The Crisis of the Naval War

by John Rushworth Jellicoe

Port of Assembly. Frequency of Sailing. Destination.
Lamlash Every 4 days. Atlantic ports.
Milford Haven Every 4 days. Gibraltar.
Queenstown Every 4 days. Atlantic ports.
Falmouth Every 8 days. Gibraltar.
Plymouth Every 4 days. Atlantic ports.

About 150 vessels sailed every eight days in convoys varying in strength from 12 to 30 ships.

There was still a good deal of Atlantic trade that was not sailing under convoy. This comprised trade between Gibraltar and North and South America, between the Cape, South America and Dakar, and the coastal trade between North and South America. It was estimated that an additional twenty-five to thirty ocean escorts and eleven destroyers would be needed to include the above trade in convoy.

The Mediterranean trade is dealt with later.

The question of speed was naturally one of great importance in the convoy system. As has been stated earlier, the speed of a convoy like that of a squadron or fleet is necessarily that of the slowest ship, and in order to prevent delay to shipping, which was equivalent to serious loss of its carrying power, it was very necessary that convoys should be composed of ships of approximately the same speed. In order to achieve this careful organization was needed, and the matter was not made easier by the uncertainty that frequently prevailed as to the actual sea speed of particular merchant ships. Some masters, no doubt from legitimate pride in their vessels, credited them with speeds in excess of those actually attained. Frequently coal of poor quality or the fact that a ship had a dirty bottom reduced her speed to a very appreciable extent, and convoy commodores had occasionally to direct ships under such conditions to drop out of the convoy altogether and make their passage alone. Obviously this action was not taken lightly owing to the risk involved. Decision as to the sea speed of convoys was taken by the convoy officer at the collecting port, and he based this on the result of an examination of the records in the different ships. As a rule convoys were classed as "slow" and "fast." Slow convoys comprised vessels of a speed between 8 and 12-½ knots. Fast convoys included ships with a speed between 12-½ and 16 knots. Ships of higher speed than 16 knots did not as a rule sail in convoys, but trusted to their speed and dark hours for protection in the submarine area. The Gibraltar convoy (an exception to the general rule) contained ships of only 7 knots speed.

With the introduction of convoys the provision of efficient signal arrangements became a matter of importance. The issue of printed instructions to each master and the custom introduced of assembling the masters to meet the captain of the escorting cruiser before sailing, so that the conduct of the convoy might be explained, had the effect of reducing signalling to a minimum, but it was necessary that each ship should have a signalman on board, and the provision of the number of signalmen required was no easy matter. A good wireless installation was essential in the escorting cruiser and in the Commodore's ship in order that the course of the convoy could be diverted by the Admiralty if the known or suspected presence of submarines rendered it necessary, and also for the purpose of giving to the Admiralty early information of the position of a convoy approaching the coast, so that the escorting destroyers could be dispatched in time.

Fortunately for us, German submarines constantly used their wireless installations when operating at sea, and as a consequence our wireless directional stations were able to fix their positions by cross bearings. This practice on the part of the enemy undoubtedly went far to assist us both in anti-submarine measures and in diverting trade to a safe course.

The introduction of the convoy system rendered the provision of anti-submarine protection at ports of assembly a matter of great importance, owing to the very large number of vessels that were collected in them. Some of the ports were already in possession of these defences, but amongst those for which net protection was prepared and laid during 1917 were Halifax, Sydney (Cape Breton), Falmouth, Lamlash, Rosslare (on the south-east coast of Ireland), Milford Haven, Sierra Leone and Dakar. This involved extensive work, and was undertaken and carried out with great rapidity by Captain F.C. Learmonth and his staff, whose work in the production of net defences during the war was of inestimable value, not only to ourselves, but to our Allies, for whom large supplies of net defences were also provided. The U.S.A. also adopted our system of net defence for their harbours on entry into the war. Many anxious months were passed at the Admiralty and at the ports named until the anti-submarine defences were completed.

The escort of the convoys through the submarine zone imposed very heavy work upon the destroyers, sloops and other screening vessels. This was due partly to the fact that there were not sufficient vessels to admit of adequate time being spent in harbour to rest the crews and effect necessary repairs, and partly to the nature of the work itself and the weather conditions under which so much of it was carried out. It will be realized by those who have been at sea in these small craft that little rest was obtainable in the Atlantic between the west coast of Ireland and the mouth of the Channel and positions 800 to 400 miles to the westward, except in the finest weather. When to this is added the constant strain imposed by watching for the momentary appearance of a periscope or the track of a torpedo, and the vigilance needed, especially on dark and stormy nights, to keep touch with a large convoy of merchant ships showing no lights, with the inevitable whipping up of occasional stragglers from the convoy, some idea may be gathered of the arduous and unceasing work accomplished by the anti-submarine escorts.

It had been my practice during 1917 to call for returns from all commands of the number of hours that vessels of the destroyer and light cruiser type were actually under way per month, and these returns showed how heavy was the strain on the destroyers, particularly those engaged in convoy work.