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Depth ratings are primary design parameters and measures of a submarine's ability to operate underwater. The depths to which submarines can dive are limited by the strengths of their hulls.
The hull of a submarine must be able to withstand the forces created by the outside water pressure being greater than the inside air pressure. The outside water pressure increases with depth and so the stresses on the hull also increase with depth. Each 10 metres (33 feet) of depth puts another atmosphere (1 bar, 14.7 psi, 101 kPa) of pressure on the hull, so at 300 metres (1,000 feet), the hull is withstanding thirty atmospheres (30 bar, 441 psi, 3,000 kPa) of water pressure.
This is the maximum depth at which a submarine is permitted to operate under normal peacetime circumstances, and is tested during sea trials. The test depth is set at two-thirds (0.66) of the design depth for United States Navy submarines, while the Royal Navy sets test depth at 4/7 (0.57) the design depth, and the German Navy sets it at exactly one-half (0.50) of design depth. [1]
Also known as the maximum operating depth (or the never-exceed depth), this is the maximum depth at which a submarine is allowed to operate under any (e.g. battle) conditions.
The nominal depth listed in the submarine's specifications. From it the designers calculate the thickness of the hull metal, the boat's displacement, and many other related factors.
Sometimes referred to as the "collapse depth" in the United States, [2] [ citation needed ] this is the submerged depth at which the submarine implodes due to water pressure. Technically speaking, the crush depth should be the same as the design depth, but in practice is usually somewhat deeper. This is the result of compounding safety margins throughout the production chain, where at each point an effort is made to at least slightly exceed the required specifications to account for imperceptible material defects or variations in machining tolerances.
A submarine, by definition, cannot exceed crush depth without being crushed. However, when a prediction is made as to what a submarine's crush depth might be, that prediction may subsequently be mistaken for the actual crush depth of the submarine. Such misunderstandings, compounded by errors in translation and general confusion as to what the various depth ratings mean, have resulted in multiple erroneous accounts of submarines not being crushed at their crush depth.
Notably, several World War II submarines reported that, due to flooding or mechanical failure, they'd gone below crush depth, before successfully resurfacing after having the failure repaired or the water pumped out. In these cases, the "crush depth" is always either a mistranslated official "safe" or design depth (i.e. the test depth, or the maximum operating depth) or a prior (incorrect) estimate of what the crush depth might be. World War II German U-boats of the types VII and IX generally imploded at depths of 200 to 280 m (660 to 920 ft).[ citation needed ]
Trieste is a Swiss-designed, Italian-built deep-diving research bathyscaphe. In 1960, it became the first crewed vessel to reach the bottom of Challenger Deep in the Mariana Trench, the deepest point in Earth's seabed. The mission was the final goal for Project Nekton, a series of dives conducted by the United States Navy in the Pacific Ocean near Guam. The vessel was piloted by Swiss oceanographer Jacques Piccard and US Navy lieutenant Don Walsh. They reached a depth of about 10,916 metres (35,814 ft).
A submarine is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely operated vehicles and robots, as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub. Submarines are referred to as boats rather than ships irrespective of their size.
HMAS Collins is the lead vessel of the six-submarine Collins class operated by the Royal Australian Navy (RAN).
A submersible is an underwater vehicle which needs to be transported and supported by a larger watercraft or platform. This distinguishes submersibles from submarines, which are self-supporting and capable of prolonged independent operation at sea.
In underwater diving activities such as saturation diving, technical diving and nitrox diving, the maximum operating depth (MOD) of a breathing gas is the depth below which the partial pressure of oxygen (pO2) of the gas mix exceeds an acceptable limit. This limit is based on risk of central nervous system oxygen toxicity, and is somewhat arbitrary, and varies depending on the diver training agency or Code of Practice, the level of underwater exertion expected and the planned duration of the dive, but is normally in the range of 1.2 to 1.6 bar.
A deep-submergence vehicle (DSV) is a deep-diving crewed submersible that is self-propelled. Several navies operate vehicles that can be accurately described as DSVs. DSVs are commonly divided into two types: research DSVs, which are used for exploration and surveying, and DSRVs, which are intended to be used for rescuing the crew of a sunken navy submarine, clandestine (espionage) missions, or both. DSRVs are equipped with docking chambers to allow personnel ingress and egress via a manhole.
An atmospheric diving suit (ADS) is a small one-person articulated submersible which resembles a suit of armour, with elaborate pressure joints to allow articulation while maintaining an internal pressure of one atmosphere. An ADS can enable diving at depths of up to 700 metres (2,300 ft) for many hours by eliminating the majority of significant physiological dangers associated with deep diving. The occupant of an ADS does not need to decompress, and there is no need for special breathing gas mixtures, so there is little danger of decompression sickness or nitrogen narcosis when the ADS is functioning properly. An ADS can permit less skilled swimmers to complete deep dives, albeit at the expense of dexterity.
USS M-1 (SS-47) was a unique submarine of the United States Navy. Although built as a fully operational boat, M-1 was built with a radically different double-hulled design. This was in marked contrast to Simon Lake's and Electric Boat's single-hulled concepts. Ultimately shown to be unsuccessful, no other submarines of this class were built, although future advances in construction and metallurgy science made the double hull design a standard one for the USN.
The K-class submarines were a class of steam-propelled submarines of the Royal Navy designed in 1913. Intended as large, fast vessels with the endurance and speed to operate with the battle fleet, they gained notoriety and the nickname of "Kalamity class" for being involved in many accidents. Of the 18 built, none were lost through enemy action, but six sank, with significant loss of life, in accidents. Only one ever engaged an enemy vessel, K-7 hitting a U-boat amidships, though the torpedo failed to explode with what has been described as typical "K" luck; K-7 escaped retaliation by steaming away at speed.
The SP-350 Denise, famous as the "Diving saucer", is a small submarine designed to hold two people, and is capable of exploring depths of up to 400 metres (1,300 ft). It was invented by Jacques-Yves Cousteau and engineer Jean Mollard at the French Centre for Undersea Research. It was built in the year 1959 and usually operated from Cousteau's ship, the Calypso.
A diving chamber is a vessel for human occupation, which may have an entrance that can be sealed to hold an internal pressure significantly higher than ambient pressure, a pressurised gas system to control the internal pressure, and a supply of breathing gas for the occupants.
Water Resistant is a common mark stamped on the back of wrist watches to indicate how well a watch is sealed against the ingress of water. It is usually accompanied by an indication of the static test pressure that a sample of newly manufactured watches were exposed to in a leakage test. The test pressure can be indicated either directly in units of pressure such as bar, atmospheres, or as an equivalent water depth in metres.
A submarine hull has two major components, the light hull and the pressure hull. The light hull of a submarine is the outer non-watertight hull which provides a hydrodynamically efficient shape. The pressure hull is the inner hull of a submarine that maintains structural integrity with the difference between outside and inside pressure at depth.
Aluminaut was the world's first aluminum submarine. An experimental vessel, the 80-ton, 15.5-metre (51 ft) crewed deep-ocean research submersible was built by Reynolds Metals Company, which was seeking to promote the utility of aluminum. Aluminaut was based in Miami, Florida, and was operated from 1964 to 1970 by Reynolds Submarine Services, doing contract work for the U.S. Navy and other organizations, including marine biologist Jacques Cousteau.
The breathing performance of regulators is a measure of the ability of a breathing gas regulator to meet the demands placed on it at varying ambient pressures and temperatures, and under varying breathing loads, for the range of breathing gases it may be expected to deliver. Performance is an important factor in design and selection of breathing regulators for any application, but particularly for underwater diving, as the range of ambient operating pressures and temperatures, and variety of breathing gases is broader in this application. A diving regulator is a device that reduces the high pressure in a diving cylinder or surface supply hose to the same pressure as the diver's surroundings. It is desirable that breathing from a regulator requires low effort even when supplying large amounts of breathing gas as this is commonly the limiting factor for underwater exertion, and can be critical during diving emergencies. It is also preferable that the gas is delivered smoothly without any sudden changes in resistance while inhaling or exhaling, and that the regulator does not lock up and either fail to supply gas or free-flow. Although these factors may be judged subjectively, it is convenient to have standards by which the many different types and manufactures of regulators may be objectively compared.
Project Nekton was the codename for a series of very shallow test dives and also deep-submergence operations in the Pacific Ocean near Guam that ended with the United States Navy-owned research bathyscaphe Trieste entering the Challenger Deep, the deepest surveyed point in the world's oceans.
DeepFlight Challenger is a one-person submersible built with the intention of reaching the Challenger Deep, utilizing DeepFlight technology from Hawkes Ocean Technologies. The submersible is owned by Virgin Oceanic.
HY-80 is a high-tensile, high yield strength, low alloy steel. It was developed for use in naval applications, specifically the development of pressure hulls for the US nuclear submarine program and is still currently used in many naval applications. It is valued for its strength to weight ratio.
Charles Brun was one of four experimental submarines ordered for the French Navy in 1906. Each boat was built to a different design and Charles Brun was intended to test a novel powerplant. Although the shore-based prototype installation was successful, it was a failure when evaluated aboard the submarine, and the boat was never commissioned for active service. Her hull was stripped of its equipment and was used to test a floating drydock in 1914. During the First World War, the hull was ordered to be converted into a water tank in 1916, but it is not certain if this was actually done before it was sold for scrap in 1920.
The metresea water (msw) is a metric unit of pressure used in underwater diving. It is defined as one tenth of a bar.