COMPARING TWO HAKA DESIGNS WITH DAGGERBOARDS
First, I'm a performance sailor and a woodworker, what I'm doing makes sense for those purposes, though not necessarily for others. Two things: I wanted to start seeing how light I could make a haka; and, I want to give my AI2 more useful lateral surface area, because I don't think the CB supplied is enough.
I built one haka last year shown below. I don't need that little crossover extension anymore, so I've done away with that. The hakas can be moved outboard, but I have physical limits on getting over to them at my age. I do want enough room between the hakas and the main hull t paddle when the water's too shallow or weedy for the mirage.
The one I just built is 1/8 marine ply skins with ribs inside. The thing about doing this is that you don't want to underbuild the first try when you can't really estimate the strength. So it's overbuilt in terms of scantlines. Edge pieces are 1 1/4" by 9/8 (5/4 clear pine). Longitudinals are 5/8 wide and perpendiculars are 1/2 wide. Since it's hollow I had to put in special angled cross pieces to screw in the aka mounting parts.
Because it's overbuilt, I only shaved maybe 2.5 lbs. Surprised at that. The haka in the first picture weighs about 12.5 lbs. The new hollow one weighs just about 10.
Here below are pictures of the arrangements for daggerboard slot, securing the mirage drive, mounting a passenger seat, and securing the daggerboard when not in use. The slot has a shallower outer trunk and then a deep inner trunk that I can dismount for travel and storage. The outer trunk is just as deep as the aka mounting pieces so that the bench will sit level when the top is up.
Here's are shots of both hakas. I'm leaving tomorrow for two weeks in a cabin on the Eastern short of Lake Ontario, and will be comparing these two designs.
Since placing the daggerboard relative to the center of effort of the sail is guesswork, I've put the daggerboard slots in slightly different places on each one to get a comparison. I don't really know whether all the work that went into the hollow bench was worth it for 2.5 pounds gain in lightness. Also, the original bench is perhaps prettier. Next year I'll probably build another of the original type, or else go to an even lighter inner structure for the hollow one.
Whatever, building the hollow one was a worthy and fun project from which I've learned a lot constructionwise and will learn more in terms of usability. Here's a shot of both benches in the back of my stationwagon for travel
Next to the benches is my front dolly for the AI2. This takes the weight off my arm when I'm pulling the boat around on the dollies.