Sir, – Having read Richard Sharpe’s review of The U-Boat Commanders Knight’s Cross Holders 1939-1945 (NR107/4) I wish to make the following observations. From the start Mr Sharpe sets out to make the U-Boat Commanders despicable villains and suggests we may even be “repelled” by the fact they were decorated for their actions of “sinking and killing unarmed merchant ships and their crews.” He then goes on to say how “distasteful” it is to measure “courage and valour” by sinking tonnage and “the killing of men who could not fight back.” Not strictly true as many merchant ships were armed with gu…