A typical modern super yacht tries to maximise accommodation within a given length, this leads to high beam and high, long, superstructures. It also makes for heavy and hydrodynamically not very efficient vessels operating at high speed length ratios and requiring high power to achieve this. Length is of course a driver of cost, but more importantly so is the outfit volume and weight and the relationship between Gross Tonnage (GT) and cost is used by most yards when quoting. Naval Architects have long known that for a given speed the longer, leaner and lighter the vessel the better in terms of performance and efficiency, but the super yacht market largely ignores this.
Laurent Giles have been developing this design concept for a High Efficiency Motor Yacht hull (HEMY) which embodies these principles to offer far higher maximum and cruising speeds for roughly the same power as a typical 70 m yacht. The low hydrodynamic drag of the hull form is enhanced by low simple superstructures to reduce windage drag and an advanced hybrid diesel electric propulsion system. The low, aerodynamically efficient superstructure helps to keep the centre of gravity low, which means the hull has good form stability despite its slender beam of 12.5m