The remains of the inventor of the first submarine to operate successfully at depth and able to resurface were exhumed on Thursday, October 11, in Panama's Amador cemetery under the direction of the United States  Embassy with the collaboration of the Municipality of Panama.

The rusting hulk of  American German, Julius  Kroehl’s  historic craft, lies in the intertidal zone of Isla San Telmo, the westernmost of the Pearl Islands where it was abandoned  two years after his  death in 1867 and  until spotted by American archeologist Jim Delgado in 2007, was  thought  to be  a two-man Japanese  submarine abandoned after an aborted  attempt to attack the Panama Canal during World War II.

The remains  of Kroehl, born in 1820 in East Prussia, will be  subjected to forensic testing  to confirm the cause of death believed to have  been due to compression sickness from operating his  invention while in search of pearls in, the Las Perlas archipelago but originally listed  as “fever.”

The  brilliant engineer and architect  built Sub Marine Explorer in  Brooklyn, New York between1863 and 1866

In early 1867, her owners, the Pacific Pearl Company of New York, partially dismantled the vessel shipped her piecemeal by steamer to Colon, and then transported her to the Pacific coast on a railcar.

There, Kroehl reassembled and readied the Explorer for dives to harvest pearls and pearl oysters intended to make the designer’s fortune, but eventually leaving his widow leaving a near-pauper as the area had been overfished.

Kroehl had immigrated to New York in 1844.. After a career that included working as a daguerreotype photographer, iron manufacturer, (he had a leading role in building New York's Crystal Palace and a cast-iron fire watch tower that remains standing in New York City's present-day Marcus Garvey Park.

Dimensions
The Sub Marine Explorer was 36 feet long and 10 feet in diameter. Made of cast and wrought iron, she displaced 80 tons. Her hull was divided into three areas: a compressed air chamber lying beneath the hull's turtleback- per hull, an interior working chamber for the crew, and a series of ten ballast tanks. To dive, a steam tender filled the high-pressure chamber with compressed air up to 200 psi. With the chamber charged, Kroehl and his crew opened seacocks from a central control station and y flooded the tanks to start the submarine's descent. As the water rushed in, the displaced air bled into a series of discharge pipes that fed through a central manifold and then exhausted out a valve in the conning tower. Kroehl trimmed the boat by regulating the flooding and with blasts of pressurized air to expel seawater from the ballast tanks.

[caption id="attachment_89539" align="alignleft" width="300"] Jim Delgado[/caption]

Once at depth, Kroehl allowed enough pressured air into the working chamber to equalize with the ambient sea pressure. This allowed the crew to open hatches in the bottom of the submarine and work on the seabed, collecting oysters and pearls. A hand-cranked propeller generated up to four knots of speed, and a system of spraying seawater through chemicals refreshed the air. To surface, enough pressurized air would be released to blow the tanks dry. The Explorer made a series of successful dives, but without Kroeh the project collapsed.

The bends
The Explorer 's only flaw was not one of design but of execution says a US Navy history magazine.  The effects of pressure on the human body were not fully understood, nor how to combat decompression sickness, also known as the bends.

In 1869, following a series of dives off Isla San Telmo, the submarine crew was stricken with what newspapers reported as "fever," while local oral tradition suggests they died after making four-hour-long dives to more than 100 feet and then quickly resurfacing.

Contemporary newspaper accounts confirm the dangerous dives and lengthy exposures to pressure. That definitely led to decompression sickness, which can be fatal.  (The cure for the bends was not discovered until 1907).

https://www.youtube.com/watch?v=pORoqZRUJGM