Superyacht characteristics: A superyacht is a luxury yacht that is professionally crewed and is over 79 feet long. Some superyachts are either used exclusively by their owners or are available part time for commercial charter, while others are operated all year round as charter businesses.
Features often include a swimming platform, three to six guest cabins with en-suite baths, engine room, crew quarters, dining room and galley, owner's suite, usually including a study, outdoor dining area, sky lounge, bridge, sun deck with a jacuzzi and gym. Many come equipped with tenders for reaching shore and other "toys," which may include fishing boats, personal watercraft, windsurfing and diving equipment, paddleboards, kayaks, canoes and other water toys.
The burgeoning number of “small” superyachts has led to the introduction of the hyperbolic terms like megayacht and gigayacht to demarcate the elite (300 feet+) among luxury yachts. A significant number of yachts are now over 3,000 gross tons.
Apart from additional guest cabins, which are likely to include one or more "VIP suites" besides the owner's suite, these larger superyachts may include features such as helicopter landing platform or hangar, a submersible, indoor jacuzzis, sauna and steam rooms, a beauty salon, massage and other treatment rooms, a dance area, a cinema, a plunge pool or a gym.
Superyacht construction and hull design: Most superyachts are constructed in Europe. Typical superyacht hull shapes are the displacement yacht hull, semi-displacement (semi-planing) hull and planing hull.
Displacement hulls are much more forgiving in terms of weight, where the impact on performance is minor. They have less initial stability, but more dynamic stability, which equals more comfort. They can carry more fuel, and use less, which equates to more range, and offer the most volume at common interior positions. Also, interior materials do not need to be lightweight.
Semi-displacement hulls are flatter and lighter and have a sharper forebody and higher initial stability. They offer less flexibility in weight and weight position and they have a wider speed range, so lower speeds mean lower engine loading, which is not optimal. There is an optimum size - going smaller and smaller makes a semi-planing hull harder to achieve, and going larger and larger means the weight increases disproportionately. They can be optimized for higher or lower speeds, but not both. Some believe they offer the best of both worlds with lots of possibilities.
In superyachts with planing hulls, the engine room forms a significant part of hull volume (up to 30-40 percent). A big beam and little weight mean extreme initial stability, and they may be uncomfortable in certain sea conditions. Friction is significant, so if left in the water for a couple of seasons the speed will drop. They offer the possibility of lots of exotic hull shapes, however, dynamic stability is a big factor and can limit what is possible. However, they have a speed benefit and can escape bad weather more easily.
Popular brands include Lurssen, Feadship, Oceanco, Christensen, Heesen, Amels, Royal Huisman, Blohm+Voss and Norbiskrug.
Superyacht power options: While superyachts can be motor or sail powered, the vast majority today are powered by diesel engines.
Diesel engines are popular largely in part to their versatility: they range from small ones like a Yanmar single-cylinder, 8 hp engine to some of the world’s largest, such as a Wartsila Sulzer propulsion engine of over 113,000 hp. Some diesel engines operate in excess of 4,000 rpm, while others run at less than 100 rpm. Many utilize a common-rail injector system that employs electronically controlled fuel injectors.