SETTER stayed on the surface all that night. She passed through her waiting position at about two thirty in the morning, but MacGregor had decided to carry on northwards to the top edge of the allotted area so that the next day’s dived patrol could be on a southerly course and bring her back to the centre, the cross on the chart. He wanted to be there around midnight each night, because it was at that hour they could expect the signal to come, when it did, and then they’d be right on the spot - or within a few miles of it - where the Admiral (Submarines) in his headquarters at Northolt would expect them to be.
By diving at five in the morning, Setter would have a run back of twenty-five miles, which would be just about the right distance: twelve hours at an average speed, dived, of about
