The H-class submarines had a length of 150feet overall, a beam of 15feet and a mean draft of 12feet. They displaced 358LT on the surface and 467LT submerged. The boats had a crew of 2 officers and 23 enlisted men. They had a diving depth of 200feet.[1]
For surface running, they were powered by two New London Ship & Engine Co. 4750NaN0 diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 170hp Electro Dynamic Co. electric motor. They could reach 14kn on the surface and underwater.[1] On the surface, the boats had a range of 2300nmi at and 100nmi at submerged.[2]
The boats were armed with four 18 -nch (450 mm) torpedo tubes in the bow. They carried four reloads, for a total of eight torpedoes.[2]
H-9 was launched on 23 November 1918 and commissioned on 25 November. Joining Submarine Division 6 (SubDiv 6) at San Pedro, Los Angeles, and later being transferred to SubDiv 7 there, H-9 participated in a variety of battle and training exercises along the West Coast. She also patrolled off Santa Catalina Island, and put in at Mare Island for periodic overhauls.
H-9 sailed from San Pedro on 25 July 1922 and arrived in Norfolk, Virginia on 14 September, with SubDivs 6 and 7. The submarine decommissioned at Norfolk on 3 November. Her name was struck from the Naval Vessel Register on 26 February 1931. She was sold for scrapping on 28 November 1933.