M5 is a sloop-rigged super yacht launched in 2003 as Mirabella V. She is the largest single-masted yacht ever built. Ownership Mirabella V was built as part of a fleet of large sailing yachts used for luxury private charters by Joseph Vittoria, former Chairman and CEO of the Avis car rental company. She was named after Vittoria's previous yachts. Mirabella V now belongs to Rodney Lewis and has been renamed M5. It is no longer available for charters. Design The owner specifications combined fast sailing with motoryacht amenities. The righting moment of sailing vessels makes them more seakindly than powerboats and M5 has achieved speeds in excess of 19 knots in 8 1/2 ft seas. To achieve the amenity requirements, a single mast was preferred to other rig types in order to maximize interior volumes in keel-stepped sailing yachts; To achieve the performance requirements, the higher aspect ratio of the single mast sail plan was also preferred in order to provide a better speed potential. A final demand was that the yacht be able to use the harbour at Palm Beach, Florida. This required the use of a lifting keel to reduce draft. Mirabella V was designed by yacht designer Ron Holland. Load and structural calculations of the hull and rig were carried out by Hamble-based firm High Modulus Europe Ltd, (now part of Gurit). Technical challenges While vessels of M5s size are typically made from steel or aluminium, an aramid foam core/vinylester sandwich build was chosen to achieve a shorter delivery date, reduced maintenance (regular repainting to inhibit corrosion is not required) and better acoustic thermal insulation. Historically, large yachts were built with more than one mast in order to divide the sail area for easier handling. Today's technologies in spars, rigging, sailmaking, powered winches and electronics enable rigs with larger sail areas, higher aspect ratios, larger loads and simpler handling, allowing Mirabella V to be constructed with the tallest mast and largest jib of any sailing craft ever built at the time. One of the procurement challenges was finding sheets strong enough to trim the sails. Construction Mirabella V was constructed at the former BVT Surface Fleet yard (formerly VT Shipbuilding formerly Vosper Thornycroft) at its Woolston Yard, Southampton, Hampshire. Luciana Vittoria specified to naval architect Ron Holland her wishes for interior decoration. After changing hands and being rechristened M5, she was handed over for refit to the