and have succeeded in unknown ways in evading and cutting
through nets and obstructions.
27. In addition to submarines, heavy forces are free to raid, and in fact escape through, the Channel at any time when the enemy decides that the necessity or return will justify the risk. Hence the suggestion that two divisions of our fast Dread- noughts might be based upon Brest, primarily for the resulting moral effect against such possible raids.
I was told yesterday by an important Admiralty official that while he thought the chances of raids in, or escape through, the Channel by heavy enemy forces out of reach of the Grand Fleet (North of Scotland) were very remote, nevertheless the possibility existed and was principally thwarted on moral grounds, that is, the uncertainty in his mind of the opposition which would be encountered. He agreed with others, including the First Sea Lord, that the addition of some of our heavy forces to those maintained in southern Channel approaches by the French and British would undoubtedly entirely preclude the possibility of such raids.
28. Submarine Losses :
It has been found necessary to accept no reports of submarine losses as authentic and certain unless survivors are captured or the submarine itself is definitely located by dragging. No dependence even is placed upon evidence of oil on the surface after a submarine has been attacked and forced down, as there is reason to believe that when an enemy submarine dives to escape gunfire she is fitted to expel oil for the particular purpose of conveying the impression that she has been sunk and thereby avoid further pursuit. It has been shown that the amount of damage a submarine can stand is surprising and much more than was anticipated before the experience of the war. Upon a recent occasion a British submarine was mistaken for an enemy and though struck by several shells, dived and escaped to port. The submarine losses which are certain since outbreak of war are as given in attached cablegram.
It is estimated that between thirty and forty submarines operate at a time in the waters surrounding the British Islands and French Coast. At least one is now known to be on White Sea trade lanes.
29. Best anti-submarine weapons :
One of the most efficient weapons now used by all destroyers and patrol craft against submarines is the so-called "Depth Charge," sample and drawings of which have been forwarded by our Naval Attache. These are merely explosive charges designed to explode at a certain depth, formerly eighty feet, now about one hundred feet. They are dropped overboard where a submarine that has submerged is assumed to be and
