Keel 14 : The principal structural member of a ship, running fore and aft on the centerline, extending from bow to stern, forming the backbone of the vessel to which the frames are attached
NFPA 1405 Guide for Land-Based Fire Fighters Who Respond to Marine Vessel Fires, 2001 ed. http://www.nfpa.org/assets/files/AboutTheCodes/140 5/1405-F2005-ROP.pdf, (Guide: Land-Based Fr Fightr Who Respond to Mrn Vssl - Amer) {396 NFC}