Definition
Noun
- The movable fin aft on a vessel that allows it to turn.
Origin
5th century. An earlier term was rother, which was the steering oar. The earliest English word was from the Old English word roper, which came from the Old Norse word roder, meaning steering oar.
Comments
The first rudders appeared in the mid-12th century. The rudder is moved left or right by the helm of a vessel, and since it is beneath the waterline, the resulting water pressure causes a change in course. The same principle in mechanics is that every action has an equal and opposite reaction. The rudder deflects water in the direction it’s turned, and the reaction forces the ship’s stern in the other direction. Thus, the ship’s head moves in the same direction the rudder is turned.
References
Kemp, P. (1994). The Oxford Companion to Ships and the Sea. Oxford University Press.
King, D., Hattendorf, J.B, & Estes, J.W. (1997). A Sea of Words: A Lexicon and Companion for Patrick O’Brian’s Seafaring Tales (2nd Ed.). Owl Books.
Rogers, J.G. (1985). Origins of Sea Terms. Mystic Seaport.
