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
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.