Editing Ship (section)

==Architecture==
{{Further|Naval architecture}}
Some components exist in vessels of any size and purpose. Every vessel has a hull of sorts. Every vessel has some sort of propulsion, whether it's a pole, an ox, or a nuclear reactor. Most vessels have some sort of steering system. Other characteristics are common, but not as universal, such as compartments, holds, a superstructure, and equipment such as anchors and winches.

===Hull===
{{main|Hull (watercraft)}}
[[File:CargoVslBadWeather.JPG|thumb|right|A ship's hull endures harsh conditions at sea, as illustrated by this [[reefer ship]] in bad weather.]]
For a ship to float, its weight must be less than that of the water displaced by the ship's hull.<ref>{{cite web|title=Boats – Why do they float?|url=https://betterplaneteducation.org.uk/factsheets/boats-how-boats-float|publisher=Better Planet Education (formerly YPTE) |access-date=16 September 2024 |url-status=live |archive-url=https://web.archive.org/web/20121231065913/http://www.ypte.org.uk/environmental/boats-why-do-they-float-/107 |archive-date= Dec 31, 2012 }}</ref> There are many types of hulls, from logs lashed together to form a raft to the advanced hulls of [[America's Cup]] sailboats. A vessel may have a single hull (called a monohull design), two in the case of [[catamaran]]s, or three in the case of [[trimaran]]s. Vessels with more than three hulls are rare, but some experiments have been conducted with designs such as pentamarans. Multiple hulls are generally parallel to each other and connected by rigid arms.

Hulls have several elements. The [[bow (ship)|bow]] is the foremost part of the hull. Many ships feature a [[bulbous bow]]. The [[keel]] is at the very bottom of the hull, extending the entire length of the ship. The rear part of the hull is known as the [[stern]], and many hulls have a flat back known as a [[transom (nautical)|transom]]. Common hull appendages include [[propeller]]s for propulsion, [[rudder]]s for steering, and [[Stabilizer (ship)|stabilizers]] to quell a ship's rolling motion. Other hull features can be related to the vessel's work, such as fishing gear and [[sonar|sonar domes]].

Hulls are subject to various hydrostatic and hydrodynamic constraints. The key hydrostatic constraint is that it must be able to support the entire weight of the boat, and maintain stability even with often unevenly distributed weight. Hydrodynamic constraints include the ability to withstand shock waves, weather collisions and groundings.

Older ships and pleasure craft often have or had wooden hulls. Steel is used for most commercial vessels. Aluminium is frequently used for fast vessels, and [[composite material]]s are often found in sailboats and pleasure craft. Some ships have been made with [[Concrete ship|concrete hulls]].

===Propulsion systems===
{{Main|Marine propulsion}}
[[File:Two Main Engines, V12.jpg|thumb|right|A ship's engine room]]
Propulsion systems for ships fall into three categories: human propulsion, [[sailing]], and mechanical propulsion. Human propulsion includes [[Watercraft rowing|rowing]], which was used even on large [[galley]]s. Propulsion by sail generally consists of a sail hoisted on an erect mast, supported by stays and spars and controlled by ropes. Sail systems were the dominant form of propulsion until the 19th century. They are now generally used for recreation and competition, although experimental sail systems, such as the [[turbosail]]s, [[rotorsail]]s, and [[wingsail]]s have been used on larger modern vessels for fuel savings.

Mechanical [[propulsion systems]] generally consist of a motor or engine turning a [[propeller]], or less frequently, an [[impeller]] or [[wave power ship|wave propulsion fins]]. [[Steam engine]]s were first used for this purpose, but have mostly been replaced by [[two-stroke engine|two-stroke]] or [[four-stroke engine|four-stroke]] diesel engines, outboard motors, and [[gas turbine engine]]s on faster ships. [[Nuclear marine propulsion|Nuclear reactors]] producing steam are used to propel [[warship]]s and [[icebreaker]]s, and there have been attempts to use them to power commercial vessels (see [[NS Savannah|NS ''Savannah'']]).

In addition to traditional fixed and controllable pitch propellers there are many specialized variations, such as contra-rotating and nozzle-style propellers. Most vessels have a single propeller, but some large vessels may have up to four propellers supplemented with [[bow thruster|transverse thrusters]] for maneuvring at ports. The propeller is connected to the main engine via a propeller shaft and, in case of medium- and high-speed engines, a reduction gearbox. Some modern vessels have a [[diesel–electric powertrain]] in which the propeller is turned by an [[electric motor]] powered by the ship's generators.

As environmental sustainability becomes a paramount concern, the maritime industry is exploring cleaner propulsion technologies. Alternatives like LPG (Liquefied Petroleum Gas), ammonia, and hydrogen are emerging as viable options. LPG is already utilized as fuel for long-distance shipping,<ref>{{Cite web |title=LPG Propulsion Explained |url=https://www.bwlpg.com/vlgc_fleet/lpg-propulsion/lpg-propulsion-explained/ |access-date=2024-04-04 |website=BW LPG |language=en-US}}</ref> offering a cleaner option with a lower carbon footprint. Meanwhile, hydrogen and ammonia technologies are in development stages for long-haul applications, promising even more significant reductions in emissions and a step closer to achieving [[Decarbonization of shipping|carbon-neutral shipping.]]

=== Steering systems ===
[[File:Ferry-rudder-and-propeller.jpg|thumb|right|The rudder and propeller on a newly built [[Ferryboat|ferry]]]]

For ships with independent propulsion systems for each side, such as manual oars or some [[paddle steamer|paddles]],{{efn|Almost all paddle steamers had a single engine with their paddles permanently coupled, without any clutches, and so could not be used for steering. Only a few examples with separate engines were steerable. For example, the [[Royal Navy]] operated diesel–electric harbour tugs with paddles into the 1970s for their superior manoeuvrability.}} steering systems may not be necessary. In most designs, such as boats propelled by engines or sails, a steering system becomes necessary. The most common is a rudder, a submerged plane located at the rear of the hull. Rudders are rotated to generate a lateral force which turns the boat. Rudders can be rotated by a [[tiller]], manual wheels, or electro-hydraulic systems. [[Autopilot]] systems combine mechanical rudders with navigation systems. [[Ducted propeller]]s are sometimes used for steering.

Some propulsion systems are inherently steering systems. Examples include the [[outboard motor]], the [[bow thruster]], and the [[azimuth thruster]].

===Holds, compartments, and the superstructure===
Larger boats and ships generally have multiple decks and compartments. Separate [[berthing]]s and [[Head (watercraft)|heads]] are found on sailboats over about {{convert|25|ft|m}}. Fishing boats and cargo ships typically have one or more cargo holds. Most larger vessels have an engine room, a [[galley (kitchen)|galley]], and various compartments for work. Tanks are used to store fuel, engine oil, and fresh water. Ballast tanks are equipped to change a ship's trim and modify its stability.

Superstructures are found above the main deck. On sailboats, these are usually very low. On modern cargo ships, they are almost always located near the ship's stern. On passenger ships and warships, the superstructure generally extends far forward.

===Equipment===
Shipboard equipment varies from ship to ship depending on such factors as the ship's era, design, area of operation, and purpose. Some types of equipment that are widely found include:{{Citation needed|date=March 2021}}
* [[Mast (sail)|Masts]] can be the home of antennas, navigation lights, radar transponders, fog signals, and similar devices often required by law.
* Ground tackle comprises the anchor, its chain or cable, and connecting fittings.<ref>{{Cite web|title=Ground tackle definition |url=https://www.collinsdictionary.com/us/dictionary/english/ground-tackle|access-date=2021-03-06|website=Collins English Dictionary |language=en-US |url-status=live |archive-url=https://archive.today/20240112043819/https://www.collinsdictionary.com/us/dictionary/english/ground-tackle |archive-date= 12 January 2024 }}</ref>
* Cargo equipment such as [[Crane (machine)|cranes]] and cargo booms may be used to load and unload cargo and ship's stores.
* Safety equipment such as [[Lifeboat (shipboard)|lifeboats]], [[liferaft]]s, and [[survival suit]]s are carried aboard many vessels for emergency use.