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-inch (450 mm) torpedo tubes in the bow. They carried four reloads, for a total of eight torpedoes.[2]
H-7 was launched on 17 October 1918 and commissioned on 24 October. The submarine, attached to Submarine Division 6 (SubDiv 6) and later to SubDiv 7, operated out of San Pedro, California, on various battle and training exercises with the other ships of her division. She also patrolled out of San Pedro with interruptions for overhaul at Mare Island. H-7 reached Norfolk on 14 September 1922, having sailed from San Pedro on 25 July, and decommissioned there on 23 October. Her name was struck from the Naval Vessel Register on 26 February 1931. She was sold for scrapping on 28 November 1933.