A large number were ordered, some for anti-submarine work and some for certain contemplated operations in enemy waters, including a night attack on the enemy's light cruisers known to lie occasionally in the Ems River, an operation that it was intended to carry out in the spring of 1918.

A daylight operation in this neighbourhood, which was carried out during 1918, did not, from the published reports, meet with success, the coastal motor boats being attacked by aircraft, vessels against which they were defenceless.

The new boats were of an improved and larger type than the original 40-feet boats.

Delays occurred in construction owing principally to the difficulty in obtaining engines by reason of the great demand for engines for aircraft, and but few of the new boats were delivered during the year 1917.
MINING OPERATIONS The policy which was carried out during 1917 in this respect, so far as the supply of mines admitted, aimed at preventing the exit of submarines from enemy ports.

Incidentally, the fact that we laid large numbers of mines in the Heligoland Bight rendered necessary such extensive sweeping operations before any portion of the High Sea Fleet could put to sea as to be very useful in giving us some indication of any movement that might be intended.