The bilge pump is dependent on the main engine.

To use the pump it was necessary to go ahead.

It was at such times that the heaviest seas swept in over the lee rail; over and over [again] the rail, from the forerigging to the main, was covered by a solid sheet of curling water which swept aft and high on the poop.

On one occasion I was waist deep when standing on the rail of the poop.
The scene on deck was devastating, and in the engine-room the water, though really not great in quantity, rushed over the floor plates and frames in a fashion that gave it a fearful significance.
The afterguard were organised in two parties by Evans to work buckets; the men were kept steadily going on the choked hand pumps--this seemed all that could be done for the moment, and what a measure to count as the sole safeguard of the ship from sinking, practically an attempt to bale her out! Yet strange as it may seem the effort has not been wholly fruitless--the string of buckets which has now been kept going for four hours, [1] together with the dribble from the pump, has kept the water under--if anything there is a small decrease.
Meanwhile we have been thinking of a way to get at the suction of the pump: a hole is being made in the engine-room bulkhead, the coal between this and the pump shaft will be removed, and a hole made in the shaft.

With so much water coming on board, it is impossible to open the hatch over the shaft.