I have a Mac 26M-09 and wonder. Did you do this modification with 180 lbs lead. I am thinking of adding a bulb 400 lbs under the CB. Perhaps I have to build a new stronger CB. I will test the old CB next week.delevi wrote:In an ongoing pursuit to add ballast, prompted by my second damaged dagger board, I have done more research on the weighted keel issue. The first step was to explore adding some foam insulation on the interior of the trunk, since by DB has 2 inch chunks of fiberglass wedged out of it by banging around in the trunk, which seems to be much too large of a chamber for the DB. I would then get the board filled with about 150lbs of lead shot. After talking to my dealer, I was a bit discouraged. He wouldn't agree to making the mod for me for liability reasons. He did say, however, that there is virtually no risk in anything up to 200lbs of keel as far as the trunk strength goes. The risk is the board, thin as the glass is, not holding up to the added weight. I talked to three other shops, only one of which would do the mod... $1400. No thanks.
Then I called Joel at IDA sailor. He said that he could make a DB/Keel (new build, not modifying the existing board.) He could get about 150 lbs of solid lead in the lower 1 ft. and make the rest out of various compounds with an oak core. The end result would be a board that will be very strong, and weigh about 180 lbs, with 150 lbs at the bottom. He also would build it slightly thicker diameter than the stock board to fill more of the trunk so it doesn't bank around in there. Cost... 1/2 of what I was quoted to modify the existing board, and no trunk reinforcement or insulation would be required. He also assured me that the trunk will safely take added weight stress up to 200 lbs.
I'm pretty excited about this prospect and getting ready to order the keel. I'm guestimating that an added 150 lbs 5' in the water will effectively add about 400 lbs of ballast. If this is true, that's a 25% improvement, and should make a huge increase in reducing heel, adding stability and an overall improvement in sailing performance. Would love to get some feedback from you guys.
Fair Winds & Merry Christmas!
Do you know the righting moment (RM30) on the boat with and without the water ballast?
, and the other guy on this thread passed away a few years ago.