HarryProa Style Hulls

Discussion in 'Multihulls' started by ThomD, Aug 4, 2010.

  1. ThomD
    Joined: Mar 2009
    Posts: 552
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    Location: TO

    ThomD Senior Member

    What don't you get?
    "Raise, lower and reef the sail on any point of sail in any strength of breeze?"

    How is that part differnet?

    "Ability to completely depower and/or stop the boat on any point of sail?"

    Is this the ballestron or the una? I can do this by just letting out the sheets currently or rounding up (no longer on point of sail) or rolling in the jib, and pulling the cart over on the main and letting it out. Fully battened (wood and glass :)) so they don't flog badly.

    "No rigging to check each time you go sailing?"

    This is an issue, my spar fell down last week, though no harm done, not a good feeling if it had happened mid stream somewhere, rather than in front of the house. I feel dynex, next time, might be more secure. I like knots and splices, stuff I can see.

    "Nothing to replace every x years? Automatic first reef due to the bendy mast?"

    This might be really good, but it sounds like a lack of sail control


    "No rigging for the sail to chafe against?"

    That doesn't happen with my current rig. I think it has to do with people putting too large a mountain of sail up, in order ot have a boat that "goes to 11" . But I hear you.

    "No deck gear?"

    On smaller boats, one can really do without deck gear in a number of ways, but more ways is better for sure.

    "Localised loads which are both lower and easer to resist than a stayed rig?"

    This is what I don't buy, at least at the small cruising end. I am not saying I know the answer. I'm not a rig guy. I think the staying width compresion thing is pretty well understood, keeps the spar out of the accoms, and has many loads, but they are lower. I don't worry about mast bury, but I do worry about the mast. There is no free lunch, the carbon spar doesn't have rigging in this case, and essentially the rigging angles have been reduced to the envelope of the spar at far higher loadings in the spar. Carbon can take these loads, but carbon is also pretty easily damaged because it is loaded so near the surface. One nick and that is it. But over time, quite possibly already, the build for such spars will be well enough worked out, and the spar will be reasonably bullet proof, like carbon arrows. But it does depend on how rugged a spar is. If the intention is all low weight, and cost, then the wall diameter and armouring suffer and the spar may break. Mast raising and trailering worry me.

    "Build the mast and most of the fittings yourself and save money?"

    Home run!! Though it isn't cheap. I was looking at some material the other day, and I figure there would be 2K to soller for the longi fiber alone. Not too bad actually, but I think the gougeons paid 350 for the G32 spars and then rigged them themselves. I bought second hand spar from x racer.

    I agree that carbon is great, once you man up and move out of the cheap seats. Thing is wood is nearly free for me.

    I also think a WoodyProa™ is both a nicer name, and an interesting challenge, with a backup carbon spar building plan for later. Also, if you can't get a Full-Woody, there is always a Half-Woody - a spar with say four intra layers of carbon rather than 10.

    Bob Oram said this about carbon:

    "I’m very keen to try a free standing rig with this boat with a boomless main if possible. Its easy to run light weather extras on free standing rigs."

    sounds good, though I don't know what he is refering to...
     
  2. ThomD
    Joined: Mar 2009
    Posts: 552
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    Location: TO

    ThomD Senior Member

    On a similar tack. What about the new rudder advances proa testers are making. Why not on trimarans or cats. I see potential particularly in the smaller end of the spectrum where the board intrusion into the main hull is really a big space killer, and there are lots of other compromises.
     

  3. rob denney
    Joined: Feb 2005
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    Location: Australia

    rob denney Senior Member

    Stays, particularly the currently popular angled aft ones, make raising and lowering the main on anything broader than a tight reach impossible. You have to luff head to wind. On an unstayed rig, you turn the rig head to wind. Huge difference in a storm or a crowded marina.

    Ballestron and una. Rounding up is not always feasible while running with full sail and big waves in a squall. Stopping a stayed rig boat, other than head to wind is impossible. Huge difference for picking up people overboard or moorings.

    Don't forget chafe, sharp edges, cost, uv and extra windage. And don't let your bad experiences change the fundamentals. Keep going with an expensive variation of what failed last time.

    Get the mast right and it is quite the opposite. You get a puff and the rig automatically depowers.


    Keeps the spar out, but not the support under it, nor the bulkheads for the chainplates. Look at a Laser rig if you want to see something in the smaller sizes.

    Depends what you are measuring. The compression of a stayed mast is huge, and difficult to resist in a cat. Add in the forebeam trying to rip the bows off and the traveller trying to raise the stern and there is a lot of extra required. On a proa the stayed rig has tow top and bottom, a bulkhead to keep the hulll sides apart and an extra layer of db to resist the twisting loads between the beams. On a cat, there is even less.

    Lot easier to nick and damage dynex than it is carbon. More likely to be terminal, too. In my experience, your worries about damaging a carbon mast are overdone. El's mast has the boom attached to it, which makes it difficult to carry round. Consequently, it is often dropped or banged into things. It bounces round on the trailer when the ties come loose and generally gets a pretty hard life. Still going strong. I have just added an extra 2m to it to play with a bigger sail. Much easier than rerigging and extending a stayed mast, as is cutting it down if it doesn't work.

    If I can build one in my garage, anyone can. May not be to autoclave standard, but if you can work a vac pump, a squeegee and a string line it will be more than adequate.
    Raising a stayed mast is fraught. Raising an unstayed one with sheer legs or a gin pole is dead simple, and very safe. Carbon is remarkably tough stuff.

    The G32 was 20 odd years ago. I bet you'd pay more for the wire, turnbuckles, spreaders, block and tackles, ropes, cleats etc than 2 grand. 2 grand would get you 40 kgs of tow in Aus, more in the USA. Enough (plus 50 litres/13 gals of resin and some glass) for a 60'mast suitable for a 40' cruising cat or a Visionarry. Probably won't have to worry too much about trailering it. Or comparing it with the G32.


    All his boats. He is a big fan of unstayed masts.
    rob
     
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