USS Helena (CL-50) was a Brooklyn-class light cruiser built for the United States Navy in the late 1930s, the ninth and final member of the class. The Brooklyn's were the first modern light cruisers built by the US Navy under the limitations of the London Naval Treaty, and they were intended to counter the Japanese Mogami class; as such, they carried a battery of fifteen 6-inch (150 mm) guns, the same gun armament carried by the Mogami's. Helena and her sister St. Louis was built to a slightly modified design with a unified system of machinery and an improved anti-aircraft battery. Completed in late 1939, the first two years of Helena's career consisted of peacetime training that accelerated as tensions between the United States and Japan increased through 1941. She was torpedoed at the attack on Pearl Harbor in December 1941 and was repaired and modernized in early 1942.
After returning to service, Helena was assigned to the forces participating in the Guadalcanal campaign in the south Pacific. There, she took part in two major night battles with Japanese vessels in October and November 1942. The first, the Battle of Cape Esperance on the night of 11–12 October, resulted in a Japanese defeat, with Helena's rapid-fire 6-inch battery helping to sink a heavy cruiser and a destroyer. The second, the first night of the Naval Battle of Guadalcanal in the early hours of 13 November, saw a similar defeat imposed on the Japanese; again, Helena's fast shooting helped to overwhelm a Japanese task force that included two fast battleships, one of which was disabled by heavy American fire and sunk the next day. Helena sank a destroyer and damaged several others in the action while emerging relatively unscathed. During her tour in the south Pacific, she also escorted convoys carrying supplies and reinforcements to the Marines fighting on Guadalcanal and bombarded Japanese positions on the island and elsewhere in the Solomons.
Following the American victory on Guadalcanal in early 1943, Allied forces began preparations to advance along the Solomon chain, first targeting New Georgia. Helena took part in a series of preparatory attacks on the island through mid-1943, culminating in an amphibious assault in the Kula Gulf on 5 July. The next night, while attempting to intercept a Japanese reinforcement squadron, Helena was torpedoed and sunk in the Battle of Kula Gulf. Most of her crew were picked up by a pair of destroyers and one group landed on New Georgia where they were evacuated the next day, but more than a hundred remained at sea for two days, ultimately making land on Japanese-occupied Vella Lavella. There, they were hidden from Japanese patrols by Solomon Islanders and a coastwatcher detachment before being evacuated on the night of 15–16 July. Helena's wreck was located in 2018 by Paul Allen.  wiki