You are mixing a lot of metaphors. Boats are a lot of trade offs. You can't get everything. What do you want? Is cost a consideration? Multihulls cost a lot because of the multiple hulls. Tall stiffly stayed masts cost a lot because of the complication, materials and stress on hull(s). Multihulls are skittery and jerky in motion in a seaway. Some people don't like this. Monohulls tip, sometimes a lot. Some people do not like this. Monohulls do not have to be deep drafted to carry a lot of sail, but if they are not they need a lot of sail area low down: gaff, junk, or lug sails. In a mono hull, length is the fastest means to speed. In a multihull, lightness, low drag, low wetted surface and tall windward efficient sails are the key to speed. High speed is a major reason for choosing a multihull. A moderate to heavy displacement mono hull with powerful sail plan will be least affected by dragging a prop through the water.
My boat is engineless because I do not have a good auxiliary solution. Sailing boat to boat against other boats was instructive. Towing a planing dinghy was a distinct handicap. It provided considerable drag. What happened when the 6hp short shaft motor mounted on that dinghy tipped back in the water was shocking. It was like dragging a sea anchor. Someone mentioned 20% reduction in speed. That seems like a good figure.
You have not even mentioned what you want to do with your dream boat other than charge batteries. Balance the list of desirable qualities of your dream boat and that will determine mono or multi hull, draft and sail form, and point the way toward how to recharge your batteries.
Eric
--- In electricboats@yahoogroups.com, Michael Mccomb <mccomb.michael@...> wrote:
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> Wanted to see what responses I would get to the following thoughts.
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> I've been going back and forth on which type boat is best converted to a regenerating sail plan and have now pretty much settled on a trimaran with a larger than average sail plan balanced out by whatever increased beam is necessary.
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> It seems to me that the only variable that comes into play concerning regen IF one can reach say 6 knots is the amount of power that the sail plan can generate. Displacement has mostly to do with acceleration and the only consideration to the reduction of regen capability with concern to displacement is that for a given same hull form a boat of increased displacement has an increased whetted surface area.
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> Even the 1.3 hull speed rule for figuring cruise doesn't seem too relevant when compared to sail plan size. A very fast hull will, during regen, be penalized at a higher percentage of that hull speed during when in regen mode. A trimaran which can be very fast due to very low resistance will give up a much higher percentage of it's speed if a prop is being used for regen than would a more normal mono-hull.
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> IF the above is more or less all correct then it would seem that the primary consideration when trying to develop good regen would be to make certain that one has the optimal sail plan in terms of power generation and that would necessarily point one at a taller sloop or perhaps cutter rig. Multiple masts carry more sail but with reduced efficiency so that the same boat with a commensurately larger single mast rig will be faster due to it's producing more power.
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> A taller rig then requires more keel to keep it where it belongs and the most efficient keel is the deeper blade type which adversely affects draft. And so even though the trimaran would give up a greater percentage of speed during regen it would seem that in order to get rid of the deeper draft required to offset a larger sail rig the trimaran would be the ideal regen platform as it may offset the larger sail plan with beam rather than, as must be done with a mono, draft.
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> am i missing something obvious???
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