Zachary had to acknowledge the truth of this. 'No, Mr Crowle. I didn't.'

'Care to go out in the gig and take a look?'

Zachary paused, trying to reckon whether he would have time enough to get to the buoy and back before the wave came bearing down. It was hard to judge because of the current, which was flowing so swiftly as to carve deep fissures on the river's surface.

As if to preclude his doubts, the first mate said: 'Not a nidget are ye, Reid?'

'No, Mr Crowle,' Zachary said promptly. 'I'll go if you think it's necessary.'

'Stubble yer whids then, and heave on.'

If he was to do it, Zachary knew he would have to be quick. He went aft at a run, heading for the stern where the gig was still tethered – pulling it out of the water was to have been the last item in the preparations for the bore. Looking at it now, Zachary decided that it would take too long to draw the boat around to the side-ladder: better, if trickier, to vault over the stern-rail. He was tugging on the boat's painter when Serang Ali stepped out of the wheel-house to whisper: 'Malum 'ware: gig-bot broken.'

'What…?'

Zachary's question was cut short by the first mate, who had followed him aft: 'What's this now? Fraid o' wettin yer feet, Mannikin?'

Without another word, Zachary handed the gig's painter to Serang Ali who looped it around a stanchion and pulled it taut. Climbing over the stern-rail, Zachary took hold of the rope and lowered himself into the gig, signalling to Serang Ali to set the boat loose. Almost at once the current took hold of the little craft and pulled it along the length of the schooner, propelling it towards midstream.

The gig's oars were on the floorboards and on reaching for them, Zachary was surprised to find that there was a good inch or so of water sloshing around the bottom. He thought nothing of it, for the boat's sides were so low that waves often lapped over them, even when the craft was stationary. When he began to row, the gig responded well enough until he was some twenty feet past the schooner's bow. He noticed then that the water in the boat's bottom had risen past his ankles and was creeping up his calves. He had, so far, concentrated his attention on the buoy, so he was taken aback when he looked over the gig's side – for only an inch or two remained between the gunwale and the fast-flowing river. It was as if holes had been drilled into the gig's hull, with great care, so as not to open up fully until the boat was under oar.

He pushed his shoulders hard against the oars now, trying to turn the gig about, but the stern was wallowing so deep in the water that the bows would not respond. The buoy was only some twenty feet ahead, clearly visible even in the rapidly dimming light, but the current was sweeping the boat wide of its mark, towards the middle of the river. The schooner's cable was tantalizingly close and Zachary knew that if he could but reach it, he would be able to pull himself to safety. But the gap was widening quickly, and although he was a strong swimmer, Zachary guessed that it would not be easy to get to the cable before the wave swept in, not with the current flowing against him. Clearly, his best hope lay in being picked up by another boat – but the Hooghly, usually so tightly packed with river craft, was ominously empty. He looked towards the Ibis and saw that Serang Ali knew he was in trouble. The lascars were labouring to lower the starboard longboat – but there was nothing to be hoped for here, for the process could take as much as fifteen minutes. Glancing shore-wards, he saw that he was being observed by a great number of spectators – fishermen, boatmen and others – all of whom were watching with helpless concern. The sound of the approaching bore was clearly audible now, loud enough to leave no doubt that anyone who ventured into the water would do so at the risk of his life.

This much was clear: it wouldn't do to remain in the foundering gig. Using his toes and heels, Zachary worked his sodden shoes off his feet and tore off his canvas shirt. Just as he was about to jump, he saw a boat sliding down the mudbank: the slim, long craft hit the water with such force that its momentum carried it halfway to Zachary.

The sight of the boat lent Zachary's arms a burst of strength, and he did not pause for breath until he heard a voice, shouting: 'Zikri Malum!' He raised his head from the water and looked up to see a hand reaching towards him; looming behind it was Jodu's face; he was stabbing a finger to point downriver, where the sound of the wave had risen to a rumble. Zachary didn't stop to listen; snatching at Jodu's hand, he tumbled into the boat. Pulling him upright, Jodu thrust an oar into his hands and pointed to the buoy ahead: the wave was too close now to think of rowing back to shore.

As he dug his oar into the water, Zachary threw a glance over his shoulder: the wave was streaking towards them and its foaming crest was a blur of white. He turned away, rowing furiously, and did not look back again till they had drawn level with the buoy. Behind them, the bore was rearing out of the water at an impossible angle, as if springing into a leap.

'Zikri Malum!' Jodu had already leapt on the buoy and was knotting the boat's rope to the hooped holdfast on its crown. He gestured to Zachary to leap too, extending a hand to steady him as he stepped on the slippery, algae-covered surface.

Now, with the wave almost upon them, Zachary threw himself flat, beside Jodu. There was just enough time to pass a rope around their bodies and loop it through the holdfast. Linking one arm with Jodu's, Zachary hooked the other through the iron hoop and sucked a huge draught of air into his lungs.

Suddenly everything went quiet and the wave's deafening sound was transformed into an immense, crushing weight, flattening them against the buoy, holding them down so hard that Zachary could feel the barnacles on its surface slicing into his chest. The heavy float strained against its cable, spinning around and around as the water swept past. Then suddenly, like a windswept kite, it changed direction and shot upwards, with a momentum that lifted it out of the water with a skip and a bounce. Zachary shut his eyes and let his head fall against the metal.

When his breath returned, he extended his hand to Jodu. 'Thank you, my friend.'

Jodu flashed him a grin and grasped his hand with a slap: eyebrows dancing wildly in his face, he said, 'Cheerily there! Alzbel!'

'Sure,' said Zachary with a laugh. 'Alzbel that's end's well.'

Miraculously Jodu's boat had survived unscathed and he was able to row Zachary back to the Ibis before going off to return the hired craft to its owner.

Zachary hauled himself aboard the schooner to find the first mate waiting, with his arms crossed over his chest. 'Had enough, Reid? Changed yer mind yet? Still time to turn around and get y'self ashore.'

Zachary glanced down at his dripping clothes. 'Look at me, Mr Crowle,' he said. 'I'm here. And I'm not going anywhere the Ibis isn't going.'