because of their shallow draft, with a view in the first place to their
pushing the Vindictive, which was to bear the brunt of the work, alongside
Zeebrugge Mole; to the possibility, should the Vindictive be sunk, of
their bringing away all her crew and the landing parties; and to their
ability to maneuver in shallow water or clear of mine fields or torpedoes.
The blocking ships and the Vindictive were especially prepared for their
work long before the start.

Vice-Admiral Sir Roger Keyes devoted personal attention and time to
working out the plan of operations and the preparation of the personnel
and material. Rear Admiral Cecil F. Dampier, second in command of the
Dover flotilla, and Commodore Algernon Boyle, chief of staff, gave
considerable assistance.

When, as vice-admiral of the Dover patrol, Admiral Keyes first began to
prepare for the operation, it became apparent that without an effective
system of smoke screening such an attack could hardly hope to succeed. The
system of making smoke previously employed in the Dover patrol was
unsuitable for a night operation, as this production generated a fierce
flame, and no other means of making an effective smoke screen was
available. Nevertheless Wing Commander Brock, at last devised the way.

The commander-in-chief of the Grand Fleet, Admiral Beatty, sent to Admiral
Keyes a picked body of officers and men. Support also was received from
the neighboring commands at Portsmouth and the Nore, the adjutant general,
Royal Marines, and the depot at Chatham. The rear-admiral commanding the
Harwich force sent a flotilla leader and six destroyers, besides
protecting the northern flank of the area in which operations were to be
conducted.