Watching carefully that loose lumps of ice did not damage the propeller, we would reverse the engines and back the ship off 200 to 300 yds.

She would then be driven full speed into the V, taking care to hit the centre accurately.

The operation would be repeated until a short dock was cut, into which the ship, acting as a large wedge, was driven.

At about the fourth attempt, if it was to succeed at all, the floe would yield.

A black, sinuous line, as though pen- drawn on white paper, would appear ahead, broadening as the eye traced it back to the ship.