It was pointed out that in the early stages of the war, the foregoing general dispositions had sufficed to protect the Allies’ communications and to throttle those of the enemy outside the Baltic.  Although enemy cruisers in foreign waters and a few raiding vessels which had evaded the blockade had inflicted losses on trade, losses from such causes could not reach really serious proportions so long as the enemy trusted to evasion and refused to face the Grand Fleet.  The danger of serious loss from attack by raiding surface craft had also been greatly minimized by the adoption of the convoy system.  But as the enemy’s submarines increased in size, efficiency and numbers, the situation had been modified, for evasion by submarines of the command exercised by the Grand Fleet was easy, and our vital sea communications could be attacked by them without the risk of a fleet action.

So far as the protection of trade was concerned, the effect therefore of the submarine campaign had been to remove the barrier established by the Grand Fleet and to transfer operations to the focal areas and approach routes.

As the situation developed, a policy of dealing with the submarines by armed patrol craft and decoy ships in these areas had therefore been put into force.  Merchant ships had been armed as rapidly as possible, and in addition efforts had been made to intercept the submarines en route to these areas both in the vicinity of German waters and farther afield.

The great area covered by the approach routes and the increasing radius of submarine operations had made the provision of a sufficient number of patrol vessels a practical impossibility and had led to a general adoption of the convoy system as rapidly as the supply of fast small craft made this possible.

The methods of attacking German submarines before they could reach open waters, by extensive mining in the Heligoland Bight, with the exception of Dutch and Danish territorial waters, were also mentioned.

As regards future naval policy it was pointed out that the enemy submarine campaign was the dominating factor to such an extent that any sustained increase in the then rate of sinking merchant ships might eventually prove disastrous.

Mention was made of the fact that the enemy was still producing submarines faster than the Allies were destroying them; the policy of coping with submarines after they reached the open sea had not as yet been sufficiently effective to balance construction against losses, even in combination with the extensive minefields laid in the Heligoland Bight.

The future policy was therefore being directed towards an attempt at a still more concentrated and effective control in the areas between the enemy’s ports and our trade routes, and it was proposed to form some description of block or barrage through which the enemy submarines would not be able to pass without considerable risk.  Four forms had been considered: