DSV-5, ex-NEMO (Naval Experimental Manned Observatory), was a submersible used by the United States Navy between 1970 and 1986 to oversee and observe undersea construction work.

[2] 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.

[7] NEMO's mission was to test the feasibility and utility of an all-acrylic spherical hull and then to support underwater construction, repair, and salvage work.

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.

[2] NEMO provided a shirt-sleeve environment for nondiving engineers, technicians, and scientists to oversee undersea construction, allowing them to see and communicate with divers for the first time.

[8] 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,[2] where it is still on display.