In the 19th century, the fin whale was occasionally hunted by open-boat whalers, but it was relatively safe, because it could easily outrun ships of the time and often sank when killed, making the pursuit a waste of time for whalers. However, the later introduction of steam-powered boats and harpoons that exploded on impact made it possible to kill and secure them along with blue and sei whales on an industrial scale. As other whale species became overhunted, the whaling industry turned to the still-abundant fin whale as a substitute. It was primarily hunted for its blubber, oil, and baleen. Around 704,000 fin whales were caught in Antarctic whaling operations alone between 1904 and 1975.