 | This article relies largely or entirely on a single source .(May 2022) |
Air cavity system (or ACS) is a modern marine hull design concept based upon capturing air beneath a vessel's hull to reduce drag and increase speed and fuel efficiency.
| | This article relies largely or entirely on a single source .(May 2022) |
Air cavity system (or ACS) is a modern marine hull design concept based upon capturing air beneath a vessel's hull to reduce drag and increase speed and fuel efficiency.
The system works by trapping a layer of air bubbles beneath the ship's hull. A dedicated system or an air blower generates air bubbles that pass nonstop under the ship's surface. Along the bottom of the hull, air bubble outlets are located at different sites equally on both the sides of the boat's center. A layer of bubbles is formed by blowing air at a constant rate, reducing the drag and resistance between the boat and the water. [1]
ACS is used on the Russian Serna- [2] and Dyugon-class landing crafts.
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 hydrofoil is a lifting surface, or foil, that operates in water. They are similar in appearance and purpose to aerofoils used by aeroplanes. Boats that use hydrofoil technology are also simply termed hydrofoils. As a hydrofoil craft gains speed, the hydrofoils lift the boat's hull out of the water, decreasing drag and allowing greater speeds.
The United States Navy, United States Coast Guard, and United States National Oceanic and Atmospheric Administration (NOAA) use a hull classification symbol to identify their ships by type and by individual ship within a type. The system is analogous to the pennant number system that the Royal Navy and other European and Commonwealth navies use.
Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the water, on ice (iceboat) or on land over a chosen course, which is often part of a larger plan of navigation.
Supercavitation is the use of a cavitation bubble to reduce skin friction drag on a submerged object and enable high speeds. Applications include torpedoes and propellers, but in theory, the technique could be extended to an entire underwater vessel.
A jetboat is a boat propelled by a jet of water ejected from the back of the craft. Unlike a powerboat or motorboat that uses an external propeller in the water below or behind the boat, a jetboat draws the water from under the boat through an intake and into a pump-jet inside the boat, before expelling it through a nozzle at the stern.
A catamaran is a multi-hulled watercraft featuring two parallel hulls of equal size. It is a geometry-stabilized craft, deriving its stability from its wide beam, rather than from a ballasted keel as with a monohull boat. Catamarans typically have less hull volume, smaller displacement, and shallower draft (draught) than monohulls of comparable length. The two hulls combined also often have a smaller hydrodynamic resistance than comparable monohulls, requiring less propulsive power from either sails or motors. The catamaran's wider stance on the water can reduce both heeling and wave-induced motion, as compared with a monohull, and can give reduced wakes.
ACS or Acs may refer to:
The Landing Craft Air Cushion (LCAC) is a class of air-cushioned landing craft (hovercraft) used by the United States Navy and the Japan Maritime Self-Defense Force (JMSDF). They transport weapons systems, equipment, cargo and personnel from ship to shore and across the beach. It is to be replaced in US service by the Ship-to-Shore Connector (SSC).
Skjold-class corvettes are a class of six light, superfast, stealth missile corvettes in service with the Royal Norwegian Navy. The boats were formerly classed as MTBs but, from 2009, the Royal Norwegian Navy has described them as corvettes (korvett) because their seaworthiness is seen as comparable to corvettes, and because they do not carry torpedoes. They were built at the Umoe Mandal yard. With a maximum speed of 60 knots (110 km/h), the Skjold-class corvettes were the fastest combat ships afloat at the time of their introduction.
A small waterplane area twin hull, better known by the acronym SWATH, is a catamaran design that minimizes hull cross section area at the sea's surface. Minimizing the ship's volume near the surface area of the sea, where wave energy is located, minimizes a vessel's response to sea state, even in high seas and at high speeds. The bulk of the displacement necessary to keep the ship afloat is located beneath the waves, where it is less affected by wave action. Wave excitation drops exponentially as depth increases, so wave action normally does not affect a submerged submarine at all. Placing the majority of a ship's displacement under the waves is similar in concept to creating a ship that rides atop twin submarines.
Sponsons are projections extending from the sides of land vehicles, aircraft or watercraft to provide protection, stability, storage locations, mounting points for weapons or other devices, or equipment housing.
A stealth ship is a ship that employs stealth technology construction techniques in an effort to make it harder to detect by one or more of radar, visual, sonar, and infrared methods.
A surface effect ship (SES) or sidewall hovercraft is a watercraft that has both an air cushion, like a hovercraft, and twin hulls, like a catamaran. When the air cushion is in use, a small portion of the twin hulls remains in the water. When the air cushion is turned off ("off-cushion" or "hull borne"), the full weight of the vessel is supported by the buoyancy of the twin hulls.
A ground-effect vehicle (GEV), also called a wing-in-ground-effect (WIG), ground-effect craft, wingship, flarecraft or ekranoplan, is a vehicle that is able to move over the surface by gaining support from the reactions of the air against the surface of the earth or water. Typically, it is designed to glide over a level surface by making use of ground effect, the aerodynamic interaction between the moving wing and the surface below. Some models can operate over any flat area such as frozen lakes or flat plains similar to a hovercraft.
Forces on sails result from movement of air that interacts with sails and gives them motive power for sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and sail-powered land vehicles. Similar principles in a rotating frame of reference apply to windmill sails and wind turbine blades, which are also wind-driven. They are differentiated from forces on wings, and propeller blades, the actions of which are not adjusted to the wind. Kites also power certain sailing craft, but do not employ a mast to support the airfoil and are beyond the scope of this article.
The Dyugon-class landing craft, or Project 21820, is a class of five air-cavity landing craft in service with the Russian Navy.
The Serna class, Russian designation Project 11770, is a class of air cavity system landing craft constructed for the Russian Navy. Twelve boats were built by Vostochnaya Verf between 1994 and 2014. Four boats of the export project 11771 were built in 1994.
Splinter fleet or Splinter navy was a nickname given to the United States wooden boats used in World War II. The boats served in many different roles during the war. These boats were built in small boatyards on the West coast and East coast, Great Lakes and the Gulf of Mexico. They could be built quickly, in just 60 to 120 days. Most of the boats were built by boatyards that already had the tools and knowledge from building yachts, sailboats and motor boats. Many were built by craftsmen in family-owned small businesses. Under the Emergency Shipbuilding Program and War Shipping Administration contracts went out to over fifty boatyards across the country. The boats were built for the US Navy, the United States Army Air Forces, United States Coast Guard, and US Army. Some of the wooden boats went to Allied nations on the Lend-Lease program.
The Raptor-class patrol boat, formally identified as Project 03160, is a series of Russian high-speed coastal patrol boats. Boats of the class belong to the 4th rank ships in the Russian Navy. This project was developed by the design bureau of JSC Leningrad Shipyard Pella on the instructions of the Russian Navy. The boats are built at the Pella shipyard in the town of Otradnoye, Leningrad Region. Due to the great similarity in appearance, the boats of the project can be confused with the Swedish CB90-class fast assault craft and other transport and landing boats of the 02510 BK-16 project, developed by the Kalashnikov concern and manufactured at Rybinsk shipyard.
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