USS Milwaukee (CL-5) While steaming north of Hispaniola and Puerto Rico on 14 February 1939, "Milwaukee" discovered the deepest place in the Atlantic Ocean. The spot—which has a depth of —is now known as the "Milwaukee Deep". By January 1941, the ship had returned to Cruiser Division 2 which was now assigned to the Caribbean Patrol, commanded by Rear Admiral Jonas H. Ingram, part of the Neutrality Patrol established after the war began. Cruiser Division 2 was ordered to patrol the Atlantic between Trinidad, the Cape Verde Islands and the eastern bulge of Brazil in April, although "Milwaukee" was not immediately available. The
Submarine have used thick acrylic pressure hulls. The deepest deep-submergence vehicle (DSV) to date is "Trieste". On 5 October 1959, "Trieste" departed San Diego for Guam aboard the freighter "Santa Maria" to participate in "Project Nekton", a series of very deep dives in the Mariana Trench. On 23 January 1960, "Trieste" reached the ocean floor in the Challenger Deep (the deepest southern part of the Mariana Trench), carrying Jacques Piccard (son of Auguste) and Lieutenant Don Walsh, USN. This was the first time a vessel, manned or unmanned, had reached the deepest point in the Earth's oceans. The onboard systems indicated