Sub Marine Explorer

The Sub Marine Explorer is a submarine built between 1863 and 1866 by Julius H. Kroehl and Ariel Patterson in Brooklyn, New York for the Pacific Pearl Company.It was hand powered and had an interconnected system of a high-pressure air chamber or compartment, a pressurized working chamber for the crew, and water ballast tanks. Problems with decompression sickness led to the abandonment of the Sub Marine Explorer in Panama in 1869 despite publicized plans to shift the craft to the pearl beds of Baja California.

Construction

Sub Marine Explorer had an external large volume (560 sq. ft.) high air pressure chamber which was filled with compressed air at a pressure of up to 200 pounds per square inch by a steam pump mounted on an external support vessel. Water ballast tanks were flooded to make the Sub Marine Explorer descend. Pressurized air was then released into the vessel to build up enough pressure so it would be possible to open two hatches on the underside, while keeping water out. This meant that air pressure inside the submarine had to equal water pressure at diving depth, exposing the crew to high pressure, making them susceptible to decompression sickness, which was unknown at the time. To ascend back to the surface, more of the pressurized air was used to empty the ballast tanks of water. A contemporary (1869) newspaper account of dives in Sub Marine Explorer off Panama documents 11 days of diving to 103 feet, spending four hours per dive, and ascending with a quick release of the pressure to ambient (sea level) pressure. Modern reconstruction of Explorer's systems suggests an ascension rate of one foot per second; or a rise to the surface in just under two minutes. Even if it took longer to rise, decompression sickness would have been a factor. Using now standard U.S. Navy diving tables, the men inside Explorer would have exceeded their no-decompression limit in 25 minutes at 103 feet. After a two hour dive (half of the documented time spent) a decompression schedule of one hour, 32 minutes and 40 seconds was required with staged stops at 30, 20 and 10 feet. 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 laythe machine up in an adjacent cove....(New York Times, August 29, 1869).

The basic premise of Sub Marine Explorer was based on an earlier 1858 patent by Van Buren Ryerson of New York for a diving bell also named "Sub Marine Explorer." Ryerson and Kroehl had worked together, Kroehl using Ryerson's bell to blast and partially clear Diamond Reef in New York harbor. Kroehl extensively modified Ryerson's design, extending the hull form to a 12 meter long, 3.3 meter diameter craft of intricate design. While some have termed Kroehl's Explorer a "glorified diving bell," its sophisticated systems of ballast, pressurization and propulsion make it a nineteenth century antecedent to more modern "lock out" dive systems and subs.

History

After having been built, the Sub Marine Explorer was partially disassembled and transported to Panama in March 1866, where she was reassembled to harvest oysters and pearls in the Pearl Islands. Experimental dives with the Sub Marine Explorer led to the death of Kroehl in 1867, possibly from decompression sickness, although the cause of death was listed as "fever." The 1869 dives, with known depths and dive profiles that would have inevitably led to decompression sickness, note the entire crew was down with "fever." and the craft was laid up in a cove on the shores of the island of "San Telmo".

The wreck of the Sub Marine Explorer was rediscovered on "San Telmo" in the Pearl Islands in 2001 by archaeologist James P. Delgado of the Institute of Nautical Archaeology. The wreck was well-known to locals, but was assumed to be a remnant of the Second World War. Identification of the craft, with the assistance of submarine historian Richard Wills, led to three separate archaeological expeditions to the Explorer in 2002, 2004 and 2006, with a fourth expedition tentatively planned for 2008. Documentation of Explorer has resulted in detailed plans, including interpretive reconstructions of the craft, scientific study of its environment and interaction with the surrounding water, bathymetric assessment, scientific analysis of rates of corrosion, and considerable historical research. Work in 2006 was funded by the National Oceanic and Atmospheric Administration through the Office of Ocean Exploration. The vessel is now included in the Historic American Engineering Record of the U.S. National Park Service. A recent (2007) report summarizes preservation options for the submarine for the Panamanian government and recommends the recovery, preservation and public display of the craft in Panama. Metal analysis confirms that the craft is in a critical stage and faces irreversible deterioration and loss.

References

* James P. Delgado (2006) "Archaeological Reconnaissance of the 1865 American-Built Sub Marine Explorer at Isla San Telmo, Archipielago de las Perlas, Panama" International Journal of Nautical Archaeology 35 (2), 230–252.

See also

* H.L. Hunley (launched in 1863)

External links

* [http://www.sha.org/underwater/news/06jan.htm#panama The "Society for Historical Archaeology" on the "Sub Marine Explorer Project"]
* [http://www.olgoat.com/explorer/explorer.htm „Civil War-Era Sub Linked with Earliest Deaths from the “Bends””]
* [http://www.timesonline.co.uk/article/0,,2-1642355,00.html „American Civil War submarine found”; TimesOnline, June 2005]