Chapter IV
Opening Moves in Home Waters
3rd September-31st December, 1939

Footnotes

1. See p. 45.

2. See Maps 3 and 22 (facing pp. 63 and 233)

3. See Maps 4 and 5 (facing pp. 65 and 71).

4. See pp. 55-56.

5. See p. 4.

6. See Map 10 (facing p. 97).

7. See Map 4 (facing p. 65)

8. See Map 4 (facing p. 65)

9. See Map 5.

10. See Map 4 (facing p. 65)

11. See Map 6 (facing p. 74).

12. See p. 70.

13. See Map 6 (facing p. 74).

14. An indicator loop consists of a loop of cable laid on the sea bed. The passage of a steel ship over the loop will induce in it a small electric current which is recorded at a shore station. A controlled minefield operates on the same principle, but in this case a row of mines is laid down the centre of the loop and can be fired simultaneously from the shore station when the passage of a ship is detected. The defences of the entrances to important harbours generally included several controlled minefields, with indicator loops further to seaward to give warning of a ship's approach.

15. See p. 70.

16. See Map 7.

17. On that date, in 62° North, 10° West, sunset is at 3.30 p.m. and sunrise at 9.20 a.m. approximately.

18. See Map 7 (facing p. 83).

19. See p. 78.

20. See Map 10 (facing p. 97)