Sister ship to the Vytura and the Varella, also accompanying her in FR77, the Cochella carried over 3,000,000 gallons of 100-octane petrol.
She was hit by at least three torpedoes: the first two broke her almost in half, the third triggered off a stupendous detonation that literally blew her out of existence.
One moment she was there, sailing serenely through the limpid twilight of sunrise: the next moment she was gone.
Gone, completely, utterly gone, with only a seething ocean, convulsed in boiling white, to show where she had been: gone, while stunned eardrums and stupefied minds struggled vainly to grasp the significance of what had happened: gone, while blind reflex instinct hurled men into whatever shelter offered as a storm of lethal metal swept over the fleet.
Two ships took the full force of the explosion.
A huge mass of metal-it might have been a winch-passed clear through the superstructure of the Sinus, a cable-length away on the starboard: it completely wrecked the radar office.
What happened to the other ship immediately astern, the impossibly-named Tennessee Adventurer, was not clear, but almost certainly her wheelhouse and bridge had been severely damaged: she had lost steering control, was not under command.
Tragically, this was not at first understood, simply because it was not apparent.
Tyndall, recovering fast from the sheer physical shock of the explosion, broke out the signal for an emergency turn to port.
The wolf-pack, obviously, lay on the port hand, and the only action to take to minimise further losses, to counter the enemy strategy, was to head straight towards them.
He was reasonably sure that the U-boats would be bunched-generally, they strung out only for the slow convoys.
Besides, he had adopted this tactic several times in the past with a high degree of success.
Finally, it cut the U-boats' target to an impossible tenth, forcing on them the alternative of diving or the risk of being trampled under.
With the immaculate precision and co-ordination of Olympic equestrians, the convoy heeled steadily over to starboard, slewed majestically round, trailing curved, white wakes phos-phorescently alive in the near-darkness that still clung to the surface of the sea.
Too late, it was seen that the Tennessee Adventurer was not under command.
Slowly, then with dis-, maying speed, she came round to the east, angling directly for another merchantman, the Tobacco Planter.
There was barely time to think, to appreciate the inevitable: frantically, the Planter's helm went hard over in an attempt to clear the other astern, but the wildly swinging Adventurer, obviously completely out of control, matched the Planter's tightening circle, foot by inexorable foot, blind malice at the helm.
She struck the Planter with sickening violence just for'ard of the bridge.
The Adventurer's bows, crumpling as they went, bit deeply into her side, fifteen, twenty feet in a chaos of tearing, rending metal: the stopping power of 10,000 tons deadweight travelling at 15 knots is fantastic.
The wound was mortal, and the Planter's own momentum, carrying her past, wrenched her free from the lethal bows, opening the wound to the hungry sea and hastened her own end..Almost at once she began to fill, to list heavily to starboard.
Aboard the Adventurer, someone must have taken over command: her engine stopped, she lay almost motionless alongside the sinking ship, slightly down by the head.
The rest of the convoy cleared the drifting vessels, steadied west by north.
Far out on the starboard hand, Commander Orr, in the Sirrus, clawed his damaged destroyer round in a violent turn, headed back towards the crippled freighters.
He had gone less than half a mile when he was recalled by a vicious signal from the flagship.
Tyndall was under no illusions.
The Adventurer, he knew, might remain there all day, unharmed-it was obvious that the Planter would be gone in a matter of minutes-but that would be a guarantee neither of the absence of U-boats nor of the sudden access of misguided enemy chivalry: the enemy would be there, would wait to the last possible second before dark in the hope that some rescue destroyer would heave to alongside the Adventurer.
In that respect, Tyndall was right.
The Adventurer was torpedoed just before sunset.
Three-quarters of the ship's company escaped in lifeboats, along with twenty survivors picked up from the Planter.
A month later the frigate Esher found them, in three lifeboats tied line ahead, off the bitter, iron coast of Bear Island, heading steadily north.
The Captain, alert and upright, was still sitting in the stern-sheets, empty eye-sockets searching for some lost horizon, a withered claw locked to the tiller.
The rest were sitting or lying about the boats, one actually standing, his arm cradled around the mast, and all with shrunken sun-blackened lips drawn back in hideous mirth.
The log-book lay beside the Captain, empty: all had frozen to death on that first night.
The young frigate commander had cast them adrift, watched them disappear over the northern rim of the world, steering for the Barrier.
And the Barrier is the region of the great silence, the seas of incredible peace, so peaceful, so calm, so cold that they may be there yet, the dead who cannot rest. A mean and shabby end for the temple of the spirit.... It is not known whether the Admiralty approved the action of the captain of the frigate.
But in the major respect, that of anticipating enemy disposition, the Admiral was utterly wrong.
The wolf-pack commander had outguessed him and it was arguable that Tyndall should have foreseen this.
His tactic of swinging an fast, highly manoeuvrable, impeccably handled, bobbed and weaved their way to safety with almost contemptuous ease, straightened up and headed south under maximum power.
The merchant ships, big, clumsy, relatively slow, were less fortunate.
Two ships in the port line, a tanker and a freighter, were struck: miraculously, both just staggered under the numbing shock, then kept on coming.
Not so the big freighter immediately behind them, her holds crammed with tanks, her decks lined with them.
She was torpedoed three times in three seconds: there was no smoke, no fire, no spectacular after-explosion: sieved and ripped from stern to stem, she sank quickly, quietly, still on even keel, dragged down by the sheer weight of metal.
No one below decks had even the slightest chance of escaping.
A merchantman in the centre line, the Belle Me, was torpedoed amidships.
There were two separate explosions, probably she had been struck twice-and she was instantly on fire.
Within seconds, the list to port was pronounced, increasing momentarily: gradually her rails dipped under, the outslung lifeboats almost touching the surface of the sea.
A dozen, fifteen men were seen to be slipping, sliding down the sheering decks and hatch covers, already half-submerged, towards the nearest lifeboat.
Desperately they hacked at belly-band securing ropes, piled into the lifeboat in grotesquely comical haste, pushed it clear of the dipping davits, seized the oars and pulled frantically away.
From beginning to end, hardly a minute had elapsed.
Half a dozen powerful strokes had them clear beyond their ship's counter: two more took them straight under the swinging bows of the Walter A.