Silly idea? Swapping a daggerboard in a Mirror dingy for a longer balasted board

Discussion in 'Boat Design' started by a.g.turner, Sep 20, 2010.

  1. a.g.turner
    Joined: Aug 2010
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    a.g.turner Junior Member

    Still very new to boats.
    As some of you know, I've recently bought a Pandora International 22 which I'm going to be sailing in the spring.
    In the meantime, I've just bought a little mirror dinghy to get some practise in on local lakes and possibly the local harbour.

    Just a thought.
    Is it possible to replace the daggerboard with a longer, balasted board which would reduce the risk of capsizing?

    Of course, the board would have to go in through the bottom and so wouldn't be fully retractable, but still able to lift most of the way up, as far as the weight on the end.

    Is this an idea worth doing or is capsizing part of the fun of sailing an dinghy and part of the learning curve of sailing in general?

    I just want to be able to go out sometimes for a nice relaxing potter about and not have to worry too much about going over.

    Silly idea????

    Andy
     
  2. alan white
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    alan white Senior Member

    You can modify the board if you know how to engineer it properly. It will certainly add some righting moment but bear in mind any small sailboat gets the majority of its stability from shifting human ballast. The keel ballast contribution is limited by the weight penalty which slows the boat through the water due to increased wetted surface.
    In other words, on boats under a certain size, a keel ballast can be detrimental to speed even if it increases stability so why go to such lengths for added stability unless the goal is to make the boat self-rescuing.
    Much would have to be done to make the change. The slot would have to be reinforced, the board would have to be remade completely, and there would have to be a means to raise the new heavier board. Beaching would be difficult and trailering would be problematic.
    Also realize that an upright boat doesn't benefit from a fixed central ballast---- only when the boat is heeled does the ballast begin to have an effect, and such boats are not meant to sail at appreciable angles of heel. Yet a human being sitting on the rail has a huge effect in keeping the boat upright. So the significant benefit of keel ballast on a light dinghy would be in preventing turtling and assisting returning the boat to an upright position.
    Definitely not worth the effort I would say.
     
  3. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    If you put much weight in a bulb on the end of the dagger, first you'll need some sort of contrivance to lift it, most would use a mast mounded tackle. More importantly would be the affect this would have on the fittings in the rig. The most likely thing to break first would be spreader sockets or upper tangs. In short, sure you can place a hunk of weight under the boat at the end of the board, but you will also have to adjust for the increased rigging loads.

    The mirror is fairly stable pram, but capsizes are a reward if you screw up badly enough. This isn't an unwanted thing on a hot summer's day, but not so much in the waters around Wolverhampton (I'm assuming you've mis-spelled it, don't feel bad, I pray to Dog ever night, that my dyslexia will go away too). Take her out on relatively calm days, with winds below 15 knots and preferably below 12. If you are a gross novice sailor, then no more then 10 knots until you get some experience. On the other hand, your Pandora has ballast and isn't likely to toss you in the drink if you screw up. Don't get me wrong, you can capsize it too, but you've got to really screw up, almost wanting to capsize her and she'll have been yelling warnings at you for some time previous to the event as well. Learning to sail in a dinghy is the best route, in spite of the possibility of a capsize. In fact, this possibility should be enough to keep you cautious for while, at least until you have the respect necessary, which, unfortunately is usually because it scared the hell of you. This is a good thing and all sailors have this respect both for mother nature, who can piss on you at will and for boat handling skill, which at times is woefully inadequate for the conditions.
     
  4. Landlubber
    Joined: Jun 2007
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    Landlubber Senior Member

    ...learning the skills to keep a Mirror upright are the same skills used to keep any sailing vessel pointing sky high, so spend the time, not long, to understand the feel of the boat, you will most likely never capsise a dinghy again once you have mastered the basic skill...and your general yacht skills will be so much better for the basic understanding that you will receive.

    Learning to balance a boat, both sail wise and upright are essential basic skills that many have never achieved, you often see saild set wrong, helms hard over and other horrible things some people get up to...learn the basics mate , just like any trade, and you will be the better for it.
     
  5. anthony goodson
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    anthony goodson Senior Member

    The area of the floor around the centreboard case in a wooden Mirror is prone to rot,because water puddles in the rocker. This is what normally "kills" them, any additional stress here is not a good idea.
     
  6. a.g.turner
    Joined: Aug 2010
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    a.g.turner Junior Member

    Will leave her alone then :)

    Ok, that's all fine, I'll leave my little mirror alone then.

    I'm in insatiable fiddler and i'm constasntly looking at things that have been developed over many years, by people with much greater intelligence any knowledge than myself, and thinking "surely it would be better if it were like this.........."

    But I guess the mirror and other similar boats are the way they are because that is the best way for them to be

    I bought her as lots of people have been saying that dinghy sailing is the best way to learn properly so I want to get as much practise in in the mirror over the winter as possible before going out on the pandora in the spring.

    Andy
     
  7. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Everything happens fairly quickly in a dinghy, which is why it's a good instructor. When you get to a bigger boat, things slow down and your natural reaction, fine tuned in a dinghy for fear of taking and unexpected swim, will reward you with timely execution of a perfect maneuver or skill set in a stately fashion (as it should be). The best part is you'll look good doing it.
     
  8. Vulkyn
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    Vulkyn Senior Member

    Thats very good advice .... and very true ... when i was learning to drive, i got the worst car with the worst gearbox in existence. When push came to shove and i took my driving license the car in the test felt like a BMW (the car i took my test in was an old Peugeot 409 made in 1979!!!).
    I think ill learn sailing the same way :)
     
  9. latestarter
    Joined: Jul 2010
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    latestarter Senior Member

    You have made a good choice for a first boat, as the Mirror is quite stable and if you pick days where the wind speed is modest until you build up your confidence a capsize is not inevitable.
     
  10. keith66
    Joined: Sep 2007
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    keith66 Senior Member

    Most wooden Mirrors die because the bottoms go punky & you put your foot through the bottom,
    I have lost count of the number i have repaired & they all end up on the yacht club bonfire in the end, good little boats though.
     
  11. a.g.turner
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    a.g.turner Junior Member

    Heeeeelp

    Right, I drove 8 hours round trip to pick up my "bargain" mirror last nigh for £60

    And.........

    The hull is fine, all good and solid, no soft patches and although it needs a rubdown and re-paint at some point soon i'm confident it's ok.

    There'sa good mast and gaff and boom assemly and a spare mast and gaff.
    There's two sets of sails....

    But I've just been outside to rig it all up (it was pitch black when I picked it up) and although I got 90% of it together ok I'm not sure how the rigging and sail controls should be set up.

    The rigging cables all look ok, one going to the prow and one either side.

    The foresail slides up the front cable fine with a rope and pully to pull it up..
    It has a rope one the front corner which I assume shold secure to the prow where the steel cable attaches.
    There's also an eyelet for another rope, which I think, goes through one of the side clutches to let the foresail out etc.

    The mainsail is ok as well and looks to be in good order, it slides nicely up the mast when I raise the gaff although it doesn't look like the gaff goes as high as it should, might be just me.......

    However, with the gaff up as far as it'll go and the sail pulled right up the boom is still hanging down very close to the transom at the back

    There's a pully on the end of the boom - but I have no idea what to do with it

    There's another pully on the transom and again I don't know what it's for - are these two for the sail control or the kicking strap?

    There's basically no obvious kicking strap and no mainsail controll setup...

    Sorry for being such a beginner and bugging you for advice but I guess this is how you learn huh

    Does anyone have a nice clear diagram of how it all goes together?

    Thanks

    Andy
     
  12. latestarter
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    latestarter Senior Member


  13. a.g.turner
    Joined: Aug 2010
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    a.g.turner Junior Member

    Perfect! Thanks

    that's a great help - thank you :)
     
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