Chainshot is a type of ammunition used in cannon designed to be used to damage masts and rigging. Consisting of two halves of roundshot connected by a chain, upon leaving the gun the shot begins to tumble and the halves would separate to the ends of the chain to maximize the chance of striking objects. Barshot is similar except the balls are smaller and connected by a bar. Because of the tumbling, this is useful primarily at close range. Although, it would certainly cause severe injury or death, grapeshot and canister is better for antipersonnel.
Chainshot at Wikipedia.
Chainshot image: Photograph by Rama - Own work, CC BY-SA 2.0 fr, https://commons.wikimedia.org/w/index.php?curid=6871147
Barshot image: Geni - Photo by User:geni, GFDL, https://commons.wikimedia.org/w/index.php?curid=10790461