L-class
From PigBoats.COM
USS L-1
USS L-1 riding at anchor while on sea trials, circa 1916, probably off Provencetown, Mass. Just at background sea level a low land mass with houses can be seen such as seen at Cape Cod. The L class were the first US submarine designed to carry a 3"/23 caliber deck gun but it wasn't until the L-9 that guns were installed during construction. The L-1 through L-8 were retrofitted later with the gun. As you can see the L-1 has no gun. The USS M-1 actually had the first deck mounted gun on a US submarine. The two dynamite guns carried by the USS Holland were not deck mounted but built into the pressure hull.