Cornelis Drebbel's Oar

Origin
Cornelis Drebbel was a Dutch inventor who helped create some of the first optical instruments for scientific use, such as lenses, camera obscuras and telescopes. He also had a heavy interest in chemistry, hydraulics and even constructed the first submarine for the English Royal Navy. He made three wood and leather crafts; the third was propelled by six oars and capable of carrying 16 people for up to three hours unfer the Thames. King James I was even a passenger, becoming the first ruler to travel underwater. Even with all these technological developments, Drebbel had died in near poverty.

Effects
Allows people to stay underwater for three hours without sickness, but prolonged use causes decompression sickness, commonly known as the bends. During uncontrolled diving, dissolved gases will bubble up across the body and cause symptoms ranging from rashes to paralysis, sometimes fatal. Many users must enter a decompression chamber or similar apparatus directly after use or suffer from excruciating pain.