I already have the sail rigging I need for the sailing row cruiser I intend to build. However, according to a post by Colin about a very similar (if not identical) boat I'll need to "move the daggerboard aft the forward end of the cockpit". I'm looking for advice on how to plan/design the specific details for this.
The rig I intend to use looks the same as that used Michael G of France (shown in the Sourcing Materials thread). It's from a couple of laser funboats. The sails are sleeved and 51.67 sq ft. They're reefed by rotating the mast (which I'm hoping I can reach from the rear of the cockpit and the open fore cabin hatch).
The image of Michael G's boat shows two identical sized sails in use and of equal size, which would be 32% more sail than using the Bic sails. It would be unbalanced if the dagger board is not moved.
Would I be using to much sail area?
How can I calculate/find the correct location of daggerboard for two identical sails?
Should I just stick with the planned daggerboard and keep the aft sail permanently reefed?
I think pivoting leeboards are the way to go. Not sure how I'll overcome the hull flare but I'll be able to have a range of positions and board rakes to blance things. As I'm 6'3" I think I'll probably move the forward bulkhead forward a bit and the mast ahead of the bulkhead to provide enough room to sleep in the cabin. This will also affect the balance compared to the plans so having adjustable foil positions will help even more.
Overall, I don't think it would be too much sail area. The standard configuration using the Bic Open sails is a relatively modest total sail area, so having 32% more should be manageable. My personal preference would be to simply trim one of the Laser sails down for a mizzen and keep it in the same ratio as the standard sail configuration. This way, you wouldn't need to make any design mods, and you don't need to worry about going wrong with the center of effort vs center of lateral resistance.
I think trimming the aft sail rather than having it permanently reefed would bee much cleaner. Trimming would involve either taking it to your local sailmaker or getting your hands on a robust sewing machine and doing it at home. The mast would also need to be trimmed - you'd need to look a the particulars of your Laser mast to see how this could best be done.
Thanks Colin, I'll give it some thought. I've got plenty of time before I need to make decision as I need to build a shed to do the work before I get started. The masts for these sails come in two pieces and the top part is just a straight tube, so shortening that would be no problem.
