all hands aboard, something in excess of 2,000 men! Compare that with American submarine losses for the same month -- one submarine!

USS RUNNER (SS 275) on 28 May 1943.

The handwriting was on the wall - and Black May had arrived. The AXIS submarine commands (especially the German BdU) were not aware that the codes had been broken and the whereabouts of just about every AXIS submarine was known to the Allies. It was an easy task to send the bombers or the Hunter-Killer groups to the very spot where the AXIS submarine was lying. The hunting was done by the code-breakers; the killing was easy once the positions were known. Black May was definitely the beginning of the end of the U-Boat war.

From this point onward, life expectancy of the German U-Boat was a single one-way patrol. Barely one U-Boat in ten returned from their first patrol. Usually the first patrol was a one way ride but even knowing this, there is not one single report of anyone refusing to go on war patrol - they knew their chances were almost non-existent, but they got into their iron coffins and put to sea because it was their duty. The U-Bootwaffe was the only over-subscribed of the German services all the way to the end of the war. Their bravery was never questioned.