-where training especially adapted to the plan
of operation was given--and the organization of the expedition was carried
on.

The material as it was prepared was used to make the training practical
and was itself tested thereby. Moreover, valuable practice was afforded by
endeavors to carry out the project on two previous occasions, on which the
conditions of wind and weather compelled its postponement, and much was
learned from these temporary failures.

The Hindustan, at first at Chatham and later at the Swim, was the parent
ship and training depot. After the second attempt, when it became apparent
that there would be a long delay, the Dominion joined the Hindustan and
the pressure upon the available accommodation was relieved by the transfer
of about 350 seamen and marines to her.

Two special craft, Liverpool ferry steamers, Iris and Gloucester, were
selected after a long search by Captain Herbert Grant. They were selected
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