Okay - another question for the multi guys - daggerboards.
So, if I'm understanding this correctly, daggerboards are primarily for upwind sailing. And, from what I understand, they buy you another 10° or so of pointing - putting you in roughly the same range off the wind as a mono.
BUT - the arguments go that "well-designed" fixed-keels will get you within 5° of that, and that the added rigging, mechanics, etc. for daggerboards is not worth it in the long run unless most of your sailing will upwind and/or racing.
What do you guys think? If 10° - or especially 5° - is really all I'm losing, I'm not sure it's something I'd insist on.
You can't really look at it that way because in almost all cases, you will be comparing apples to oranges because you will be comparing completely different hull designs. For example, an Outremer 45 with daggers is going to far outpoint and go faster upwind than a Lagoon 450. Probably more than 10*, but also with a much better VMG.
What you need for your analysis is the same boat built with daggers and mini keels.
Erik LeRouge has done just that, and builds many of his boats both ways. I think I remember Derek Kelsall and possibly Kurt Hughes have also. I believe Chris White has done engineering analysis along this line (don't know if he actually built any both ways). In these cases - the same boat with different keel/daggers - they found that the performance differences were not that great, and mostly manifested in light air. But there were measurable performance differences across the board. LeRouge stated that daggers were definitely needed for higher performance, but that a cruising tradeoff of mini keels was a reasonable one for their benefits, while still retaining reasonable performance.
However, they build fast hulls. I don't think sticking daggers on a Lagoon 450 is going to help it much.
So the dagger/no dagger debate is really a proxy for what type of hull shape and boat philosophy one has/wants. Catanas and Outremers are not higher performance boats because they have dagger boards. They are higher performance because they have narrower longer hulls, lighter weights, and better proportioned weight distributions than Lagoons and Fountaine Pajots. Put mini keels on the Catanas and Outremers and they will still walk away from the Lagoons and Fountaine Pajots. Put daggers on the Lagoons and FP's and it won't help them much.
However, put 8,000lbs of stuff on them and the Lagoons and FP's might just walk away from them.
The dagger catamarans I've sailed go upwind very, very well. Better than almost all cruising monohulls, and the same as the more performance cruising monohulls. They also do better than similar build mini keel catamarans. The difference is real, but the tradeoffs are also.
Personally, I like sailing dagger catamarans, and when we are in light air, or hard on the wind needing to pinch, I wish we had daggers. For all other times, I am happier with mini keels. An approach like Chris White's of a foil stub for protections and sitting on, combined with daggers, is probably the best.