strongback

Noun

 * 1)  The fore-and-aft spar extending from stem to stern on a lifeboat and serving as a raised spreader for a boat cover. (FM 55-501)
 * 2)  A strong bar placed across a hatch opening to hold hatch boards or hatch covers. (FM 55-501)
 * 3)  A load-bearing post with a T-shaped cross-section, where the short T-tail prevents bowing of the long post.
 * 4)  A backing pole used to reinforce and stabilize vertically-oriented sculptures.
 * 5)  A vertical structure used to support and stabilize a rocket, often hosting fuel and power umbilical connections. Usually retracted immediately before launch.