“From a legal point of view the subsumption has to consider the time of action. At the time of action the captain had his boat on a rescue and not on acombat mission.”

You did bring up a very interesting point. Allow me to restate your point to see if I understand it.

Is a warship immune from attack when it is engaged in an at-sea rescue operation?

Manual of the Laws of Naval War. Oxford, 9 August 1913, would be a reference. There is nothing in that treaty which would consider, during war, that a warship engaging in at-sea rescue operations would be immune from attack.

[www.icrc.org]

Morally, in my opinion, it would be wrong to attack a ship that is engaged in a rescue operation with the understanding that it would be very difficult for one ship to be both engaged in rescue operations and at the same time, be a viable military thread. But legally,according to the manual, there is nothing illegal about attacking a warship that is engaging in an at-sea rescue operation.

The Hague conventions of 1907 only protect neutral vessels and registered hospital ships from attacks during rescue operations.

My position remains unchanged. While it may have been immoral for the bomber crew to attack the U-156 during its rescue operations, it was not illegal.

Can you cite a treaty or law that refutes my position?

This brings up another interesting argument.

The Italians were POWs of the allies. Under T”he Convention relative to the Treatment of Prisoners of War”. Geneva, 27 July 1929, POWs are to be protected from attacks from either the native forces or the hostile forces. An argument could be made that the bombing of allied POWs (the Italian POWs in the lifeboats) was a violation of this convention.

[www.icrc.org]

This argument would be worthy of discussion, in my opinion.

It could be humourous, in a sick sort of way, to consider whether the transfer of the Allied controlled POWs from the Laconia to the U-156 could be considered an escape attempt. But I seriously doubt this could be a valid argument.