Editing Yacht (section)

== Motor yachts ==
[[File:80 foot motor yacht Alchemist photo D Ramey Logan.jpg|thumb|Lazzara {{convert|80|ft|m|adj=on}} planing-hull,  {{em|sports-cruiser}} motor yacht in 2014]]
[[File:Nordhavn 47d.jpg|thumb|''Nordhavn'' {{convert|47|ft|m|adj=on}} displacement-hull, {{em|expedition-style}} motor yacht in 2005]]
[[File:Therapy D81 9848 (29134390348).jpg|thumb|Grand Banks {{convert|42|ft|m|adj=on}} displacement-hull,  {{em|trawler-style}} motor yacht in 2018]]
Motor yachts range in length from {{Convert|33-130|ft|m}} before they are considered ''super-yachts or mega-yachts'', which are {{Convert|40|m|ft|order=flip}} and longer.  They also vary by use, by style, and by hull type.  As of April 2020 a {{Convert|600|ft|m|abbr=|adj=on}} yacht, ''REV Ocean'', was under construction,<ref>{{Cite web|last=Kirsch|first=Noah|title=The Ultimate Quarantine: This Oil Billionaire Is Building The World's Largest Superyacht – And Claims It Will Help Save The Oceans|url=https://www.forbes.com/sites/noahkirsch/2020/04/26/the-ultimate-quarantine-this-oil-billionaire-is-building-the-worlds-largest-superyacht--and-claims-it-will-help-save-the-oceans/|access-date=2020-11-03|website=Forbes|language=en}}</ref> which when launched would replace the {{Convert|590|ft|m|abbr=|adj=on}} ''[[Azzam (2013 yacht)|Azzam]]'' as the longest superyacht.<ref name="boat" />  As superyachts have grown size, the distinction between a yacht and a ship (perhaps converted for personal use) has become unclear.   A proposed definition for calling a vessel a yacht rather than a ship would if it was constructed solely for personal use and has a combined occupancy of less than 100, including crew.

===Classification===
The [[United States Coast Guard]] classifies motorboats—any vessel less than {{Convert|65|ft|m}}, propelled by machinery—in four classes by length:<ref>{{Cite book|last=United States Coast Guard|url=https://books.google.com/books?id=9dNaAAAAYAAJ&q=classification|title=Official U.S. Coast Guard Recreational Boating Guide|date=1966|publisher=U.S. Government Printing Office|location=Washington, DC|pages=6|language=en}}</ref>

*Class A: motorboats less than {{Convert|16|ft|m}}
*Class 1: motorboats {{Convert|16-26|ft|m}}
*Class 2: motorboats {{Convert|26-40|ft|m}}
*Class 3: motorboats {{Convert|40-65|ft|m}}

===Style===
A motor yacht's style can both be functional and evoke an aesthetic—trending towards the modern or the traditional. Among the styles, mentioned in the literature, are:<ref name="powerboat">{{Cite book|last=Pike|first=Dag|url=https://books.google.com/books?id=33WxDwAAQBAJ&q=style|title=Powerboat Design and Performance: Expert insight into developments past and future|date=2019-10-31|publisher=Bloomsbury Publishing|isbn=978-1-4729-6539-4|language=en}}</ref>

* ''Cruiser'' – A [[Cabin cruiser|cruiser]] has a displacement hull for economical, long-distance passage-making.
* ''Sports cruiser'' – A sports cruiser has a semi-displacement or planing hull for fast trips.
* ''Sports fisherman'' – A sports fisherman has a semi-displacement or planing hull for fast trips and carries gear for recreational catching of large fish.
* ''Expedition'' – An expedition yacht has a displacement hull for economical, long-distance passage-making to remote destinations. These are also called  {{em|explorer}} yachts.<ref name="explorer" />
* ''Lobster'' – A lobster yacht is styled like a Maine lobster boat and has a semi-displacement or planing hull for fast trips.
* ''Trawler'' – A trawler has conservative, traditional styling and has a displacement hull for economical, medium-distance passage-making.

===Hulls===
There are three basic types of motor yacht hull: {{em|full-displacement}}, {{em|semi-displacement}}, and {{em|planing}}, which have progressively higher cruise speeds and hourly fuel consumption with increased engine power:<ref name="powerandmotoryacht.com">{{cite news|url=http://www.powerandmotoryacht.com/design/understanding-hull-design|title=Understanding Hull Design|last=Thiel|first=Richard|date=May 2013|website=Power & Motoryacht|access-date=2020-04-23}}</ref>

* ''Full-displacement hulls'' move the water up and out of the way of the vessel, making a wave. They are limited in speed by the square root of the waterline length multiplied by a factor, depending on the units used. Added horsepower cannot increase the maximum speed, only the size of the waves produced. 
* ''Semi-displacement hulls'' allow speeds that are faster than the [[hull speed]] of a displacement vessel because they rise somewhat out of the water and create smaller waves. They also provide greater comfort than planing hulls.
* ''Planing hulls'' require sufficient power for the boat to slide up onto the surface, which avoids the need to use power to lift water out of the way of the vessel. Such vessels have flat surfaces on the undersides.

A typical semi-displacement yacht has a wedge-shaped bow, which promotes penetrating waves, that transitions to flatter, wider surfaces aft, which promotes lifting the vessel out of the water—the "deep vee" hull, designed by Ray Hunt, found in approximately 75% of modern power boats.<ref>{{Cite news|url=https://www.powerandmotoryacht.com/boat-design/the-basics-of-hull-design-explained|title=The Basics of Hull Design Explained|last=Prince|first=Bill|date=June 2019|website=Power & Motoryacht|language=en-us|access-date=2020-04-23}}</ref>

Cruising motor yachts are available in a range of styles as two-engine {{em|catamarans}}, ranging in length from {{Convert|40-150|ft|m}} with top speeds ranging from {{Convert|20-60|kn|km/h}}.<ref>{{Cite web|url=https://uk.boats.com/reviews/best-multihull-powerboats/|title=Best multihull powerboats - boats.com|last=Smith|first=Alex|date=February 12, 2018|website=Boats.com|access-date=2020-04-24}}</ref>

===Engines===
[[File:Yanmar.jpg|thumb|{{convert|260|hp|kW|adj=on}} diesel [[Inboard motor|marine engine]]]]
Motor yachts typically have one or more [[diesel engine]]s. Gasoline-powered motors and engines are the provenance of [[outboard motor]]s and [[Boat racing|racing boats]], due to their [[power-to-weight ratio]]s.<ref name="powerboat" /> Two engines add expense, but provide reliability and maneuverability over a single engine.<ref>{{Cite book|url=https://books.google.com/books?id=MdlLv77FCBYC&q=choosing+inboard+boat+engines&pg=RA17-PA16|title=Inboard Boats|date=February 1960|publisher=Boating Magazine|volume=7|language=en|issue=2}}</ref>

Motor yachts in the {{Convert|42|ft|m|adj=on}} range might have the following hull, horsepower, cruise speed, and hourly fuel consumption characteristics:

*{{em|Full-displacement hull}} – two {{Convert|135|hp|kW|adj=on}} diesels to cruise at {{Convert|9|kn|km/h}}, consuming {{Convert|5|gal/h|l/h}}.<ref name="grandbanks42">{{Cite web|url=https://www.boats.com/reviews/used-boat-review-grand-banks-42/|title=Grand Banks 42: Used Boat Review - boats.com|last=Knauth|first=Steve|date=March 29, 2010|website=Boats.com|access-date=2020-04-24}}</ref> 
* {{em|Semi-displacement hull}} – two {{Convert|350|hp|kW|adj=on}} diesels to cruise at {{Convert|17|kn|km/h}}, consuming {{Convert|45|l/h|gal/h|order=flip}}.<ref>{{Cite web|url=https://www.azimutyachts.com/azimutmagellano43.html|title=Technical characteristics: Azimut Magellano 43|last=Azimut Yachts|website=www.azimutyachts.com|access-date=2020-04-24}}</ref><ref>{{Cite web|url=https://www.canadianyachting.ca/boat-reviews/power/2641-azimut-magellano-43|title=Azimut Magellano 43|last=Elissa|website=www.canadianyachting.ca|language=en-gb|access-date=2020-04-24}}</ref> 
*{{em|Planing hull}} – two {{Convert|400|hp|kW|adj=on}} diesels to cruise at {{Convert|30|kn|km/h}}, consuming {{Convert|90|l/h|gal/h|order=flip}}.<ref>{{Cite web|url=https://www.azimutyachts.com/azimutatlantis43.html|title=Technical characteristics: Azimut Atlantis 43|last=Azimut Yachts|website=www.azimutyachts.com|access-date=2020-04-24}}</ref><ref name="grandbanks42" />

Superyachts may employ multiple {{Convert|9000|hp|kW|adj=on}} diesels<ref>{{cite web|url=https://www.superyachttimes.com/yachts/fulk-al-salamah|title=Exclusive: Mariotti superyacht Fulk Al Salamah delivered|publisher=SuperYacht Times}}</ref> or a combination of diesels and [[gas turbine]]s with a combined {{Convert|47,000|hp|kW}}.<ref name="SYTimes-NautaComments">{{cite news|url=http://www.superyachttimes.com/editorial/17/article/id/10346|title=Nauta Yachts comments on their design for superyacht Azzam|date=9 April 2013|work=SuperYacht Times|access-date=10 April 2013}}</ref>