The return journey out of the gorge would be just as slow, Hereward thought, and entailed much greater risk. If they lost too many rowers in battle, and if the wind failed to come up, they might well not make it out before the eagre came racing up the gorge once more.

He tried to dismiss images of the great wave roaring down the gorge as he climbed up the side of the bomb vessel and quickly ran to the mortar. His crew had everything ready. The chest was open to show the special bomb, the charge bags were laid on oil-cloth next to it and his gunner’s quadrant and fuses were laid out likewise on the opposite side.

Hereward looked up at the sky and at the marks Fitz had sorcerously carved into the cliff the month before, small things that caught the moonlight and might be mistaken for a natural pocket of quartz. Using these marks, he ordered a minor adjustment of the springs to warp the bomb vessel around a fraction, a task that took precious minutes as the crew heaved on the lines.

While they heaved, Hereward laid the carefully calculated number and weight of charge bags in the mortar. Then he checked and cut the fuse, measuring it three times and checking it again, before pushing it into the bomb. This was a necessary piece of misdirection for the benefit of the pirates, for in fact Fitz had put a sorcerous trigger in the bomb so that it would explode exactly as required.

“Load!” called Hereward. The six pirates who served the mortar leaped into action, two carefully placing the wadding on the charge bags while the other four gingerly lifted the bomb and let it slide back into the mortar.

“Prepare for adjustment,” came the next command. Hereward laid his gunner’s quadrant in the barrel and the crew took a grip on the two butterfly-shaped handles that turned the cogs that would raise the mortar’s inclination. “Up six turns!”