Shipping through the Straits of Florida, and therefore the number of wrecks on the Florida Reef, declined sharply during the Civil War. Following the Civil War, the number of wrecks did not increase as fast as the ship traffic through the Straits. More lighthouses were in place, better charts were available, and more ships were powered by steam and thus less vulnerable to being pushed onto reefs by unfavorable winds. Steam-powered vessels began to enter the wrecking trade. Eventually ocean-going tugboats took over what became known as marine salvage operations. By the end of the 19th century wrecks were infrequent. The last major wrecking operation was in 1905, when 77 small vessels and 500 men salvaged cargo from the steamer "Alicia". Salvage work was abandoned when divers refused to continue, as contaminated water in the hold was causing them to become blind for 24 hours after a dive. The salvage award was US$17,690. The last local wrecker was bought out by a New York company in 1920. The Federal court closed the book of wrecking licenses the next year.