A multihull is a boat or ship with more than one hull, whereas a vessel with a single hull is a monohull. The most common multihulls are catamarans, and trimarans. There are other types, with four or more hulls, but such examples are very rare and tend to be specialised for particular functions.
Naval architecture, or naval engineering, is an engineering discipline incorporating elements of mechanical, electrical, electronic, software and safety engineering as applied to the engineering design process, shipbuilding, maintenance, and operation of marine vessels and structures. Naval architecture involves basic and applied research, design, development, design evaluation (classification) and calculations during all stages of the life of a marine vehicle. Preliminary design of the vessel, its detailed design, construction, trials, operation and maintenance, launching and dry-docking are the main activities involved. Ship design calculations are also required for ships being modified. Naval architecture also involves formulation of safety regulations and damage-control rules and the approval and certification of ship designs to meet statutory and non-statutory requirements.
A seaplane is a powered fixed-wing aircraft capable of taking off and landing (alighting) on water. Seaplanes are usually divided into two categories based on their technological characteristics: floatplanes and flying boats; the latter are generally far larger and can carry far more. Seaplanes that can also take off and land on airfields are in a subclass called amphibious aircraft, or amphibians. Seaplanes were sometimes called hydroplanes, but currently this term applies instead to motor-powered watercraft that use the technique of hydrodynamic lift to skim the surface of water when running at speed.
An amphibious aircraft or amphibian is an aircraft that can take off and land on both solid ground and water. They are typically fixed-wing, though amphibious helicopters do exist as well. Fixed-wing amphibious aircraft are seaplanes which are equipped with retractable wheels, at the expense of extra weight and complexity, plus diminished range and fuel economy compared to planes designed specifically for land-only or water-only operation. Some amphibians are fitted with reinforced keels which act as skis, allowing them to land on snow or ice with their wheels up.
A pontoon bridge, also known as a floating bridge, uses floats or shallow-draft boats to support a continuous deck for pedestrian and vehicle travel. The buoyancy of the supports limits the maximum load that they can carry.
A trimaran is a multihull boat that comprises a main hull and two smaller outrigger hulls which are attached to the main hull with lateral beams. Most modern trimarans are sailing yachts designed for recreation or racing; others are ferries or warships. They originated from the traditional double-outrigger hulls of the Austronesian cultures of Maritime Southeast Asia; particularly in the Philippines and Eastern Indonesia, where it remains the dominant hull design of traditional fishing boats. Double-outriggers are derived from the older catamaran and single-outrigger boat designs.
A floating dock, floating pier or floating jetty is a platform or ramp supported by pontoons. It is usually joined to the shore with a gangway. The pier is usually held in place by vertical poles referred to as pilings, which are embedded in the seafloor or by anchored cables. Frequently used in marinas, this type of pier maintains a fixed vertical relationship to watercraft secured to it, independent of tidal, river or lake elevation. The angle of the gangway varies with the water level.
A floatplane is a type of seaplane with one or more slender floats mounted under the fuselage to provide buoyancy. By contrast, a flying boat uses its fuselage for buoyancy. Either type of seaplane may also have landing gear suitable for land, making the vehicle an amphibious aircraft. British usage is to call floatplanes "seaplanes" rather than use the term "seaplane" to refer to both floatplanes and flying boats.
Very large floating structures (VLFSs) or very large floating platforms (VLFPs) are artificial islands, which may be constructed to create floating airports, bridges, breakwaters, piers and docks, storage facilities, wind and solar power plants, for military purposes, to create industrial space, emergency bases, entertainment facilities, recreation parks, mobile offshore structures and even for habitation. Currently, several different concepts have been proposed for building floating cities or huge living complexes. Some units have been constructed and are presently in operation.
A pontoon boat is a flattish boat that relies on floats to remain buoyant. These pontoons contain much reserve buoyancy and allow designers to create large deck plans fitted with a variety of accommodations including expansive lounge areas, stand-up bars, and sun pads. Better tube designs have allowed builders to put ever-increasing amounts of horsepower on the stern. Pontoon boat drafts may be as shallow as eight inches, which reduces risk of running aground and underwater damage, this allows it to come close to shore to pick up and drop off loads.
The Navy Lighterage pontoon (NLP) was a type of pontoon developed in World War II by Capt. John N. Laycock Civil Engineer Corps (CEC) and used by United States Navy Construction Battalions(Seabees) on invasion beaches and shallow harbors or harbors where the facilities had been destroyed or did not exist. It was referred to as the Seabee's "magic box". It was Lego-like system of pre-cut pre-drilled angle iron and steel plate. It was first assembled into individual boxes that were joined in multiples to construct docks, causeways, barges, dry docks, floating cranes, marine railways or whatever was needed.
A rhino ferry is a barge constructed from several pontoons which are connected and equipped with outboard engines, used to transport heavy equipment and people. Rhino ferries were used extensively during the Normandy landings and other theaters ; their low draft was well-suited for shallow beaches, and they could also be used as piers when filled with water. An alternative to tank landing craft, they were operated by United States Navy Construction Battalions. They ferried their cargo from the outlying Landing Ships, Tank to the shore.
Naval Base Ulithi was a major United States Navy base at the Ulithi Atoll in the Caroline Islands in the western Pacific Ocean, to the north of New Guinea during World War II. The base was built to support the island-hopping Pacific war efforts of the Allied nations fighting the Empire of Japan. In terms of the number of ships at one base, Naval Base Ulithi was the largest naval base in the world in 1944 and 1945, with over 600 ships at times.
Naval Base Milne Bay, also called Naval Advance Base Milne Bay, was new major United States Navy sea and airbase base built on Milne Bay in Milne Bay Province in south-eastern Papua New Guinea. By spring 1943, the build up of the US Navy to support the Pacific War had caused overcrowding at the ports on the east coast of Australia. To help, Seabees departed Naval Base Brisbane on June 19, 1943 to set up a new base in Milne Bay. Naval Base Milne Bay headquarters was at Ladava Navy Base. The Royal Australian Navy already had a small base in Milne Bay: HMAS Ladava. Australians were able to defend and keep Milne Bay in the Battle of Milne Bay in 1942. Naval Base Milne Bay was built during World War II to support the many ships and aircraft fighting and patrolling in the South West Pacific theatre of war. Ladava Navy Base provided a large protective US Navy fleet anchorage at Gahora Bay next to Ladava. At Naval Base Milne Bay, Seabees built a large Naval facility.
Naval Base Okinawa, now Naval Facility Okinawa, is a number of bases built after the Battle of Okinawa by United States Navy on Okinawa Island, Japan. The naval bases were built to support the landings on Okinawa on April 1, 1945, and the troops fighting on Okinawa. The Navy repaired and did expansion of the airfields on Okinawa. United States Navy Seabees built or repaired the facilities on the island. The bases on Okinawa put the United States Armed Forces only 350 miles from Japan's home islands. Most facilities closed after the war, but some are still in use today by all branches of the United States Armed Forces.
Naval Base Banika Island was a United States Navy base built during World War II on Mbanika Island in the Russell Islands, part of the Solomon Islands. A larger supply depot was built to support the ships fighting in the Pacific War. Also built were a repair base for landing craft, PT boats, and other boats. Banika Island offered excellent fleet anchorage. Banika Island was taken during the Solomon Islands campaign. Also at the base was built the Renard Sound Seaplane Base.
