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

submersible A submersible is an underwater vehicle which needs to be transported and supported by a larger ship, watercraft or dock, platform. This distinguishes submersibles from submarines, which are self-supporting and capable of prolonged independent ope ...

used by the

United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

between 1970 and 1986 to oversee and observe undersea construction work. NEMO had a spherical transparent acrylic 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 ''Alvin'' (DSV-2) is a crewed deep-ocean research submersible owned by the United States Navy and operated by the Woods Hole Oceanographic Institution (WHOI) of Woods Hole, Massachusetts. The original vehicle was built by General Mills' Electro ...

'' 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; ) is a civilian foreign intelligence service of the federal government of the United States tasked with advancing national security through collecting and analyzing intelligence from around the world and ...

) 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) is a synthetic polymer derived from methyl methacrylate. It is a transparent thermoplastic, used as an engineering plastic. PMMA is also known as acrylic, acrylic glass, as well as by the trade names and bran ...

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

lead acid battery Lead () is a chemical element; it has symbol Pb (from 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, lea ...

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 Ballast is dense material used as a weight to provide stability to a vehicle or structure. Ballast, other than cargo, may be placed in a vehicle, often a ship or the gondola of a balloon or airship, to provide stability. A compartment within ...

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 islan ...

, 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 deve ...

Naval Air Station Point Mugu Naval Air Station Point Mugu was a United States naval air station near Oxnard, California, which operated as an independent base from 1941 to 2000, when it merged with nearby Naval Construction Battalion Center Port Hueneme to form Naval Base ...

in California, under contract for and in cooperation with the Naval Civil Engineering Laboratory (NCEL), now the

Naval Facilities Engineering Command The Naval Facilities Engineering Systems Command (NAVFAC) is the United States Navy's engineering systems command, providing the Navy and United States Marine Corps with facilities and expeditionary expertise. NAVFAC is headquartered at the Wash ...

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 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. Ratings The hull of a submarine must be able to withs ...

of . NCEL evaluated NEMO in the

Bahamas The Bahamas, officially the Commonwealth of The Bahamas, is an archipelagic and island country within the Lucayan Archipelago of the Atlantic Ocean. It contains 97 per cent of the archipelago's land area and 88 per cent of its population. ...

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 Forces (NCF). The Seabee nickname is a heterograph of the initial letters "CB" from the words "Construction Battalion". Dependi ...

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 A submarine ...

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

Channel Islands The Channel Islands are an archipelago in the English Channel, off the French coast of Normandy. They are divided into two Crown Dependencies: the Jersey, Bailiwick of Jersey, which is the largest of the islands; and the Bailiwick of Guernsey, ...

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 Naval Base Ventura County (NBVC) is a United States Navy base in Ventura County, California. Formed by the merger of Naval Air Station Point Mugu, NAS Point Mugu and Naval Construction Battalion Center Port Hueneme, CBC Port Hueneme, NBVC is a d ...

Port Hueneme, California Port Hueneme ( ; Chumashan languages, Chumash: ''Wene Me'') is a small beach city in Ventura County, California, surrounded by the city of Oxnard, California, Oxnard and the Santa Barbara Channel. Both the Port of Hueneme and Naval Base Ventura ...

, where it is still on display.

Design

Operational history

See also

References

Further reading