Dagger board with added bulb
- Thread starter Cappn Mark
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never heard of that... hard to get on the trailer, no?
I do know some have added weight to the bottom of the dagger board, and some have even cut the ballast and added weight there.
IFAIK You'd be first!
I do know some have added weight to the bottom of the dagger board, and some have even cut the ballast and added weight there.
IFAIK You'd be first!
Yes,
The MacGregor dealer in Seattle, Blue Water Yachts, built an experimental 26M named "La Perla Noir", with a lead bulb at the bottom of its dagger board.
In addition, a 26M owner in the SF Bay area has added a considerable amount of lead to his boat's dagger board.
There are probably others.
I asked an engineer who is very familiar with this boat design about this idea and he suggested that a weighted dagger board actually detracted from the boat's performance.
A possible reason is that the water ballast already provides adequate "righting moment" and the additional weight increases the displacement/ hull resistance.
The MacGregor dealer in Seattle, Blue Water Yachts, built an experimental 26M named "La Perla Noir", with a lead bulb at the bottom of its dagger board.
In addition, a 26M owner in the SF Bay area has added a considerable amount of lead to his boat's dagger board.
There are probably others.
I asked an engineer who is very familiar with this boat design about this idea and he suggested that a weighted dagger board actually detracted from the boat's performance.
A possible reason is that the water ballast already provides adequate "righting moment" and the additional weight increases the displacement/ hull resistance.
I think the idea is........
I don't think it is a good idea to do this. From what I've been told the idea is to add weight to the end of the center board so that the added leverage will allow the boat to be sailed in light wind without any water ballast. With 400 lbs on a 5 ft board this would be a dramatic improvement in light air performance without the 1200 lbs of water. I think the weight on the end of the board will result in increased drag and so the gains if any will not be very great for light air performance.
When the wind pipes up the ballast tank would be filled and then the boat would not be as tender by combining both. I think the Mac is well designed and balanced with respect to sail area, mast, rigging. By trying to keep the boat upright when the wind picks up it could overload the mast and rigging.
Bob
I don't think it is a good idea to do this. From what I've been told the idea is to add weight to the end of the center board so that the added leverage will allow the boat to be sailed in light wind without any water ballast. With 400 lbs on a 5 ft board this would be a dramatic improvement in light air performance without the 1200 lbs of water. I think the weight on the end of the board will result in increased drag and so the gains if any will not be very great for light air performance.
When the wind pipes up the ballast tank would be filled and then the boat would not be as tender by combining both. I think the Mac is well designed and balanced with respect to sail area, mast, rigging. By trying to keep the boat upright when the wind picks up it could overload the mast and rigging.
Bob
Thanks, I found the article on the lead bulb at
http://www.bwyachts.com/
I have never tried sailing without water ballast. I think Aurcave II wouold be a little "tender", since even getting on while the balast is not full makes her list wildly.
I dont know if this works, but I copied the pic of the bulb to this message.
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http://www.bwyachts.com/
I have never tried sailing without water ballast. I think Aurcave II wouold be a little "tender", since even getting on while the balast is not full makes her list wildly.
I dont know if this works, but I copied the pic of the bulb to this message.
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I stand corrected. this is a newer model M w/ Daggerboard. don't see any pics of the bulb...
http://www.bwyachts.com/La Perla Noir/Pearl Home.htm
of course this was a one off 'dealer-factory' effort, designed in added strength to handle the extra loads. doubt you could do this to a production boat.
http://www.bwyachts.com/La Perla Noir/Pearl Home.htm
of course this was a one off 'dealer-factory' effort, designed in added strength to handle the extra loads. doubt you could do this to a production boat.
When I had my daggerboard made by Idasailor, I asked them to add extra weight to the new daggerboard. The new dboard is also a few inches longer (deeper?) than the original.
In the case of the Mac 26D model, the daggerboard is positioned directly over one of the trailer rails when the boat is placed on the trailer. This is probably an idiot proofing design advantage. The frame of the trailer is so close that there exists little room for a bulb attached to the dboard end. Since a bulb would not fit down the daggerboard well, having a bulb would require diving to install. John S
In the case of the Mac 26D model, the daggerboard is positioned directly over one of the trailer rails when the boat is placed on the trailer. This is probably an idiot proofing design advantage. The frame of the trailer is so close that there exists little room for a bulb attached to the dboard end. Since a bulb would not fit down the daggerboard well, having a bulb would require diving to install. John S
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