The evolution of steering

WHAT WOULD YOU SAY is the most unappreciated part of a sailboat, the one thing that’s invariably overlooked and neglected, but without which the boat simply cannot function? Yes, that’s right, it’s not the skipper. It’s the rudder.

On larger boats it’s out of sight (apart from the few stern-hung rudders still around) and it’s largely out of mind. It’s a truly modest and uncomplaining piece of equipment, one that doesn’t need to be fed constantly with expensive diesel fuel, one that never goes flat and needs charging, one that never has to be taken to the sewage pump-out every week, or varnished every six months.

It is a marvel of efficiency; and also such a marvel of simplicity that you have to wonder why it took so many hundreds of years to make an appearance on sea-going ships.

The ancient Phoenicians, the Romans, and even the Vikings, used steering boards — oars or paddles, usually hung from the right-hand quarter. (Hence the starboard — steerboard — side. The other side was the side that rested against the port, so the steerboard wouldn’t be damaged.)

It wasn’t until 1242 A.D. that pictorial evidence appeared of a centerline rudder on a ship in Europe. It was, if you’ll forgive me, a turning point in marine design. Apparently this new-fangled invention was received with such enthusiasm that it was quickly adopted by shipbuilders all over the world. Pintles and gudgeons suddenly became household words.

How does the rudder work? Well, in the crudest of terms, if you push it to one side, the water flowing past strikes that side with more force than it strikes the other, so the rudder tends to be pushed sideways, taking the stern with it. (It is actually a foil whose shape provides “lift” like an airplane wing does, but never mind that for the moment.)

I often marvel at the way a tiny rudder can turn a 250,000-ton oil tanker; although, lurking in the back of my mind somewhere is something vague I once read about the rudder only initiating the turn, and the ship’s hull itself acting to reinforce the turning moment, as might a wedge driven through the water.

It’s interesting to note that the average sailboat rudder will stall and lose efficiency if it is put over more than 35 degrees from dead ahead. In fact, it will act as a good brake if you are approaching a dock too fast and you can put it over to 90 degrees, first one side and then the other.

While most rudders lurk quietly and invisibly beneath their mother ships, the importance of their roles has not been lost on naval architects, physicists, and engineers. The design and performance of rudders is the subject of countless scientific papers and even whole books. In this respect, if you should wish to develop your latent rudder fetish, get hold of a book called The Development of the Rudder, by Lawrence V. Mott. It’s a fascinating and lavishly illustrated volume of nautical archaeology that digs deep into the conception of the modern rudder, starting with its crude but rather interesting parents in various parts of the world.

Even if you don’t find yourself entirely enthralled by rudders, it will help while away large parts of the long, bleak period between the morning cocktail and the evening sundowner.

Today’s Thought

The ancient sailor said this to Neptune in a great storm, “O God, thou shalt save me if thou please, if not, thou shalt lose me; yet will I keep my rudder true.”

— Montaigne, Essays

Tailpiece

“And you, madam, what’s your husband’s average income?”

“Oh, usually well after midnight.”

(Drop by Monday, Wednesday, Friday for another Mainly about Boats column.)

Taking a strange turn

THE OTHER DAY I was reading a book about boating for beginners. The author went to great pains to explain the difference between the way a boat turns and the way a car turns.

He pointed out that a car is steered by its front wheels, and pivots around the rear wheels. A boat, on the other hand, is steered by its rear end and pivots around its front end. Or near enough. What this means is that when you turn a corner in a boat, your rear end swings out and hits the jetty or any other boats nearby.

This might seem a trifle strange to neophyte boaters who, seeing a steering wheel in the cockpit of a sailboat, might be forgiven for presuming that turning it would produce the same physical actions that you get in a road vehicle.

But what interested me more was thinking about how people turn. You don’t have a steering wheel or a tiller. You don’t have wheels or a rudder. So what makes you turn when you want to? I think it has something to do with the brain. At least, that’s where the orders come from. But that doesn’t explain the physical act of turning. Do people steer themselves more like cars, or like boats?

Experimenting in my socks on the vinyl floor in the kitchen, I discovered that my upper body initiated the turn. After I turned my trunk to the left, my legs seemed to follow. But I didn’t pivot on the left foot, as I thought I might. I just sort of shuffled, left foot, right foot, and then I was going off in a new direction.

That didn’t tell me much. I thought of asking my wife to take part in my experiment. I wanted to see if her stern swung out to starboard when she changed course to port, but I thought better of it.  She already suspects that my elevator doesn’t go all the way to the top.

I couldn’t see whether my own stern swung out or not, but I think not, because I missed the fridge and cleared the pantry door quite nicely. Of course, I don’t have a particularly prominent stern (and neither does my wife, I add hastily) so it’s really hard to tell, but my feeling is that humans steer more like cars.  In other words, we probably have imaginary steering wheels that somehow make our feet turn.

I wish someone would initiate a study to find out how this all works. Nobody seems to care about how we turn. Most of us just take it for granted. When we want to turn, we just turn. We don’t do anything about it. Mostly we don’t even think about it. We just turn.

Try it for yourself. Watch your feet as you make a turn. If you can figure out how we do it, let me know. No steering wheel, no tiller. How is it possible? It seems like black magic to me.

Today’s Thought

Fortune once in the course of our life doth put into our hands the offer of a good turn.

— Sir Geoffrey Fenton, Bandello

Tailpiece

Groucho Marx once opened a drawer by mistake in a friend’s home. He found a Colt automatic pistol surrounded by several small pearl-handled revolvers.

“My God,” he said, “This gat has had gittens.”

(Drop by every Monday, Wednesday, Friday for a new Mainly about Boats column.)

Go gently on the helm

IT’S OFTEN SAID that anyone able to handle a sailing dinghy well ought to be able to steer a much bigger boat with equal ability, whereas the reverse is not the case. But this idea is pooh-poohed by Douglas Phillips-Birt, the renowned British designer and author in his book Reflections on Yachts (Nautical Publishing Company).

He says the chief feature of the modern dinghy is her extreme lightness.  She loses way in a moment and picks it up again equally quickly. “She can only be handled by rapid and considerable helm movements capable of putting her about before a sea stops her, or of keeping her moving by a process of weaving through seas which she lacks the power to trample down.”

But that situation is reversed in a bigger, ballasted yacht, says the author. “The most effective way of applying the brake is to swing the yacht abruptly from one course to another.”

Why should this be? Well, think about what happens when you turn the rudder. “The fact that the rudder is put over to a certain angle when altering course creates a little resistance, but that of the rudder alone is a trifle. The effect of the rudder is to give the whole hull a sheer or angle of yaw — it is analogous to the angle of leeway when sailing to windward. The whole yacht, in fact, starts moving obliquely. The water pressure set up on the hull thereby, and not the rudder, is what ultimately turns the yacht.”

It’s obvious that this sideslipping through the water must entail a large increase in resistance to forward movement.  Phillips-Birt estimates it’s something like an additional 10 percent for each degree of yaw established.

“So, when a few spokes of the wheel are applied, the head swings this way or that only because the hull has first been set into an oblique manner of advance, which is very much more resistful than advance straight ahead.

“You pay a great deal in added resistance for a few degrees of luffing up or bearing away.”

Every time the helm is moved, he adds— easy though the movement may seem, and harmless — it initiates a train of events introducing far bigger forces than those applied by the helmsman, and these tend to stop the ship. “The best helmsman,” he concludes, “is the one who does not seem to be steering.”

Today’s Thought

We spend our lives in learning pilotage,
And grow good steersmen when the vessel’s crank!
— George Meredith, The Wisdom of Eld

Tailpiece

“The tolerances in this engine are very fine ­— we aim at no more than three thousands of an inch.”
“Wow! How many thousands are there in an inch?”
“Gee, feller, I dunno. There must be millions of them.”

(Drop by every Monday, Wednesday, Friday for a new Mainly about Boats column.)