These vessels, under Rear-Admiral Hugh Rodman, arrived in British waters early in December, 1917, and formed a division of the Grand Fleet.

The co-operation afloat was now complete, and all that was needed was further co-operation between the British Admiralty and the United States Navy Department.
This had already formed the subject of discussions, first between Admiral Sims and myself, and later with Admirals Mayo and Benson.
During the summer of 1917 Admiral Sims had been invited to attend the daily meetings of the naval members of the operations side of the Board, an invitation which he accepted, and his co-operation was of great value; but we both felt it desirable to go a step farther, and I had suggested the extreme desirability of the United States Navy Department sending officers of experience of different ranks to work in the Admiralty, both on the operations and material side, officers upon whom the Navy Department could rely to place before us the views of the Department and to transmit their view of the situation as the result of their work and experience at the Admiralty.

We had pressed strongly for the adoption of this course.

Admiral Benson, after discussions, assented to it, and the officers on the material side commenced work in the Admiralty towards the end of 1917, whilst those on the operations side joined the War Staff early in 1918.
It was felt that this course would complete the co-operation between the navies of the two countries and, further, that the United States Navy Department would be kept in the closest possible touch with the British Admiralty in all respects.
It is particularly to be remembered that even before we had established this close liaison the whole of the United States naval forces in British waters had been placed under the command of British naval officers.

This step, so conducive to good results owing to the unity of command which was thus obtained, won our highest admiration, showing as it did a fine spirit of self-effacement on the part of the senior American naval officers.
The visits of Admirals Mayo and Benson to this country were productive of very good results.