While she swung her bows from the foaming turmoil the next swept her deck.

But to watch the seas and keep the hulk in line was the captain's business, and Lister was occupied by his.
Standing on a slanted platform with his hand on the throttle, he waited for the lurch that lifted the spinning screw.

When the blades left the water, the engines raced with a horrible din and he must cut off steam.
If he let the engines go, something might break when the propeller got hold again.

The work demanded a firm but delicate touch, since the pressure must change with the swiftly-changing load.

One could not argue when the bows would plunge and the stern swing clear; one must know instinctively.