The ships to transport the English army had finally gathered in Portsmouth in early August and the Earl of Northampton left port with just 1,350 men in 260 small coastal transports, some conscripted from as far away as Yarmouth for this duty. Just three days after leaving Portsmouth, Northampton's force arrived off Brest. The English fleet closed on the Genoese in the entrance to the Penfeld River where they were anchored in a vertical line. The Genoese panicked, three of the fourteen galleys fled from the crowd of diminutive opponents which were struggling to board the larger Genoese ships and reached the safety of the Elorn River estuary from where they could escape into the open sea. The remaining eleven were surrounded and drove ashore battling their opponents, where the crews abandoned them to the boarders and fired them as they left, at a stroke destroying French naval supremacy in Breton waters. Believing that the ships carried a prodigious English force of trained warriors, Charles broke the siege and made for Northern Brittany with the remaining Genoese whilst a substantial part of his army made up of Castilian and Genoese mercenary infantry retreated to Bourgneuf and took their ships back to Spain.