The first thing you'll notice about our designs is that they come out of direct experimentation on the water, instead of calculated formulae or computer extrapolations. We tried all that and found it didn't cut it when it came to creating boats that really, really perform. Let us explain. We came to boating directly from surfing. We noticed that the more we surfed, the more we could predict the performance of a particular surfboard by just looking at it. We found were slowly learning to recognise good shapes and bad by trying many different kinds of boards. Surfboard shapers like Dale Velzy would let us try experimental new boards they'd created and then debriefed us after each session on how the boards performed.
Later in Hawaii, I found myself without a board of my own so some sympathetic Islanders in the apartment next door would make sure there was a fresh board lying outside the door every morning. Everything from pintailed big-wave guns to stubby 7-11 hotdoggers. It was only later that I found out that they got the wide variety of boards from their "cousins" who worked at the airport, where the boards would "go missing" for a few days, while we all tried them out.
The next step in our education was to follow the lead of the quiet
revolutionary, Hobie Alter, who was making the transition from
being one of the Coast's largest board-builders to becoming the
world's most prolific sailboat producer with his ubiquitous Hobie-Cat.
We had a chance to try out his early wood prototype of the Hobie
14 and then found ourselves designing a prototype landsailer for
him as a product experiment. Through this project we were able
to enjoy afternoons of listening to his design theories, which
we found to be both inspiring, and accurate. For instance, his
approach to structural integrity would make Ralph Nader's hair
uncurl; -but it worked. His theory was that a truly good design
should "all come apart at once, when it breaks. You shouldn't
be able to find a piece bigger than a potato chip after it all
comes apart."
We found he was right. If you make one part too strong, it loads
up the parts around it. Everything must have a little give, and
the amount of give should be tuned to blend with the parts around
it like an organism. Otherwise you'll either end up with a weak
point caused by a too-strong point next to it; -or if it's all
too strong, it'll weigh too much to perform well. We think the
guy is a genius for creating performance on the water. But nevertheless,
we turned our back on his approach when we built our first 24'
catamaran, -and went blindly to the "design gurus of yore"
to get formulae we could follow. "The immersed rudder area
shall be 1/12 the profile wetted surface." "The center
of effort shall be arrived at by bisecting the sail corner angles
and lofting the meeting point." and on and on through the
mystiques of prismatic coefficients. Stuff that sounded good on
paper, but in actual tests, had little to do with what the water
wanted the boat to be.
What we learned from these formulae was that after all that effort,
our boat wouldn't sail worth a damn. Every formula-derived component
had to be ditched or radically revised before the boat would perform
under control. When we learned that a particularly balky-to-steer
name-brand 55-footer that we crewed on had to have its rudder
moved to make it controllable downwind, we were beginning to lose
faith in formulae and gurus. After all the sister boats of this
55-footer were changed at great expense (and they still didn't
steer worth a damn), we abandoned the gurus, and went back to
Hobie's approach: built it to look right to your instincts, try
it, if it doesn't work just right, change it until it does; -and
then paint and varnish it when you know it works the way you want
it to.
Designers will sneer at this approach because it admittedly is
a less expert approach. If we had magic genius we could all simply
draw a great-sailing boat onto paper and build it. But when you
sail many boats on the market, however, you'll find that the designers
probably should have resorted to this cruder approach, and produced
a better-sailing boat. To look more accomplished, they're skipping
some essential steps, and the results are not always nice to sail.
When we build a new boat, it's sailed at the earliest moment it
can hit the water. The more time and effort you put into finishing
a part, the less you'll want to change it later, even if it doesn't
work. When the Weekender hit the water, it had only one quick
coat of paint on bare wood to keep it from being damaged. We've
even sailed bare-wood boats to keep us ready to junk everything
and start all over if the design doesn't work on water. Designing
solely on paper can be a trap. I know I'm a pretty good pedal-car
designer, after having done a bunch for national magazines. I
put out pretty cute bodies, and I feel confident in my abilities
to repeat the process.
When I did a little MG-TC, I felt I was getting so good that I
could simply draw the dimensions out in two dimensions and have
it look right. But as it turned out, I had to start all over and
go back to the more effective way of creating three-dimensional
objects, -simply by sculpting them in plywood full scale. It's
a cruder approach, but when you put designs sculpted in full-scale
next to paper-designed designs, the difference is obvious. The
Italian sportscar designers worked directly on the finished chassis
in the materials that would form the final car. The results are
priceless museum pieces now. Meanwhile Ford was designing the
Edsel with one of those new computer things. Computers make for
designs that look good on a screen, but may look different in
real life, -and outside. The Jag xk-120 was designed outside in
the lighting and perspectives that it would be seen throughout
most of its existence. After a while of studying design, you get
where it's fairly easy to spot which cars were designed indoors
and which were crafted outdoors.
Boats are a little different from cars in that their shapes not
only set their look, but also their performance through the fluid
media of the air/water interface (the billowy waves). So we try
to create a design situation that keeps everything as fluid and
changeable as possible through tests. Once we know how it should
be to work right, we get out the sandpaper and paint.
Even then, we can get fooled. When we built the first Weekender,
it was an extrapolation of a very successful earlier, smaller
design, the Skipjack. This boat came about when we spotted a small
plastic model of a Chesapeake Bay Skipjack and saw how easy it
would be to build a small one out of plywood. The boat sat nose-down
in the water when we first floated it with no one in it. But then
we tried sailing it (unpainted), and found it went like a witch
(and when someone was sailing it, it sat just right in the water).
To digress even more, one reason the Skipjack went so well was
its light weight (I could easily sling it on top the car by myself
even though it sat four). And the reason it was light goes back
to a still earlier design, the Caliban. This was a little 16-foot
double-ended Greek fishboat replica out of plywood called a Caicque.
When we built this boat for "Boating" magazine, we first
made up a little cardboard model to set the panel shapes. First,
we cut out a keelson with stem and stern posts. Then we cut out
a bottom panel and taped it to the cardboard keelson. Then we
cut out hull sides and taped these to the bottom panel and the
stem and stern posts. The model felt like all cardboard models;
-floppy and flexible when twisted longitudinally.
But when we cut out the peripheral deck panel that extends all
around the sides, front and rear, and pushed in down inside the
hull sides, the model suddenly changed. It became incredibly rigid
and resisted all twisting. Not only that, but we noticed that
if you simply lined up the centerlines of all the parts as you
assembled them, the boat came out exactly straight and true with
no need to realign it. We knew we were onto a new kind of boatbuilding.
When you have a structure that's naturally very rigid, then you
can use much lighter parts and still have a nice, strong boat.
When you have a naturally strong boat, you don't need much framing.
All our boats at Stevenson Projects are really variations of this
first Caicque. Sometimes we lop off the rear and put on a transom
(which doesn't really change the structure of two tetrahedrons
joined base-to-base). -Sometimes we slant the bow forward, sometimes
we stick on a cabin. But the boat structures are all the same
basic shape. -The double tetrahedron, with all the panels bent,
-and then stressed in sheer against this bend. When plywood is
stressed this way, it's stronger than steel pound for pound.
So that's why we don't need much inner framing. That's why we
use 1/4" ply and get away with it (after some really hair-raising
true-life tests), and that's why we don't have to use expensive
jigs to hold things aligned. The fewer the framing parts, the
lighter the boat, the cheaper the boat, and the faster sailing
(except in heavy weather chop) the boat.
Since all boats are design trade-offs, we went with light-weight
because it's nicest to trailer, and nicest to sail in almost all
day-sailing conditions. A heavy boat will plunge on through a
very heavy chop head-on better than a light boat. But we can always
add ballast if we need to punch through steady chop conditions.
A light boat can also stay afloat if you dump it, while ballast
will drag the boat down. But dumping a Weekender isn't as easy
as some boats.
The whole approach of the Weekender can be traced back to the
workboats of the last days of sail at the end of the 1800's. These
boats used low-center-of-effort rigs and shallow keelsons. And,
as the yacht "America" that came directly out of fishboat
design proved, it still works well, creating a very fast, sea-worthy
machine. It was only at the advent of special-condition, special-rules
racing yachts, that sails reached up to the skies and keels had
to reach down to the depths. Clipper ships had tall masts, of
course, but seen in profile, the whole ships had low rigs in proportion
to their length. And very shallow keels. Yet they held speed records
until recent special racing machines finally could beat them.
When you try to capsize a Weekender (as we did, just to see what
would happen), you're in for some surprises. We went out in a
really stiff breeze, hauled all the way in on the sheets, sat
on the wrong side and held on. The mast arced down toward the
water as the hull tipped. But then the Weekender acts a little
differently than most we've sailed. The hull is light enough to
float on its side decks as the cabin windows splash against the
waves. It can sail all day on the side decks without getting water
into the cockpit. Meanwhile the sails are becoming shaded by the
hull running along on its side decks. We never could get the thing
to go all the way over. It just skimmed along on its side until
we got tired of clinging on. With hurricane winds, of course,
the hull bottom, sticking up in the wind will get blown over,
and the rig will dig in into the waves. But in those winds, the
Weekender won't be the only boat in trouble. Overall, it's pretty
hard to capsize!
Getting back to the mistakes you can make designing boats, we
made a mistake with the first Weekender that wasn't corrected
until we got word from a Weekender builder that made us take the
boat out for a whole new kind of test.
This mistake came out of the fact that we learned early on: that
the smaller the boat, the more exact the balance between sail-force
and hull force must be. With a 10-footer like the 3-In-1, we not
only worked hard to get the centerboard position right on the
button, but we also used proportionally larger control surfaces
than we would with a larger boat. Look at the rudder of a clipper
ship. It's tiny, compared to the profile of the hull; -while a
small sailing model boat uses rudders and keels that are far larger
than the full-scale version.
Small-boat sailing is actually more precise than large yacht
sailing (as is proved every time when a yacht skipper who's never
sailed a dinghy ends up in the drink when he tries to sail one,
-while a dinghy-sailor will do fine skippering a yacht for the
first time).
As we increased the size of the original Skipjack with the Weekender,
we forgot this scale-effect. The larger Weekender not only had
a pretty big keelson, but it was also a good proportion bigger
than the Skipjack. Without realising it, we'd made a boat that
no longer needed a centerboard.
It wasn't until that builder wrote to tell us that he'd gotten
sick of fiddling with the weekender centerboard, which was a pain
to get on the trailer right. He ripped it out and went sailing
without it and said the boat sailed just as well, except for working
to windward in light airs. But then, he said, if you sat on the
down-wind side of the cockpit to induce the same sort of angle
of heel that you'd have in a breeze, the boat takes off like it
should.
We tried it, and he was right on all points. Not only that, but
we learned a few new points about the weekender design. We knew
from experience that the boat could work its way up a channel
to windward with the best yachts in the harbor. But we also knew
that when we tried to hold the same angle to the wind as a keel-yacht,
we simply couldn't do it. The boat just wouldn't "point"
with a yacht, yet it always seemed to make a windward point just
as well as a keelboat.
On closer look, we began to understand why. The Weekender sails
to windward well when we keep it tipped so the hull chine is down
in the water, biting well. This pushes the hull sideways to windward
so it "crabs" its way upwind. Since it seems to keep
up good speed and makes the windward point, we don't complain
that the angle of the boat to the wind isn't as close as a keelboat.
As long as it makes that windward point, that's all that counts.
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