Selective breeding for boats

WHY DO BOATS always have to be compromises? That’s the question from a reader in Fort Lauderdale, Florida. “Why can’t designers create boats that are both fast AND seaworthy, sleek AND roomy, strong AND light?” he wants to know.

Well I don’t feel confident about answering that deep philosophical query. All I know is that some things are incompatible. We can’t have day and night at the same time, for instance, We can’t have cat and dog in one pet. We can’t have beer and champagne in one glass. (No, really, we can’t.)

I think the best I can do is to refer my reader to a column I wrote about three years ago, which defines the limits of my rather sketchy comprehension of the subject:

Breeding the perfect boat                                                                              

I CAN’T THINK of anything that mankind has made that resembles a living creature more than a sailboat does. When you stop to look at a beautiful sailboat bobbing gently at anchor in a quiet bay, it’s hard to convince yourself that she’s not alive. It’s not difficult to believe that she has a soul — and is frequently as obstinate and hardheaded as any human being you’ve ever known.

Indeed, the language of the sea indicates how much like human beings boats can be. Sailors have always invested their craft with living characteristics, right from the early days of recorded history, when young girls were sacrificed and their heads placed on the bows of new boats at their launching. This was done to provide the boat with a soul, and the belief was that when the head eventually fell off the bow (usually on the maiden voyage, of course) it was a sign that the gods had accepted the sacrifices and the young girl’s soul had entered the ship. After a few centuries of this, and some rather withering criticism from the fairer sex, men stopped using young girls and substituted figureheads instead.

But the practice of regarding the boat as a living creature continued. Boats are still presumed to be female, at least in English-speaking countries, and designers try to draw them with pretty buttock lines. Boats breast waves and naval boats bear arms. Racers sail on different legs of a course. Hulls have bottoms and ribs, and sails have heads and feet. Blocks have cheeks . . . and so on.

All of which causes one to wonder what boats would be like if they were, indeed, living creatures and therefore by definition capable of reproducing themselves. Could we crossbreed different kinds of boats to make our personal favorites?

I mean, your boat might be good and seaworthy, and she might be really capacious and comfortable below. But she might not perform too well to windward and her sheerline might not win any prizes for aesthetics. What if you bred her with a slim, pretty little performer with a slim waistline?

What would we get if we crossed a Westsail 32 with a 30-Square-Meter, for example? How much would a bug-eyed Flicka be improved by an infusion of gorgeous genes from a Folkboat?

The large variety of dogs that have evolved from the basic wolf have shown us what selective breeding can do. And we can all dream, can’t we? Close your eyes and think about it. What two boats would you like to crossbreed to create your absolute favorite?

Today’s Thought

Life seems to me like a Japanese picture which our imagination does not allow to end with the margin.

— Justice O. W. Holmes.

Tailpiece

“Why did you shoot your wife with a hunting bow and arrow?”

“I didn’t want to wake the kids, Your Honor.”

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

Is there a hump in your sheer?

IF YOU WERE a yacht designer, what do you suppose the most important line in your drawings would be? The bow, perhaps? The stern? The waterline?

Well no, according to some of North America’s best-known designers, it’s the sheer line, the curve of the deck line from bow to stern as you look at it from the side.

Francis S. Kinney, in Skene’s Elements of Yacht Design. calls it “perhaps the one single line that crowns or damns the whole creation.”  Steve Killing, in Yacht Design Explained, calls it “the most prominent and significant line on a hull, It not only defines the character of the boat, but if done well will be (in truth must be) beautiful at any angle.”

And that’s the problem, apparently. When you’re drawing the sheer line by hand, it’s next to impossible to guarantee how it will appear from all angles.  “Sheers that look fine in each individual view can end up having some harsh curves when viewed in three dimensions,” says Killing.

Strangely enough, he claims that sometimes, if you look at a boat from a point off the starboard bow, the sheer can have a hump that appears seemingly out of nowhere about one quarter of the way back from the bow. But, conversely, if you look aft from the same vantage point. the sheer near the transom can appear much too straight.

Luckily, modern designers have found a tool that helps them find the perfect sheer line for any boat — the computer. “Many scoff at the use of computers in yacht design,” Killing adds, “dismissing them as inhuman, permitting none of the art required by the truly talented designer.”  But, in his experience, there is more opportunity for the designer to perfect the look of a boat on the computer screen than there ever was on paper.

A good design software program produces graphics with such speed and accuracy that a designer can now economically run through 10 subtly differing versions of a custom design and do a “walk around” on the screen with particular attention to problem spots that otherwise would have caused surprises and embarrassment on the workshop floor.  It also enables the designer to be sure that his all-important sheer line will always look right, adding beauty and elegance when viewed from any angle.

Today’s Thought

There is no excellent beauty that hath not some strangeness in the proportion.
— Francis Bacon

Tailpiece

A dentist was just finishing up the annual examination of a millionaire Texan oilman.
“Perfect,” said the dentist. “Nothing wrong with your teeth.”
“Well drill anyway,” said the oilman. “I feel lucky today.”

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

The stretch of doom

NAVAL ARCHITECTS ARE DRIVEN MAD by people who want “small changes” made to existing designs.

“Just another three feet in length,” some hopeful says, “and she’d be perfect for me.”

“Just six inches less draft and I’d be able to get across the sandbar.”

I believe yacht designers receive special counseling for this. They’re taught not to pull their hair out, or strangle the potential customer, even if the latter move would improve the human gene pool. They have to explain, as gently as they can, that changes like that mean starting all over from the very beginning.

People who want to build their own boats are especially vexing. Because venturesome sailors have such individual requirements and are usually close to broke, they are often tempted to buy stock plans that a designer has drawn up for a small boat and enlarge them on a photocopier. And when disaster looms, as it will sooner or later, they blame the designer. What they don’t know about is the law of mechanical similitude, a very interesting law that applies to boats of similar shape. Interesting things happen when you alter the size of a boat.

Let’s say you double the size of a vessel evenly all around. Here’s what happens:

— Length, beam and draft increase 2 times.

— Wetted surface area increases by 4 times.

— Interior volume increases by 8 times.

— Weight increases by 8 times.

— Stability increases by 16 times.

Now think about that. The new boat would be 41 per cent faster and could carry four times as much sail. But the point is that even small changes in proportion cause large changes in stability, buoyancy, maneuverability, accommodation, handling, and seaworthiness.

So if you want a boat that’s five feet longer, remember the law of mechanical similitude. Find a boat that was designed from scratch to be five feet longer in the first place. Don’t be tempted to economize with the stretch of doom.

Today’s Thought
Architects are pretty much high-class whores. We can turn down projects the way they can turn down some clients, but we’ve both got to say yes to someone if we want to stay in business.
— Philip Johnson, Esquire Dec 80

Boaters' Rules of Thumb, #158
It’s been established as a rule of thumb over the years that the maximum horizontal pull a person can exert on a line, given a good foothold, is about 150 pounds. If you’re pulling down, then your maximum pull equals your own weight, of course.

Tailpiece
“My neighbor’s dog keeps barking all night. I can’t sleep. I’m at my wits’ end. What can I do?”
“Buy it from him. Then HE won’t be able to sleep.”

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