Tim: Good looking job on the rudders!
If the holes in the laminated tiller are just drilled into the wood, it's no great surprise they would stress it out and split. Try drilling the holes out oversize and backfill with thickened epoxy. If the bolts are maybe 5/16's, I'd make the hole at least 5/8" or even 3/4". Put blue masking tape on one side, and pour into the other. Leave the pour a little proud to allow for shrinkage and sand it down flush when it cures. The tape side will already be flush. Once the thickened (wood flour for color and fumed silica - not thick enough to hold shape, but thick) epoxy sets up, drill out the holes for the bolts. The stress will all be on the epoxy bushing and not on the tiller....and it won't rot. BTW, a lamination made with epoxy cannot be tightly clamped. If you are going to do that, use glue...preferably resorcinol. Tightly clamped epoxy joints don't have much strength. But with some gap in the joint, epoxy is probably stronger than anything, but if finished bright, has to have several coats of varnish to avoid UV degradation of the epoxy. To make curved laminations with epoxy, you have to clamp it tight to take the curve, so I use something in the epoxy as a gap spacer to prevent squeeze out. The something I prefer is 30/100 sized walnut shell. Very fine sand might also work, but will play hell with any planes or sanders you use to sand the tiller smooth. Probably better to use resorcinol in the first place. On Aug 9, 2008, at 10:10 AM, Tim Diebert wrote: > > "While the M17 rudder does raise and lower, even when the rudder is all > the way up, it's the first part of the boat to "find land". If the Bay > was home a kick up rudder might be nice. The M15's come that way. Short > of making your own (doable), Ida Sailer might be the way to go." > > This made me chuckle. I made a nice new rudder last winter > and although I had never touched on my 17....the first sail with the > new > rudder and I did exactly that. DOAH!! > > ...at least it was just sand and a few small rocks. > > http://www.timtone.com/monty/rudder.htm > > > The rudder on my previous boat was hinged and worked very well. > I would have no reservations about having one again, but for the M17 I > took > the easy way out and made a one piece unit instead. > This might give you some ideas if you were going to make a lifting > version. > > http://www.timtone.com/tt/ttphotos/images/RudderStockandRudder.jpg > > > As for tillers, I have made many. I always thought the laminating > order was > right and wrong at the same time. It makes sense for the laminates to > be > horizontal > in order to follow the form or shape of the tiller. But in terms of > strength, the holes > to attach the tiller to the rudder are usually horizontal....and this > is a > good place for > any degradation to start. With horizontal laminations and horizontal > holes > it is not a > great combination in that regard. > Having your laminates stacked so the glue lines are vertical makes more > sense to me, > but then you have the force that is exerted on the tiller during use > that is > against the > more vulnerable lamination. Around and around we go. > On bigger tillers I have done a taper laminated style, with horizontal > laminates, but set > a few recessed through-bolts vertically through the laminates as a > back up. > > > Cheers, Tim. > > > > > > > _______________________________________________ > http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats > _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
