The Sub made the necessary alteration in helm. Midnight passed. Portland Light was drawing abeam. According to Vyse's calculations, it ought to have been passed a couple of hours earlier.
"Guess there's a hot tide against us," he remarked. "Or, perhaps we aren't doing nine knots. It's all right so far; we've an ample margin."
The sea had now grown distinctly agitated, although there was little or no wind. Rollo put it down to the backwash from Portland Race, the roar of which was distinctly audible—a disconcerting noise on a dark night. "Now we're closing the Shambles Lightship. We ought soon to pick up Anvil Point. I'll have another look round below and then I'll bring up some hot drinks."
Instead of going down the engine-room hatchway, as before, Vyse made his way for'ard, gaining the saloon direct by means of another hatch. Above the gentle purr of the motors the loud buzzing of a Primus stove was borne to the Sub's ears, a grateful and comforting sound that gave promise of something piping hot within the next ten minutes.
Glancing at his watch, Broadmayne was rather surprised to find that it was nearly two o'clock. By means of rough compass bearings he calculated that the Ibex was about eight miles S.W. by W. of St. Albans. A few minutes later the two powerful lights ashore were blotted out.
About that time a vessel showing white and green navigation lamps passed at not less than a mile away. It was too dark to see what she was like, but the muffled pulsations of an internal combustion engine were distinctly audible.
A dazzling light from the Ibex's motor-room suddenly attracted the Sub's attention. Peering down the half-open hatchway he expected to see Vyse doing inspection work with his electric torch.
To his surprise, he saw that the light came from under the port engine—a steady flare of yellow light that was already licking the sides of the cylinders.
Before Broadmayne could utter a warning shout the steady flame developed into a sheet of fire. A blast of hot air tinged with tongues of ruddy flame shot up through the open hatchway. Yet Vyse gave no indication that he was aware of the peril.
Quitting the wheel, the Sub dashed for'ard. He could see his chum, sublimely unconscious of the inferno raging the other side of the steel bulkhead, crouching over the sizzling frying-pan on the Primus stove.