Hello everyone! I have been lurking and I thought I would join in with a 'what I would do' post. So of course, YMMV!
If I were going to put Daggerboards in a wharram
, I would put them outboard
completely, as lifting LeeBoards, and shape them to the hull's curvature, in a solid track glassed into the outer hull
, and heavily reinforced (think biaxial or kevlar.. non stretch anyway). If I had the dollars, maybe I would make the case in Aluminum! I would leave enough play at the top so that I could wedge it out with a few softwood (or maybe HDPE.. something soft and squishy that wouldn't expand too much, but would lock in readily) wedges to lock it in place. I might lanyard a rubber mallet to each side near the board as well to be handy.
I would shape the board so that the bottom section flared out a bit fore and aft, like an oar, so it couldn't come back up the track after being raised. At the top of the flare, I would put something to cushion the slam in a "I am really yanking the line very hard" situation when spooked in shallows (grounding/breaking) or in heavy weather
(worry over tripping).
I'd attach a strong lead from the boards to something up high that made sense with decent purchase
so I could yank them up very quickly from the cockpit
. Perhaps I would install a block on a stanchion base with a small overhang next to the board.
I would attach lanyards to the wedges to keep them in the boat after such a maneuver.
And I would absolutely carve a naked lady (pr perhaps.. mermaid..) figure into the top of the board :-)
All of this, and you don't need to redesign the boat. It's an entirely external change, less weight than a case or two of beer
(or about as much) and pretty simple and cheap
. I guess that means you would have to carry more high proof rum
to keep everything even...
If you hated the vertical board idea, then you could still go external with a board on a hinge that rotated down instead, but that's more complex. It does have its advantages though, as you would be less likely to break it in a grounding if you installed "kick up" capability. But since the sides are not slab sides, that would be tricky, unlike the below leeboard sharpie.
Not only that, but the hinge could have a lot of shear stress on it. With a solid track you could really go to town with reinforcement for small money
In all cases, make sure the board is weaker than the board trunk!
Anyhoo, I'm guessing the trick is figuring out *where* to put it. But I would imagine you can find the CB/CG if you are building it from scratch :-)
Also, as I recall
, stretching a Wharram Tiki 10% is pretty ok.. the designer
says he doesn't like it, but he also says it can be done safely as long as it isn't extreme, and the boat should sail just as well. even if you don't increase the B/LWL ratio. I mean thats essentially what he did with Ariki and et al, I believe.