DSV-5, ex-NEMO (Naval Experimental Manned Observatory), was a

submersible A submersible is a small watercraft designed to operate underwater. The term "submersible" is often used to differentiate from other underwater vessels known as submarines, in that a submarine is a fully self-sufficient craft, capable of ind ...

used by the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

between 1970 and 1986 to oversee and observe undersea construction work. NEMO had a spherical transparent

acrylic Acrylic may refer to: Chemicals and materials * Acrylic acid, the simplest acrylic compound * Acrylate polymer, a group of polymers (plastics) noted for transparency and elasticity * Acrylic resin, a group of related thermoplastic or thermosett ...

hull, which gave occupants panoramic vision. NEMO was the first submersible with a hull made entirely out of transparent acrylic (Plexiglass), and much of her career was spent testing this hull design. NEMO was found to be an effective observation platform, despite not being able to hover in place, and acrylic-hulled submersibles have continued to be built and operated in the United States. NEMO is considered part of the '' Alvin'' class of

Deep Submergence Vehicle 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 ex ...

s despite bearing little resemblance to the other subs of the class. NEMO was transferred to "other government agencies" (likely the

CIA The Central Intelligence Agency (CIA ), known informally as the Agency and historically as the Company, is a civilian intelligence agency, foreign intelligence service of the federal government of the United States, officially tasked with gat ...

) in 1986 and retired from government service in 2011. It was then given to the U.S. Navy Seabee Museum, where it remains on display.

Design

NEMO consisted of a spherical pressure hull with a inside diameter and a outside diameter, plus outside life support and operational subsystems housed below the crew compartment. The hull was made from thick transparent acrylic,

Poly(methyl methacrylate) Poly(methyl methacrylate) (PMMA) belongs to a group of materials called engineering plastics. It is a transparent thermoplastic. PMMA is also known as acrylic, acrylic glass, as well as by the trade names and brands Crylux, Plexiglas, Acrylite, ...

, and housed a crew of two (pilot and observer). Operational subsystems included a main

lead acid battery Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, le ...

power supply, electrical distribution and control circuitry, a hydraulic system to operate a self-contained winch/anchor system, and two side-mounted thrusters for rotation and limited horizontal movement. A compressed air ballast system was used for controlling buoyancy. NEMO was untethered and relied on its own batteries for power. NEMO also carried a radio for communicating with NEMO's mothership, divers, or other submersibles. NEMO was designed for depths of up to , the depth of the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

, although it was later certified for depths. Its deepest recorded dive was . Its life support system gave it an endurance of 8 hours, though it also had an emergency backup system that could provide up to an additional 24 hours. NEMO weighed and could carry a payload of . The side thrusters could propel NEMO at speeds of up to .

Operational history

NEMO was built alongside two additional hulls by the

Southwest Research Institute Southwest Research Institute (SwRI), headquartered in San Antonio, Texas, is an independent and nonprofit applied research and development (R&D) organization. Founded in 1947 by oil businessman Tom Slick, it provides contract research and develop ...

at Naval Air Station Point Mugu in California, under contract for and in cooperation with the Naval Civil Engineering Laboratory (NCEL), now the Naval Facilities Engineering Command Engineering Service Center. NEMOs mission was to test the feasibility and utility of an all-acrylic spherical hull and then to support underwater construction, repair, and salvage work. Its other two hulls were used for fatigue and collapse testing, which found a crush depth of . NCEL evaluated NEMO in the

Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...

between 1970 and 1972, performing over 100 dives. The evaluation concluded that NEMO was an effective, comfortable, safe, and reliable underwater observation platform, although its usefulness was hindered by the lack of a hovering capability. Following its evaluation, NEMO was used by the Navy

Seabees United States Naval Construction Battalions, better known as the Navy Seabees, form the U.S. Naval Construction Force (NCF). The Seabee nickname is a heterograph of the initial letters "CB" from the words "Construction Battalion". Depending upon ...

to observe and monitor undersea construction. NEMO provided a

shirt-sleeve environment "Shirt-sleeve environment" is a term used in aircraft design to describe the interior of an aircraft in which no special clothing need be worn. Early aircraft had no internal pressurization, so the crews of those that reached the stratosphere ...

for nondiving engineers, technicians, and scientists to oversee undersea construction, allowing them to see and communicate with divers for the first time. It played an important role in

undersea cable Submarine cable is any electrical cable that is laid on the seabed, although the term is often extended to encompass cables laid on the bottom of large freshwater bodies of water. Examples include: *Submarine communications cable *Submarine power ...

laying and maintenance. NEMO made several hundred dives off the Bahamas and

Channel Islands The Channel Islands ( nrf, Îles d'la Manche; french: îles Anglo-Normandes or ''îles de la Manche'') are an archipelago in the English Channel, off the French coast of Normandy. They include two Crown Dependencies: the Bailiwick of Jersey, ...

over the course of its Navy career. DSV-5 submerged

NEMO was transferred to "other government agencies" (likely the

) on 30 September 1986. Details about its activities since being transferred are obscured. In July 2011, NEMO left government service and was transferred to the U.S. Navy Seabee Museum at Naval Base Ventura County, Port Hueneme, California, where it is still on display.

Design

Operational history

See also

References

Further reading