I take it you're using the old board as a core, and adding a "slurry of fiberglass" to the margins, then fairing the margins to shape a modern daggerboard? 'Confused as to the use of "a core", when you've really adding to the margins. Also confused as to the makeup of the "slurry". Why is it that color?
Trouble is, as soon as the mahogany gets a trace of water in it, the wood swells, and pops the fiberglass off the wood.
I prefer using the rounded board; therefore, I would have started with either of my Barrington or Shadow boards, and sanded the bleep out of it.
My MEK is red...and gives the finished fiberglass a mahogany color. The board was sanded well at the edges too so there is plenty of fairing and material to adhere to. Water will never find its way to the wood. Fairing and final coating with West Sys with white pigment in it. Ive added lots of extensions in the past and this wont come apart unless I slam into a rock at 6kts. The trunk might suffer more. Im also adding cloth over the "splice" as well. I might have done something more industrial but this hopefully will do. The board as was...chattered away...so either modify or buy the glass board. The old board as a core just saved me time and materials and gave me an easy size reference without measuring every other minute. Its done enough to try tomorrow...so we will see. Should be 15kts and sunny tomorrow.
I realize the Sunfish glass board has a different bottom profile as well. Im experimenting. Now its the 44 inches (added another 5) but may extend slightly more too if this helps out. Able to better round the leading edge now too and taper the aft.
If it doesnt chatter and point higher, I'll be thrilled.
Great success!!! In 15+kts and maybe gusts as strong 25...NO DAGGERBOARD CHATTER! Even if it didnt sail better, this effort totally worth it. At times I got knocked in strong gusts a could clearly see the board....and kinda playing around wanted to stress the board as much as possible. Without going over I was able to almost pop it out of the water....just to look at it and check on it. I want to think I could point 5 degrees higher and less sideways slip for sure. Im thrilled. A final West System coat will tighten things up just perfect and give a uniform color
Its 44" at its' longest point. How much is "too" long and why would it become more "tippy"?
Obviously I dont care about class legal. Id make it 6" longer if ut would point higher and slip less. Draft isnt an issue usually
Too long is when the boat becomes over-sensitive to tack and wind changes.
The dagger board is part of the stability in how the boat heals over in
response to gusts and how much of the wind gust is translated into forward
motion. It's all a compromise and 'too long' will vary with the wind conditions. The
good part is you can adjust the dagger board by pulling it up, at least until
clearing the boom becomes a issue. At some point the Lanteen Sail is going
to be the limiting factor no matter how long the daggerboard is. Right now
you're the house expert in longer dagger boards so I'm eagerly looking forward
to your future experiments.