The Portuguese freighter Sines was on the way to Lisbon, after a trip to Philadelphia when, at two o'clock on March 14, 1943, they saw light signals made by four lifeboats that belonged to the American freighter Keystone, sunk hours before by the U-172 .

Among the 71 castaways two had broken legs and others also had minor injuries. All received medical treatment on the Sines, but some were in such a serious condition that the officer’s council decided to divert the ship to the nearest port so they could received the needed care. On the 16th, at 10 am, they were disembarked in Horta, in the Azores, where they were  received by the port doctor, some Red Cross personnel, the local American vice-consul and some other Portuguese authorities.

On the route between Horta and Lisbon, the Sines found four floating corpses in an advanced state of decomposition, which would have originated from another shipwreck.

The Keystone had abandoned the UG.6 convoy with engine problems. On the 12th of March, it still counted with the escort of a destroyer, but when it started to fall behind, the warship had to return to the convoy. On the night of the 13th, two torpedoes shot by U-172 sunk it. Two men were killed in the explosion and the rest were saved in the four lifeboats discovered by the Portuguese.

Carlos Guerreiro