Argonaut Junior was the first successful submarine built by the American engineer Simon Lake.

Her main attribute, like that of the sub built by Lake in 1897, Argonaut, was an air lock.

[3] Argonaut Junior was built in 1894 as a prototype by Lake after he was denied a contract by the U.S. Navy.

It was triangular, made of wood (yellow pine), and had three wheels to keep it from getting stuck to the sea bottom.

She moved along the bottom of Sandy Hook Bay by one or two men cranking the axle of the two driving wheels.