OPCaTs: 2001 - CMU
This was our junior year independent study. It was me, Alexys Hanczar, David Blackwood, and our advisor Liza Wellman. The acronym stands for: One Person Collapsible and Transportable Sailboat. This project was super fun! Lots of incredible models, cool research, and beach fun. I am continuing to work on the umbrella boat, while David and Alexys are going to work on the accordion. None of the concepts will probably work, but they are cool. We also won a $1000 Surg grant to work on it too. I also got an honorable mention in the Marine Design Resource Alliance competition to design water-craft. Below is the text of my entry:
The OPCaTS project began as an independent study spring of my junior year. Alexys Hanczar, David Blackwood, myself, and our faculty adviser, Liza Wellman all had a strong interest in sailing, and boat building, and wanted to try our hand at boat design. Our goal was to make sailing more accessible to people who had never sailed before, and simpler for those who have. We did not begin with a question, but a desire to make a sailboat that was somehow much more portable than any current solution. Over the course of the semester we did a lot of research, sketching, and debating, trying to fill out the problem more than simply: A Collapsible Boat. There are several existing collapsible boat products, but we wanted something different. We wanted an elegant, cheap solution, which would have a very short learning curve, and would still be enjoyable and challenging once you had learned the basics of sailing.
Our deeper, underlying reasons for this project were to make sailing, one of the oldest free (in terms of energy) forms of transportation more widespread. We found sailing in small light craft to be one of the lowest impact means of transportation. There is no disruption of the landscape, or wildlife and no fuel burned beyond that used to make the craft, which can, with care outlast the user.
With all the positive aspects of sailing, its main drawback is cost. While most people can find access to a body of water suitable for sailing, very few can afford to actually do it. The initial cost of the craft, along with launching facilities, may it be a boat slip, dock, trailer, car, and a place to keep all of this stuff, it is all just too much for someone with a lower income to afford. It can also be daunting to someone who might be able to afford it, but is just getting into sailing. As poor college students living in dorms and apartments, we could all sympathize, and wished to create a solution for urbanites who love to sail. Along with being good for individual consumers, we realized that it would be an ideal solution for summer camps and sailing schools. Instead of needing to waste all that money and effort on facilities, they could get a dozen or so boats, and run their program from a trailer.
With some goals in mind, we set ourselves some constraints, optimistic targets for size, weight, and performance. Originally we wanted something, which was backpack-able for outdoorsy people who might camp and sail, or hike and need a way of getting across a lake instead of spending the day going around it. It was a little extreme, but we decided on less than 30 pounds, no larger than 3 x 2 x 1 , able to carry an adult or 2 children (6 2 175 pounds for the maximum, which is a stretch made because that s what I am.) and have very few parts which are very easy to set up.
Over the course of the semester we brainstormed several ideas, and fleshed them out significantly in order to help find one design to focus on and build. I believe our final three designs were The accordion, a design that could squish from stem to stern into a pancake with a detachable mast, boom, and centerboard, The Umbrella Boat, which is the boat I m presenting here, and The Mutant which was a combination of several ideas and different methods of folding. We chose to pursue the accordion because it seemed the most promising, and had the most traditional hull form. In addition, it was the culmination of all our thinking and best ideas, where as the umbrella boat was my baby from beginning to end. We actually got funding from our schools Small Undergraduate Research program for materials, and started building a full size prototype, but as summer approached, our thoughts changed from boatbuilding to swimming, barbecues, and goofing off. It was eventually decided that if any work was to continue on the boat, Lex and Dave would finish up the accordion and I would do the umbrella boat.
I have had the concept and some of the basic parts designed for some time, and it just took several intense sketching sessions to get it all down on paper, and a couple of days in front of a computer to get it into my favorite CAD program, SolidWorks. The finished product is a computer model of all the parts needed to construct my umbrella boat. In addition to designing parts, you can also put them together and see them work as one complex object, so I have proof that the physical interaction of the parts works. The renderings, which precede this paper, were all generated with this program as well.
How It Works:
The boat is based on an umbrella, where the stem of the umbrella is the mast, just like in the icon on the front page. While this is an interesting idea, it is impractical, otherwise you d have either a very small sailboat, or a very large folded package to carry around, so a compromise was in order. After studying different kinds of umbrellas, I chose to use the three-segment system found in some smaller umbrellas. Setting three feet as the longest a segment could be, I was able to construct a roughly boat shaped hull, with the stem/ mast in the right place by varying the proportions of the members. One of the only things I was not able to model was how the members would bend as it opened and the waterproof canvas would pull the tips in and up. The result of this inaccuracy in modeling is a very shallow boat, around nine inches, where it should be more like eighteen to twenty four. The only other modeling inaccuracy is the top skin of the umbrella. In order to not sink immediately after heeling a few degrees, I decided to have the umbrella more like a bag, not a shell. The space between the outer hull and the top bag would be all buoyancy, where the user would sit on the top bag, which is stretched over the mechanism, from gunwale to gunwale. The umbrella hull is opened by pulling on, and cleating a line, which pulls the two hubs of the umbrella together.
Mast and sail:
The mast, which is essentially the stem of the umbrella, is comprised of five telescoping aluminum tubes, each less than three feet long. The boom uses the same system (three tubes), but with an additional element, which allows it to hinge down where the boom meets the mast, and rotate when the boat tacks and jibes. The telescoping sections are held in position by spring detents when open. With the sail permanently attached at the tip of each section, they cannot pull out any further than needed, saving weight and expense for a different solution. The main sheet attaches at the end of the middle segment, and at the top knuckle of the keel umbrella segment.
Centerboard and rudder:
The centerboard is comprised of a hinge and board cantilevered off the bottom hub. The centerboard rotates up when the boat is folded away, and a large spring detent pulls back when unfolding it, so when the boat is open, the centerboard can t close up through the canvas hull. While this was enough to qualify as a working sailboat, I wanted to make it adjustable for more advanced users. The way I solved this was by having two lines attached to the centerboard, around the hinge point. The one on top pulls it up, and the one on the bottom pulls it down and forward. These lines go around two pulleys in the front, metal section of the centerboard, and up a sealed tube in the stem. The lines come out at the top and are cleated off at the desired position. The tube that the lines travel in is sealed, but it is filled with water. Since it would be difficult and prohibitively expensive to seal it around the centerboard hinge joint, I decided that as long as the hull canvas was intact around the hole at the bottom, I could have a hole in my boat like a hole in a donut and it would still float, just like a very small centerboard trunk. The Rudder is hinged to the keel segment both to turn and to fold against that segment when the boat is folded up. The tiller is simply hinged at the back of the rudder, so when folded up, it lies on the back of the rudder.
1. Pull the centerboard detent, and fold down the centerboard to its full up position.
2. Open the hull by first working it out by hand, and pulling on the line to pull it to it s final opened position and tension.
3. Pull out the mast and boom, keeping sure that the sail is not twisted around either.
4. Fold out the rudder, and flip up the tiller.
Open hull: 9.5 x 4 x 1.5
Keel to top of mast: 14 feet
Sail: 10 feet by 6.5 feet with an area of 32.5 square feet
Closed package: 34 x 18 x 50
Weight: 24 kg (Plus the weight of the waterproof skin, sail, and lines. 6kg?)
Cost: less than $1000
While my solution exceeds some of our initial goals, I believe it is still a practical, workable solution to making sailing more accessible to everyone. It would be prefect for camps and sailing schools, people who live in the city, but still want to sail, and college kids, who don t have the space to keep all that junk. It would not change the world, and you sure wouldn't want to lug it on your back through the forest, but maybe some guy working in Boston will go for a sail on his lunch break, or maybe some kids will learn how you can go really fast without burning anything. Making the actual artifact of sailing more compact, and easier to use, will open up whole new groups of people who might never have been exposed to it.