Drebbels submarine, built of wood and propelled by oars, could stay underwater for several hours.
Floats with attached tubes brought air from the surface to the crew below.
Curious and interested, the Tsar invited Nikonov to Saint-Petersburg and asked him to get down with the construction.
Nikonovs submarine was built out of wood and shaped like a barrel.
It was armed with fire tubes, a weapon akin to flame-throwers.
The first trial of the submarine was conducted in autumn 1724.
It was a disaster.
The submarine sank, hit the bottom and broke the bilge.
Nikonov himself, along with four oarsmen, were inside.
It was only by a miracle that the crew managed to save themselves.
Peter was supportive and encouraged Nikonov to improve the design.
But failures continued to plague Nikonov, especially after the death of his principle patron, Tsar Peter.
Finally, the patience of the Admiralty Board of the Imperial Russian Navy snapped.
The submarine called Turtle was designed by an American inventor David Bushnell.
Hand-cranked propellers provided vertical and horizontal movement with a maximum speed of 4.8 km/h.
The vessel contained enough air for about thirty minutes of operation.
During the American Revolutionary War, the Turtle, operated by Sgt.
However, the only records documenting the attack are American.
Some believe that the entire story around the Turtle was fabricated as disinformation and morale-boosting propaganda.
