Sub Marine Explorer is a submersible built between 1863 and 1866 by Julius H. Kroehl and Ariel Patterson in Brooklyn, New York for the Pacific Pearl Company.

The problems of decompression do not appear to have been clearly understood; the contemporary reference notes that at the conclusion of the dives, "all the men were again down with fever; and, it being impossible to continue working with the same men for some time, it was decided, the experiment having proved a complete success, to lay the machine up in an adjacent cove...."(The New York Times, August 29, 1869).

Experimental dives with the Sub Marine Explorer in the Bay of Panama ended in September 1867 when Kroehl died of "fever".

[citation needed] The submarine's rusting hull was well-known to locals, but they had presumed it to be a remnant of World War II.

In 2001, after many years of misidentification, the remains of the Sub Marine Explorer piqued the interest of archaeologist James P. Delgado of the Institute of Nautical Archaeology.

Identification of the craft, with the assistance of submarine historians Richard Wills and Eugene Canfield, led to four archaeological expeditions to the Explorer in 2002, 2004, 2006, and 2008.