Hi, Mike, I agree, Jace has good points. Here's a thought....... Why don't you, instead of initially investing time/money etc in regen, get your trimaran setup, use minimal batteries, to save costs, and re-evaluate what you need? The key to success might be the low weight, rather than the regen. Especially seeing as you intend to carry a diesel as well. But it is an interesting subject, seeing as with a tri, you will/might get away from the powerhogging as hull speed is reached. Also, with a tri, you have lots of potential area for solar panels. You might find that regen is not worth the resources to set it up. Final thought - you might find that a multi-bladed prop, as in, maybe at least 5 or 6 blades, might give the best results, as it would/should generate more torque at lower revs. And cause more drag, of course, so it might be good to have it retractable. John 1e. Re: (to Jace) regen, displacement, sail plan, hull form.... Posted by: "Michael Mccomb" mccomb.michael@yahoo.com mccomb.michael Date: Wed Oct 10, 2012 3:51 pm ((PDT)) I completely agree with what you are saying here. I like to sail, not motor. To the extent that I can do completely without a motor I am much happier. The trimaran format allows one to go from point A to B more quickly and therefore more reliably. I quite like the idea of the Fisher boats and the 37 especially BUT the darned things are doomed to be motorsailers (lousy sailers) pretty much no matter what you do to them. For my purposes much better to have a trimaran that can move right along under normal circumstance AND one with a larger sail plan so that a significant amount of power can be consumed by the larger prop of a maximally efficient REGEN/propulsion system. A larger prop works better for regen because it has the ability to convert more of the power that is ultimately provided by the sail system. If one wishes to sail without penalty of regen one simply turns the prop over at a speed that neutralizes the large props drag. Adding even more power than the required neutralizing revs provides propulsion and adding less power than the neutralizing revs to the prop provides regeneration. I need propulsion on the boat but the efficiency of the prop in propulsion is not nearly as important as the efficiency it has during regeneration. So for instance I'd rather have a propulsion to regeneration efficiency ratio of 40/60 than 60/40. Propulsion is only for getting away from the mooring, handling tides when necessary and emergency situations such as storm or dead calm conditions. I want a serial hybrid with a highly efficient diesel dc generator used mainly to drive an electric motor when the batteries run too low on juice to do so. Trimarans should be as easily driven by electric motors as they are by wind and therefor I would expect a decent turn of speed on good sized trimarans for even motors considered to be smallish (such as the ME0913). All of the above says MAINLY that the propulsion system is a backup that I wish to use a little as possible because, i wish to sail not motor. kind of an aside to the above but one fellow suggested that a normal prop mounted backwards would produce the best regeneration.... intuitively this seems correct to me.... it would be less efficient in propulsion mode but probably maximally efficient for regen..... you seem a knowledgeable fellow and I wonder if you would you have any thoughts on this???
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