Wow! That's a wonderful response! Thanks guys! Here's more in hopes of answering questions and or clarifying things. The current booom started life as a 2" hand laid fiberglass tube. Malcom immediately (after sailing it the 1st time), wrapped most of it with layer of Divinycell and another layer(s) of glass. The day the wingmast snapped (another story) I noticed the boom flexing to leward enough to cause concern, it was a 15 kt day, max. Part of trying to analyze why the mast broke where it did, Malcom and I figured it couldn't hurt to take the compression force off the mast and transfer them to the main crossbeam, which I'm pleased we did. By dropping the boom down to the crossbeam, it needed 14" of additional length to have the outhaul work properly. Bogged up a very stiff, thick walled, 8' carbon pole and slid it inside. This did actually stop the flexing really, but at the end of the season I could see stress cracks in the paint in the area just beyond where the 8' tube stopped. So some signs of weakness, the wrong angle for the mainsheet traveller, and excess weight brought me to thoughts of a new boom. Seems not everyone is catching the concept of the underside traveller for the mainsheet, which I like the theory of, and will try to relate as clearly as I can manage. Here's how Malcom, the boat's designer and builder, described what he was after. His main goal was to be able to use the main traveller to spill power in the gusts, which allows the main to retain it's shape, w/tight leach, not twist off and spill air. He claims that with skilled crew running the traveller (4 to 1 purchase, continuous sheet), he could keep the boat on it's feet, accelerating in the puffs, not losing energy by heeling excessively or allowing the power to spill out of the main with too much leech twist (associated with the rise of the boom) when you dump the mainsheet. By dumping the main traveller instead of the mainsheet, with the underside traveller on the boom, the aft end of the boom swings to leward without rising (leech twist, spilling). The pull downward on the boom (and clew) is always perfectly vertical and constant regardless of how far sheeted out, neither adding nor subtracting from the boom compression. So the theory sounds nice, but I can't say that I've been able to test it much, as I mostly sail the boat solo or with unskilled crew. And I don't yet trust the traveller as much as I do the mainsheet in a panic dump. It's still a new and somewhat intimidating boat when fully powered up, and I'm trying real hard to keep it upright , at least until I have a more comprehensive plan to right it than I do at this time. John and others, good eye! Sorry for the sloppy rigging! I just threw the main up the day I pulled the boat, so I could take the picture to try to have a chance at determining the angle between the underside traveller and the top edge of the boom. The lowest sail slide isn't even in the track! I normally lash the tack directly to the mast when sailing. Thanks for suggestions on pole diameters and sources, I will pursue those options too, though cost is, unfortunately, and issue. Anyone else have thoughts on triangular sections? Wouter, you once again are very generous with your thoughts, though I don't have a real clear picture of the design you're offering. Simple sketch maybe? Seems like the T concept I offered shares the intent of maximizing material where it's most needed. Keith, your right in that I don't need any of the properties you mentioned, the endplate effect, sail storage platform, and ? . But it does seem to offer substantial resistance to flexing out of column, in both directions, with a minimum of weight, and within my modest skills. I don't like the windage either though. The design does allow easy accomodation of the underside traveller. Please keep the comments coming, I'm far from decided on the best course of action here.
The boat was built 5 or 6 years ago by Malcom Davy, Downunder Boatworks, Kelseyville, CA, a boat restorer who built it for himself, as a challenge and a project I think. It's 24' x 14', maybe 750 to 800 lbs now, between Malcoms early modifications and additions, an my repairs and reinforcements (ongoing this winter), cylinder moulded, canted hulls, assymetrical daggerboards (very effective!), sweet rudder system, 36' Barlowe design, Gougeon Bros technique, wood/epoxy (and now carbon uni) wingmast, and waycool central pod system for storage. I drug the boat home to WA a year ago Oct, spent the winter sanding it, and had my car guy paint it. Corvette Yellow, Viper Red, $900 for the paint alone! Have proceeded to trash the paint job in one short season, shoulda found all the week spots and practiced docking FIRST, then painted it! Overall, despite a lot of early breakage, I'm absolutely enamored with it! It has a powerful, silky feel to it in light air, strong creation of apparent wind, and produces plently of adrenaline starting around 14 kts windspeed. It's the challenge I was looking for , I expect to be thoroughly entertained for years to come.
