While at Yale, Bushnell proved that gunpowder could be exploded under water. He also made the first time bomb. He combined these ideas by building the Turtle which was designed to attack ships by attaching a time bomb to their hulls, while using a hand powered drill and ship auger bit to penetrate the hulls. He used the Turtle in attempts to attack British ships which were blockading New York Harbor in the summer of 1776. His efforts failed every time because the Turtle's boring device was unable to penetrate the copper sheeting lining in the ships' hulls which was designed to protect against parasites in their previous station, the Caribbean. The Turtle eventually sank when it was trying to retreat from British observation, yet a Bushnell family member as sole commander, bailed out and su