To design a ballasted daggerboard? - SailNet Community
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post #1 of 13 Old 03-25-2011 Thread Starter
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To design a ballasted daggerboard?

I’d like to redesign a daggerboard, probably specified to the Optimist dinghy class to aid young and novice sailors to gain more experience more quickly and efficiently without the fear or worry of heeling and capsizing.

Many young and new sailors learn to sail in Optimists, due to their hull design and durable characteristics. I’ve instructed many people to learn how to sail and found at least 1 or 2 in each class will give up the sport due to an unexpected gybe which usually leads to the boat capsizing. I’d like to reduce this fear, to stop the children leaving the sport prematurely. I know that some people aren’t suited to the sport, and that’s fine, but if I recall learning to sail, I would have really liked the ‘training wheels’ or stabilisers so to speak to help me to sail more comfortably with more control.

I’d be really interested on anyone’s thoughts on the concept.

I would want the design to be able to fit in the current housing of the daggerboard slot. Anyone any thoughts on how the daggerboard could be designed with more stability? I’ve been looking at lead attachments onto the bottom of daggerboard? Or a rubber casing which takes on water as the dinghy gathers momentum creating a ballast. Again more ideas would be much appreciated.

I think there is a potential for marketing a product like this, but only for recreational users as the Optimist is a one-design and would not be acceptable in a competitive level. Maybe it could be used by Mirror sailors also. The daggerboard could be sold to clubs that teach the young how to sail rather than to the individual users as most money spent on sailing dinghies would be in the racing stages, however this is only my assumptions.

Thanks for your time and advice,

Aimee
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post #2 of 13 Old 03-25-2011
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This may be crazy, but could you put a bulb on the bottom? Granted, the hull won't be perfectly fair with the bulb up against it when the board is raised, but it might give you the extra stability you're after.

Perhaps an indention in the hull could be made to accept a bulb?

Otherwise, just making it out of a heavier material may be the way to go. But remember, they have to have the strength to raise it.

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post #3 of 13 Old 03-25-2011 Thread Starter
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I have considered that, but adding a bulb would add more problems, I don't feel people would modify their boats, especially for something that could be a potential short term accessory until the sailor gains enough experience to sail without the appendage. The weight of the board is definitly an issue, if it were possible to make the weight variable, depending on the sailors experience?
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post #4 of 13 Old 03-25-2011
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If you aren't already, you might start including a capsize drill at the very beginning of the class. Capsizing is pretty much an unavoidable part of dinghy sailing, so if the kids are so spooked by a capsize that they quit, perhaps disarming some of the trauma and stigma that goes with capsizing will help that.

As for the weighted daggerboard, when I owned a Daysailer, I heard of some pretty jerry-rigged contraptions to add some stability, so it's certainly on people's minds. Everything from casting the centerboard of lead to drilling a hole near the tip and lashing dumbell weights to it. There's a real limit to how much weight you're going to be able add to a relatively thin foil like that. I think a detachable bulb may be the best bet, as BH posited. Something like a beefy solid metal rod, ripped in half length-wise, with through-holes that match up with holes in the board. Simple as two bolts to attach it, and it comes nearly flush so it can still be beached; it just leans more to one side than previously.
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post #5 of 13 Old 03-25-2011
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Why not a removable/adjustable set of amas? If they are of sufficient angle, they wont create drag when running, and they will still allow some heel when reaching. Since they are adjustable, you can leave them at their widest setting, or retract them to reduce the amount of stability while still providing piece of mind to younger sailors. Come race day, simply remove a couple of clamps and you're class ready.
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post #6 of 13 Old 03-25-2011
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pontoons/outriggers ?

Sure you can add 20-30# to the daggerboard, but will that really STOP a wipeout ?

and of course the boat might sink since its now heavier.
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post #7 of 13 Old 03-25-2011
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It has been done and still is being done. I am seriously contemplating it myself, just a matter of making the time and taking the effort. I have a MacGregor 26M and they have daggerboards about 72" long but only 57" go below the hull bottom. They are hollow and fill with water to provide neutral bouyancy, but several owners have plugged the holes and filled the board with a 50# mixture of leadshot and epoxy and even added a steel rod down the length for added stiffness. The downside to this was having to beef up the pulley system to raise and lower the board because it is now much heavier. Those who have done it report good results but it does entail a bit of work and resources, which is why everyone does not do it.
The extra weight does not sink the boat anymore than adding an extra battery would or adding an extra person.
Adding weight to a dinghy daggerboard would not prevent a capsize completely but it would delay the point of capsize to some extent, enough to prevent 30% of them. It is not a crazy idea, but it will change the sailing characteristics to some degree, especially in a dinghy.
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post #8 of 13 Old 03-25-2011 Thread Starter
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Really appreciate all of the suggestions!

@jcalvinmarks; I don't intend to completly avoid a capsize at all, as its a huge part in sailing, and creating something that could do this would also put huge forces on points in the boat also. The main aim would be to keep the boat in control and stable as much as possible especially in heavy weather. I'll look into the detachable or a possible retractable bulb.

@PaulfromNWOnt, what do you mean by a 'set of amas?' It definitly sounds like something I should be looking into!

@ftldiver, had looked into pontoons! Thinking maneuverability may become an issue? Outriggers sounds like it could be viable, but, would you need on on each side, because it would only be effective on a certain tack?
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post #9 of 13 Old 03-25-2011 Thread Starter
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Thanks CaptKermie!!

Yeah, I've been reading a few blogs on the hollow daggerboards being modified. I assume these are all permanent fixtures within the boards? I would like the board ballast to be adjustable to some degree i.e. I could remove the stabiliser once I've gained enough confidence. I haven't found anything else on the web like it?
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post #10 of 13 Old 03-25-2011
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I really doubt you can add enough 'ballast' to make an appreciable difference in how an optimist would behave without adding enough weight to seriously compromise the boat, esp in the event of an accidental gibe/wipeout.

Also if flipped now these weighted boards could slide towards the hull making righting from the water more difficult.

I think both Paul of NWOnt and ftldiver are talking about the same thing... turning the opti into a trimaran.

My understanding was that Optis are already one of the most inherently stable training dinghies.

Ron

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".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
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