After reading a bit about Kris Nocholas's Mini-Cup "Cheap Thrills," I saw that people had said that the sloop rig might be too much sail area for the hull. As I too have been thinking of building a Mini-Cup with a non-lateen rig, I went and read the specifications about many of the boats in this size range, and the variation seems to have some contradictions. The Wing-Dingy has a sail area listed of 110 sq ft (30 square feet more than Cheap Thrills according to my calculations), while it has a hull that is 8 inches narrower. The default mini-cup rig is only 75 sq-ft. If the mini cup has more width in nearly the same hull, why don't the stevenson's put a larger rig on the mini-cup? I understand there are other factors, like the height and weight of the rig (and a gigantic lever arm) but it seems so easy to fit 110 sq feet on the wing dingy, and only 75 on the miny cup. And then, why do people say that Kris's boat Cheap Thrills has too much sail area when I calculate it at about 80 square ft? (I know it's a taller rig, but it's not much bigger, and many times more pleasing to sail I'd think). Another apparent contradiction: the Mini-Cat while 2 feet longer, is 2'8" widder and much more stable than a wing dinghy, but the Stevenson's call for nearly the same sails (Mini-Cat appears taller, but I don't know how much taller). It would seem to me that there is plenty of room in some boats to comfortably expand the sail area.
Matthew Peter short sailed all of these boats in the name of safety. As was explained to me , not knowing the sailing expierience of the builders Peter felt that the prudent course was to specify a smaller sail set than the boats could carry to add a safety factor to the boats. Even my Vac has insufficient fore sail as specified. Many have cutter rigged their boats to great advantage adding ~ 50-80 ft more of sail. More sail can safely be added but don't go nuts with it. :lol: Happy Building....
Matthew, the wind dinghy behaves more like a trainer. While Kris's Mini Cup behaves very much like a Laser and will plane easily. The Mini Cat has less wetted surface and is very much like a Hobie, my Dad has one that he actually uses a Hobie Cat rig on it.
Sail area assignment can be a difficult aspect of any design, more so if the craft is intended for the home builder who may have less then stellar sail handling skills.
I have a large collection of old plans and books on design by all the greats. Some of these have sail area graphs to help the budding designer find a high and low range for a boat they're working with. I get a kick out of it when I check what was recommend in the 1920's for a small gaff sloop. 1927 by Skene would place it about 275 sq. ft. for Weekender and 450 sq. ft. for Vacationer. In 1936 by Chapelle the rig decreases a little but 235 and 400 respectively for each boat. We don't sail like they did then, nor is it likely we'll have as large a crew with a similar skill level.
Erring on the side of safety is generally a wise thing in most engineering endeavors, you can always add area. In usually boils down to researching the amount of light air performance the boat is intended to have. Weekender has good light air performance and her sail area to displacement ratio reflects this. Vacationer could use more area, percentage wise, then Weekender, but still has reasonable light air ability. Both boats could have area increases, but would also require earlier reefing, more hiking out to hold them down and running out of reefing options in lesser wind strengths. There's not much worse then a "witch" a term used generations ago to describe the sailing qualities of an over canvassed boat. I've sailed a few of these and they are race machines, twitchy, difficult to manage at times, sometimes imposable, ill mannered beasts, but they are fast, if wisely looked after underway. I'll take a kinder sail in a slightly under canvassed boat any day, lest I get caught not paying attention or run into a bad blow. Drifters, big lappers and spinnakers can liven up your day if you want one.
Has anyone tried a Laser Radial rig (mast, boom and sail) on a mini cup?
It has 62 sq ft of sail area and, theoretically, should work fine, provided the mini-cup mast slot is modified to support the mast adequately.
If anyone has tried it, could you please tell me whether it worked out?