by Bob Dill (December 1984)
| Ever since I started ice boating, I have never liked sailing with a
rigidly mounted tiller waiting to knock my teeth out or worse if the boat stopped
suddenly. Last year I finally figured out a way to make a releasing tiller and sailed with
one all last season. Although I never got an opportunity to test it by being pitched out
of the boat, I did not have any problems with the tiller other than leaving it home on one
very fine sailing day. The design involves a short stub tiller with a clamp mounted on it (see drawing 1 and drawing 2). The long part of the tiller has a Delrin slide bolted to the bottom of the front end. This slides back into the clamp and is held in place by a plastic shear pin which passes through the main and stub tiller in two places. From my experience a release force of about 100 pounds is necessary to prevent premature releases. The nose of the slide is offset so that it will kick the tiller to one side when it hits the ratchet block mount. A pair of Delrin wedges are bolted to the side of the tiller to kick the tiller up and out of the clamp as soon as the slide is free of the clamp. Round and smooth edges and corners to make things slide by each other easily. When making the clamp, it should fit closely to the slide so that there is no slop but so that it can still slide forward relatively easily. I used shim stock for final adjustment. Although I have not shown fasteners in the drawings, I used No. 10 and 1/4" bolts to hold things together. the attached drawing shows important details of the design. The current design has plenty of room for improvement. If you would like a lifetime supply of shear pins (designed to shear at 50 pounds), send me a self-addressed, stamped envelope. Once in a while, people do get teeth knocked-out or even impaled on tillers in crashes. After several years of sailing with a push out tiller I am more convinced than ever that they are a good idea. Fortunately, I have not had the misfortune of testing its effectiveness. The design has evolved some but the concept remains the same. The tiller is simple. It is made in two parts: a short stub tiller connected to the shoring post and the main tiller. The stub tiller has a simple clamp. The main tiller has a slide bolted to it's bottom. The slide fits closely into the clamp. The clamp restrains all movement of the slide except forward. Sideways movement is most important and requires a very close fit. The slide has an offset nose to kick the tiller sideways when it hits the steering post ratchet block (or a kick out block). To keep the slide and tiller from sliding forward during normal sailing a shear pin or two is placed in a small holes that run vertically through the stub tiller and the slide. In a crash, you may be thrown forward into the tiller. The impact quickly exceeds the 100 lb force necessary to shear the pins. The tiller is now free to move forward. After moving forward a couple inches it is free of the clamp but is about to run square into the tiller post and ratchet block. The slide nose is offset to one side so that when it hits the steering post the front of the tiller will be pushed to the side, and be completely free of the boat. With the original design shown here, a kick out wedge is necessary on the main tiller. This prevents the main tiller from getting captured laterally in the clamp after the slide is pushed forward. The wedge lifts the tiller as soon as the slide is clear of the clamp. The second design does not have this problem. The current version has an aluminum stub tiller and slide, along with a Gougeon style sliding tiller. The tiller makes a good slide hammer. I added a simple impact absorbing device in the tiller tube (a stick and a nylon string). I am working on a new set of drawings. They are included in their partially completed state. This tiller design is simple and can be made a bunch of different ways. Make your own design. If you want some suggestions (or some shear pins) give me a call. |
