American losses at the Battle of Savo Island were high: heavy cruisers Canberra, Vincennes, Astoria and Quincy were sunk and Chicago was under repair until January 1943. Of the destroyers Ralph Talbot was under repair in the U.S. until November 1942 and Patterson was repaired locally.
At the battle of Cape Esperance (October 11 to 12) American heavy cruiser San Francisco (CA-38) and light cruiser Helena (CL-50) were undamaged; light cruiser Boise (CL-47) needed eight months of repairs, and heavy cruiser Salt Lake City (CA-25) needed four months of repairs. The destroyer Duncan (DD-485) was sunk and the destroyer Farenholt (DD-491) needed 5 months of repairs. Destroyers Buchanan (DD-484), Laffey (DD-459) and McCalla (DD-488) were not damaged.
On the Japanese ledger heavy cruiser Aoba was hit by up to forty 6-inch and 8-inch shells. The bridge was wrecked, the No. 2 turret was knocked out and the No. 3 turret destroyed. Other hits put four of the Aoba’s boilers off line. Admiral Goto was mortally wounded and 80 other crewmen were killed. Somehow, she made it back to Shortland and from there to Truk and Japan where repairs took four months.
Heavy cruiser Kinugasa took four hits but was able to fully participate in the bombardment of Henderson Field two days later.
Heavy cruiser Furutaka was sunk as was destroyer Fubuki. The next day destroyers Natsugumo and Murakumo were sunk by land-based planes while trying to assist the cruisers.
A victory for the Americans in most respects. The Japanese Navy could not afford to trade ship losses at anything close to a 1:1 ratio.
During the 1890s Japan built 20 protected cruisers. During the period 1900-1910 Japan built 13 more. None of these were useful during the war.