Thursday, January 26, 2012
Tools of the Trade: Point Her Rudder
The rudder of a ship is, it goes without saying to the Brethren, the piece that directs her. Sizeable ships, usually of brig size or larger, worked their rudders through the use of a series of cables connected to a wheel. The famous picture of a ship’s gleaming wooden and brass wheel is iconic, but the icon in and of itself is often mistaken. Smaller vessels such as sloops, schooners and pirogues – those favored by pirates, privateers and smugglers – controlled their rudder through the use of the more straight forward tiller.
Dana’s take on the workings of a ship’s rudder is so pure in its description and no-nonsense in its language that my paraphrasing it would be criminal. Besides which, I can wrap my head around how a rudder works and use one without going astray but the intricacies of steering a sailing ship can be difficult to put on paper. Unless you happen to be a genius at such things, as Dana surely was. Here then, from Chapter 10 “General Principles of Working a Ship” in The Seaman’s Friend, a few paragraphs on the all important rudder:
A ship is acted upon principally by the rudder and sails. When the rudder is fore-and-aft, that is, on a line with the keel, the water runs by it, and it has no effect upon the ship’s direction. When it is changed from a right line to one side or the other, the water strikes against it, and forces the stern in an opposite direction. For instance, if the helm is put to the starboard, the rudder is put off the line of the keel, to port. This sends the stern off to starboard and, of course, the ship turning on her centre of gravity, her head goes in an opposite direction, to port. If the helm is put to port, the reverse will follow, and the ship’s head will turn off her course to starboard. Therefore the helm is always put in the opposite direction from that in which the ship’s head is to be moved.
Moving the rudder from a right line has the effect of deadening a ship’s way more or less, according as it is put at a greater or less angle with the keel. A ship should therefore be so balanced by her sails that a slight change of her helm may answer the purpose.
If a vessel is going astern, and the rudder is turned off from the line of the keel, the water, striking against the back of the rudder, pushes the stern off in the same direction in which the rudder is turned. For instance, if sternway is on her, and the helm is put to the starboard, the rudder turns to port, the water forces the stern in the same direction, and the ship’s head goes off to starboard. Therefore, when sternway is on the vessel, put the helm in the same direction in which the head is to be turned.
A current or tide running astern, that is when the ship’s head is toward it, will have the same effect on the rudder as if the ship were going ahead; and when it runs forward, it will be the same as thought the ship were going astern.
Sternway is, of course, the opposite of headway; an action whereby the ship is moving backwards instead of forwards. Thus the need to change the way in which the rudder is handled.
If you’ve an interest in Dana’s comprehensive work, The Seaman’s Friend is available online at the California Digital Library and in plain old cover-to-cover book form from Dover Publications.
Header: Cover of the 1997 addition of Richard Henry Dana Jr.’s The Seaman’s Friend