The focus of the war shifted to the sea, where the Romans had little experience; on the few occasions they had previously felt the need for a naval presence they relied on small squadrons provided by their allies. In 260 BC Romans set out to construct a fleet using a shipwrecked Carthaginian quinquereme as a blueprint for their own ships. Frustration at the continuing stalemate in the land war on Sicily, combined with naval victories at Mylae (260 BC) and Sulci (258 BC), led the Romans to develop a plan to invade the Carthaginian heartland in North Africa and threaten their capital (close to what is now Tunis). Both sides were determined to establish naval supremacy and invested large amounts of money and manpower in maintaining and increasing the size of their navies.