Inventor John Holland started submarine design studies in the 1870s. In 1900, the U.S. Navy bought one of his boats -- really a minisub -- and commissioned it as the USS Holland (SS-1).
The Holland was armed with a single 18-inch torpedo and a pneumatic dynamite gun. It had a crew of six. Other particulars can be found in the Wikipedia article.
Holland was decommissioned in 1905.
https://en.wikipedia.org/wiki/USS_Holland_(SS-1)
I served (on temporary duty) on submarines, but there is NO WAY you could get me on something like this!