A closer launch point gave the canoe crews another hour of favourable tide. It required HMS Tuna to come to full buoyancy four miles from the coast and ten miles from a radio direction-finding station, dispensing with the planned approach at low buoyancy. RAF-laid mines constrained the possible routes. Raikes complained that their positions interfered with every plan and distrusted the accuracy of the coordinates supplied. The benefit to the canoe crews therefore depended on knowing the submarine's position precisely.
Notable Point · 1:21:12-1:23:12
A closer canoe launch required precise navigation around RAF mines
Moving Tuna closer gave the canoe crews another hour of favourable tide, but exposed the submarine near shore and demanded accurate navigation around uncertain mine positions.