The Admiralty was heart and soul for an audacious policy, providing the form of attack and the occasion offered a reasonable prospect of success.

Owing to the preoccupations of the Army, we had to be satisfied with bombardments of the ports by unprotected monitors, which had necessarily to be carried out at very long ranges, exceeding 25,000 yards, and necessitating direction of the fire by aircraft.
Bruges, about eight miles from the sea, was the real base of enemy submarines and destroyers, Zeebrugge and Ostend being merely exits from Bruges, and the use of the latter could only be denied to the enemy by land attack or by effective blocking operations at Ostend and Zeebrugge, for, if only one port was closed, the other could be used.
Neither Zeebrugge, Ostend, nor Bruges could be rendered untenable to the enemy with the guns available during 1917, although Ostend in particular, and Zeebrugge to a lesser extent, could be, and were frequently, brought under fire when certain conditions prevailed, and some temporary damage caused.

Indeed, the fire against Ostend was so effective that the harbour fell into disuse as a base towards the end of 1917.

We were arranging also in 1917 for mounting naval guns on shore that would bring Bruges under fire, after the enemy had been driven from Ostend by the contemplated operation which is mentioned later.

When forced to abandon this operation, in consequence of the military advance being held up by the weather, these guns were mounted in monitors.
In the matter of blocking the entrance to the ports of Zeebrugge and Ostend, the fact had to be recognized that effective _permanent_ blocking operations against destroyers and submarines were not practicable, mainly because of the great rise and fall above low water at ordinary spring tides, which is 14 feet at Ostend and 13 feet at Zeebrugge for about half the days in each month.