A catamaran's twin hulls slice the Adriatic at half the draft of a monohull, letting skippers nose into sea caves and anchor over shallow reefs that conventional charter boats cannot reach. The advantage matters most along Dubrovnik's archipelago coast, where karst geology carved a hundred grottoes below the waterline and deposited pale sand in coves that remain inaccessible by road. Operators running dubrovnik boat tours catamaran itineraries depart Gruž Port each morning between eight and nine, motoring past the Lokrum cliffs before raising sail in open water. The Elaphite Islands — Koločep, Lopud, Šipan — form the backbone of most routes. Koločep's Blue Cave sits at sea level in a limestone overhang; sunlight refracts through the entrance and tints the interior walls cyan between ten and noon. Lopud's Šunj Beach lies on the island's southern shore, a crescent of fine shale backed by pine forest and fed by a shallow gradient that warms quickly under summer sun. Šipan, the largest of the three, produces olive oil from trees planted during the Ragusan Republic and shelters a deepwater bay where catamarans moor for lunch service. The standard itinerary includes two swimming stops, one snorkeling interval over eel grass beds, and a midday meal served on deck or ashore depending on wind. Catamaran design favors stability over speed. The wide beam and low center of gravity reduce heel, making the deck safer for passengers unfamiliar with sailing and allowing operators to serve food and pour wine under way without the tilt of a keelboat. Most vessels in the Dubrovnik charter fleet measure twelve to fifteen meters, carry fifteen to thirty passengers, and feature a shaded cockpit, a foredeck sunbathing net strung between the hulls, and a swim platform aft. Rigging varies: some boats sail only when wind exceeds ten knots, others motor the entire route and use the mast for shade. The twin engines allow precise maneuvering in tight anchorages, and the shallow draft means skippers can tuck into coves where the anchor settles in three meters of water over sand and rock. Seven sea caves punctuate the coast between Cavtat and the Elaphite chain. Blue Cave draws the most traffic, but Green Cave on the western side of Koločep and a nameless grotto near Daksa Island offer similar light effects with fewer boats queued at the entrance. Most dubrovnik boat tours catamaran routes visit one or two caves depending on swell and schedule. Operators provide snorkeling gear, and visibility frequently exceeds fifteen meters over the reefs where damselfish and wrasse shelter in the urchin beds. Departure times cluster in the morning to avoid the afternoon maestral wind, which builds from the northwest and raises chop across the channel by mid-afternoon.