The Tyrrhenian coastline between Sorrento and Salerno curves through fifty kilometres of vertical limestone, a sequence of thirteen municipalities clinging to cliffs that drop two hundred metres into water the Romans called mare nostrum. The Amalfi Coast earned UNESCO World Heritage designation in 1997 for its Mediterranean landscape and terraced lemon groves, but the designation omitted the coast's defining characteristic: it is best understood from the sea. Land roads, carved into the rock face in the nineteenth century, twist through tunnels and hairpin bends; the water route, used for millennia by fishing fleets and merchant galleys, remains the most direct. Private boat charters operate from five principal ports — Positano, Amalfi, Atrani, Maiori, and Sorrento — with vessels ranging from traditional gozzo wooden boats to modern speedboats. The gozzo, a double-ended fishing craft with a wide beam, was designed in the 1920s for stability in the Gulf of Naples and remains the preferred vessel for coastal touring. Most charters depart between 08:00 and 20:00, though morning slots between 09:00 and 11:00 offer calmer seas and softer light before the midday sun heats the limestone to forty degrees Celsius in summer months. The maritime route passes the Fiordo di Furore, a narrow fjord cutting inland beneath a stone bridge, and the Li Galli archipelago, three islets once owned by dancer Rudolf Nureyev. Captains navigate into the Grotta dello Smeraldo near Conca dei Marini, where submerged sunlight refracts through seawater to produce an emerald luminescence, and the smaller sea caves accessible only by dinghy. Positano's vertical cascade of pastel houses, built by Saracen refugees in the ninth century, presents its most coherent silhouette when viewed from two hundred metres offshore. The coastline's architecture — domed churches, Moorish arches, majolica-tiled cupolas — developed under the Republic of Amalfi, a maritime power that rivaled Venice and Genoa before Norman conquest in 1131. Amalfi Coast private boat tours typically include mooring time at secluded beaches unreachable by road, swimming stops in coves near Praiano, and deck service of prosecco or limoncello produced from sfusato lemons grown on the terraces above. Charters range from two-hour express routes to full-day itineraries covering Capri and the Sorrento Peninsula, with departure points chosen based on wind patterns and swell direction that shift between the gulf's eastern and western shores.