Definition courtesy of wikipedia
The term luxury yacht, “Superyacht” and "Large Yacht" refers to very expensive, privately owned yachts which are professionally crewed. Also known as a Super Yacht, a luxury yacht may be either a sailing or motor yacht.
This term began to appear at the beginning of the 20th century when wealthy individuals constructed large private yachts for personal pleasure. This coincided with it being picked up by the press as well, and its appearance in magazines such as Boat International, cemented it as an every day term in the industry. Examples of early luxury motor yachts include the Cox & King yachts, M/Y (motor yacht) Christina O and M/Y Savarona. Early luxury sailing yachts include Americas Cup classic J class racers like S/Y (sailing yacht) Endeavour and Sir Thomas Lipton's S/Y Shamrock. The New York Yacht Club hosted many early luxury sailing yacht events at Newport, Rhode Island, during the Gilded Age.
Between 1997 and 2008 there was a massive growth in the number, size, and popularity of large private or Super luxury yachts. This was in the 24 to 70 meter size range. Luxury, Large or Super yachts typically have no real home port as such although a yacht must be registered in a port of the country to which flag state it is registered in. Popular flag state registrars for large yachts are Cayman Islands, Marshall Islands, Isle of Man, British Virgin Islands among others. (Many times the yacht will have never been to these ports.) They are particularly bountiful in the Mediterranean in summer and the Caribbean Sea in winter. Many can be chartered (rented) for sums of up to 1 million Euro for a week. There may be up to 1500 Large yachts available to Charter in a season in the Mediterranean. (Yachts that go back and forth between the Caribbean and Mediterranean in the winter and summer are said to be doing the Milk Run.) The arrival of large commercial ships that have been specially outfitted to take multiple Large yachts across the Atlantic ocean have created a much larger Charter market in the Caribbean than ever before. Yachts will dock in a port of choosing while the crew does maintenance work and waits for owners or guests to arrive. The vessels then will do short cruises with the owners and/or guests aboard. Typical destinations in Spain and the French and Italian Rivieras include Cannes, Antibes, St. Tropez, Monte Carlo, Portofino, Porto Cervo, Puerto Banus, Puerto Portals and Palma, Majorca, although increasingly luxury yachts are cruising in more remote areas of the world. Antigua is one of the main ports in the Windward Islands of the Caribbean and hosts a Charter Show at the beginning of the winter season.
While the demand for new luxury yachts has slowed somewhat since 2009, 2011 has seen a small rebound with launches from many of the top yards. The latest launch, M/Y Eclipse, built by Blohm + Voss for Russian businessman Roman Abramovich is the largest yacht in the world. Luxury boat building and yacht charter companies are predominantly based in the United States and Western Europe but are also increasingly found in New Zealand, Asia and Eastern Europe.
Some yachts are used exclusively by their private owners, others are operated all year round as charter businesses, and a large number are privately owned but available for charter part time. The weekly charter rate of luxury yachts around the world ranges from a high of €661,500 (M/Y Annaliesse) to around €20,000. Expenses of approximately 25-30%, such as food, fuel, and berthage are charged as an extra as well as a customary 15-20% crew gratuity for good service. The luxury yacht charter industry functions effectively because private yacht owners mitigate their running costs with charter income as well as keeping their yachts and crew in top running order. Conversely, private charterers charter yachts (rather than owning them) because it is generally considered to be less expensive, and less hassle, than owning a yacht and it also provides them with extra choice related to yacht type, location and crew. One super yacht that is frequently followed is the 77m Samar built by Devonport in 2006 and owned by the reclusive entrepreneur Jeff Coxon. She carries 20 crew and can accommodate 14 guests.
Yachts from 24 metres (79 ft) and up qualify for design awards, but at the bottom end of that scale yachts will not necessarily be crewed and many set the minimum length for a superyacht considerably higher. A 45-to-50-metre (148 to 160 ft) yacht, the smallest with a generally accepted claim to superyacht status, will usually be a three-decker with cabins for 10-12 guests (that is a preferred number, more common than 14, and is found on yachts across quite a wide size range), and for a crew of a similar size. The accommodation on this type of yacht is typically as follows:
- Lower deck: exterior swimming platform at the stern; four (sometimes five) guest cabins with en-suite bath or shower rooms aft; engine room amidships; crew quarters forward.
- Main deck: sheltered exterior deck aft leading into the salon; dining room and galley; entrance amidships; owner's suite forward, usually includes either a study or a second twin stateroom.
- Upper deck: exterior deck aft, often used for outdoor dining; second salon (often called the sky lounge); staffed bar inside or outside or both; sixth stateroom will be amidships if it is not on the lower deck or part of the owner's suite; gym (may also be on the lower deck or part of the owner's suite); captain's cabin; bridge.
- Sun deck: on the roof of the upper deck, often features a jacuzzi.
A 50 metre yacht will have one or more luxury yacht tenders for reaching shore and other "toys" which may include a speed boat or sailing boat, personal water craft, windsurfing and diving equipment and a Banana boat. Up to date yachts have multiple flat screen televisions and satellite communications.
The number of very large yachts has increased rapidly since the 1990s and increasingly only yachts above around 65 metres (213 ft) stand out among other luxury yachts. Yachts of this size are almost always built to individual commissions and cost tens of millions of dollars (most super-yachts cost far more than their owners' homes on land, even though those homes are likely to be among the largest and most desirable). A yacht of this size usually has four decks above the water line and one or two below. It is likely to have a helicopter landing platform. Apart from additional guest cabins, which are likely to include one or more "VIP suites" besides the owner's suite, extra facilities compared to a 50-metre (160 ft) yacht will include some or all of indoor jacuzzis, sauna and steam rooms, a beauty salon, massage and other treatment rooms, a medical centre, a discothèque, a cinema with a film library, plunge pool (possibly with a wave-maker), a playroom, and additional living areas such as a separate bar, secondary dining room, private sitting rooms or a library. There will be more boats and "toys" than there are on a 50-metre (160 ft).
Mega yacht Lady Moura in Monaco harborGiga yachts or Mega yachts are vessels over 100m in length. As of 2012 yachts above 100 metres (328 feet) are still rare but increasingly more common, with an estimated 24 on the water  They typically have five decks above the water line and one below. The very largest yachts have begun to incorporate such features as helicopter hangars, indoor swimming pools and miniature submarines. The burgeoning number of "small" super yachts has led to the introduction of the hyperbolic terms "Mega Yacht" and "Giga Yacht" to demarcate the elite among luxury yachts.
The crew required to operate a large or super luxury yacht can number from 8 members for a 120 ft yacht, to a complement of 70 for a yacht the size of Eclipse. The crew is made up of a Captain, Chief Engineer, Engineer/s, First Mate, Officer, Bosun, Chef/s, Crew Chef, Deckhand/s and Stewardess/Steward/s. Luxury yachts are maintained by crew all year round but will often scale down to a skeleton crew during the seasons that the owners are not on board and no charters are booked. Most crew members live on board and are paid a monthly salary, with most living expenses covered by the owner. Live on board crews do not pay rent, food, electricity or water bills. All luxury yachts have crew areas below deck, which consist of a crew mess, crew cabins and laundry. Most crew cabins have bunk beds, however, there are Captains and Chief Engineers who, on the larger yachts, have their own cabins. There are no set hours that crew members work each week. The hours depend greatly on how often the owners are on board, how often it is chartered and on what hours the Captain sets when there are no guests on board.