Edward's intentions were well known; he wished to sail up the Zwin to Bruges and land his army to support his hard-pressed allies. When the English were sighted the French manoeuvred to bar Edward's way to the port of Sluys. Their fleet organised itself in three lines, one behind the other, each stretching across the estuary of the Zwin. The ships of each line were bound together with chains and ropes to prevent the passage of enemy ships, "like a line of castles". Several large ships were stationed in the front of the line, including the very large captured English prize the "Christopher". This was a normal medieval tactic for a fleet fighting on the defensive. Barbavera, the experienced commander of the galleys, was concerned about this, realising they would lack manoeuvrability in their anchorage and be open to attack from the ship-based English archers. He advised the French commanders to put to sea and gain the weather gage, so as to be able to attack the English while they were disembarking, or deter this by the threat of an attack. Béhuchet, who as constable exercised overall command, knew little of naval operations. He viewed Barbavera as a mere commoner and near pirate, and wishing to take no chances of the English slipping past, insisted on holding a position blocking the inlet.