The ship made no attempt to evade the two warships and seemed to wallow, directionless, on the sea. As the crew furled the sail and used oars to manoeuvre closer, Cato could see that the sail was billowing freely. The sheets had been set loose or cut, he decided. The wide beam and high stern were those of a cargo ship and Cato felt briefly disappointed that he had been cheated of finding his prey. There was no sign of life on the deck, and the steering paddle rocked gently from side to side as the waves sloshed against the hull.

To landward, Macro’s ship was making the best use of the offshore breeze to close swiftly before using oars, although he would reach the cargo vessel a short time after the Sobek.

‘Shall I form my lads up, sir?’ asked Centurion Proculus, the commander of the legionaries assigned to the prefect’s ship.

‘No. I’ll use the marines. They’re trained for boarding actions.’

Proculus breathed in sharply, offended at having to give way to men he considered his inferiors. Cato ignored him, well used to the tensions between the two services. Besides, the decision was his. He turned to the decurion in charge of the ship’s complement of thirty marines. ‘Diodorus, have your men formed up ready to board.’

‘Yes, sir. Shall I deploy the corvus?’ He nodded to the contraption lashed to the deck in front of the mast. The corvus was a gangway, which was raised and lowered by a pulley. A wooden pin at one end allowed it to pivot round, over the side of the vessel. At the far end was an iron spike like a crow’s beak. When the device was in position above the target vessel’s deck, it was released and the spike would slam down, piercing the deck and pinning both ships together while the marines rushed across and into action. Although there was no sign of life, Cato decided to stick to convention in case there was a trap waiting to be sprung.

‘Yes. Use the corvus. If you need to be reinforced we can send over the legionaries to settle the issue.’

Proculus puffed up his chest. ‘We’ll get the marines out of any trouble, sir. You can depend on us.’

‘Glad to hear it,’ Diodorus muttered sourly as he made off to issue his orders.

As the Sobek closed on the cargo ship, the deck teemed with armed men taking up their positions. When all was in readiness, they stood still, awaiting the order to go into action. The warship’s trierarch slowed the beat of the sailors manning the oars and cautiously brought his vessel up on the stern quarter of the drifting hulk. When he judged that they were making just enough to carry them down the length of the cargo ship, he shouted the order to ship oars.