A hull is the watertight body of a ship, boat, or flying boat. The hull may open at the top, or it may be fully or partially covered with a deck. Atop the deck may be a deckhouse and other superstructures, such as a funnel, derrick, or mast. The line where the hull meets the water surface is called the waterline.
A waveplate or retarder is an optical device that alters the polarization state of a light wave travelling through it. Two common types of waveplates are the half-wave plate, which shifts the polarization direction of linearly polarized light, and the quarter-wave plate, which converts linearly polarized light into circularly polarized light and vice versa. A quarter-wave plate can be used to produce elliptical polarization as well.
An icebreaker is a special-purpose ship or boat designed to move and navigate through ice-covered waters, and provide safe waterways for other boats and ships. Although the term usually refers to ice-breaking ships, it may also refer to smaller vessels, such as the icebreaking boats that were once used on the canals of the United Kingdom.
Boat building is the design and construction of boats and their systems. This includes at a minimum a hull, with propulsion, mechanical, navigation, safety and other systems as a craft requires.
In the Star Trek franchise, the Klingon Empire makes use of several classes of starships. As the Klingons are portrayed as a warrior culture, driven by the pursuit of honor and glory, the Empire is shown to use warships almost exclusively and even their support ships, such as troop transports and colony ships, are armed for battle. This contrasts with the exploration and research vessels used by Starfleet, the protagonists of the franchise. The first Klingon ship design used in The Original Series, the D7-class battlecruiser, was designed by Matt Jefferies to evoke a shape akin to that of a manta ray, providing a threatening and instantly recognizable form for viewers. The configuration of Jefferies's design featured a bulbous forward hull connected by a long boom to a wing-like main hull with the engine nacelles mounted on each wingtip. Though a variety of Klingon ships have appeared in Star Trek, their design generally conforms to this style. Most Klingon vessels were physically built as scale models, although later computer-generated imagery was used to create the models. In recent years, many of the original studio models have been sold at auctions.
A ship model basin is a basin or tank used to carry out hydrodynamic tests with ship models, for the purpose of designing a new ship, or refining the design of a ship to improve the ship's performance at sea. It can also refer to the organization that owns and operates such a facility.
Hull speed or displacement speed is the speed at which the wavelength of a vessel's bow wave is equal to the waterline length of the vessel. As boat speed increases from rest, the wavelength of the bow wave increases, and usually its crest-to-trough dimension (height) increases as well. When hull speed is exceeded, a vessel in displacement mode will appear to be climbing up the back of its bow wave.
A bulbous bow is a protruding bulb at the bow of a ship just below the waterline. The bulb modifies the way the water flows around the hull, reducing drag and thus increasing speed, range, fuel efficiency, and stability. Large ships with bulbous bows generally have twelve to fifteen percent better fuel efficiency than similar vessels without them. A bulbous bow also increases the buoyancy of the forward part and hence reduces the pitching of the ship to a small degree.
The bow is the forward part of the hull of a ship or boat, the point that is usually most forward when the vessel is underway. The aft end of the boat is the stern.
Bevel gears are gears where the axes of the two shafts intersect and the tooth-bearing faces of the gears themselves are conically shaped. Bevel gears are most often mounted on shafts that are 90 degrees apart, but can be designed to work at other angles as well. The pitch surface of bevel gears is a cone, known as a pitch cone. Bevel gears transfer the energy from linear to vertical power, making it very useful in machines widely used in mechanical settings.
A wave-piercing boat hull has a very fine bow, with reduced buoyancy in the forward portions. When a wave is encountered, the lack of buoyancy means the hull pierces through the water rather than riding over the top, resulting in a smoother ride than traditional designs, and in diminished mechanical stress on the vessel. It also reduces a boat's wave-making resistance.
Wave-making resistance is a form of drag that affects surface watercraft, such as boats and ships, and reflects the energy required to push the water out of the way of the hull. This energy goes into creating the wave.
A Schilling rudder is a specific type of profiled rudder used on certain boats and ships.
Seakeeping ability or seaworthiness is a measure of how well-suited a watercraft is to conditions when underway. A ship or boat which has good seakeeping ability is said to be very seaworthy and is able to operate effectively even in high sea states.
In ship design, an inverted bow is a ship's or large boat's bow whose farthest forward point is not at the top. The result may somewhat resemble a submarine's bow. Inverted bows maximize the length of waterline and hence the hull speed, and have often better hydrodynamic drag than ordinary bows. On the other hand, they have very little reserve buoyancy and tend to dive under waves instead of piercing or going over them.
The Guardiao is the Cape Verde Coast Guard's first patrol vessel based on the Damen Stan 5009 design.
In radio systems, many different antenna types are used whose properties are especially crafted for particular applications. Antennas can be classified in various ways. The list below groups together antennas under common operating principles, following the way antennas are classified in many engineering textbooks.
JS Chihaya (ASR-403) is a submarine rescue ship of Japan Maritime Self-Defense Force.
The Warrior-class inshore patrol vessel is a class of multi-mission inshore patrol vessels (MMIPVs) built for the South African Navy, and are intended to replace the Warrior-class OPVs between 2022 and 2024. All three vessels are named after historical South African 'warriors' who had a significant impact on the development of the country.
XV Patrick Blackett (X01) is an experimental ship used by the Royal Navy as a testbed for new technologies, including unmanned underwater vehicles and unmanned surface vehicles. Her namesake is Patrick Blackett, a Royal Navy veteran and Nobel Prize-winning British physicist.
