Dictionary of Ichthyology  

outrigger = 1) a long and thin float attached to a vessel, such as a canoe, by projecting spars. This serves to prevent capsizing. Also refers to any vessel fitted with such a float.... more

Filipino fishing boats with outriggers, Wikimedia Commons: http://commons.wikimedia.org/wiki/File:Filipino_fishing_boats_with_outriggers.jpg

Canadian Museum of Nature