| I have no idea who told you that a folding prop was so it would clear the weeds. The real reason is so it's more streamlined while under sail then a fixed bladed prop. But I also think it's to cause sailboat owners to spend more money then needed so in their mind they are going faster... On a fast clean boat yes they do make a difference but on a 5 to 6 knot boat you may see it over a long trip on short trips not really. Seeing how you are trying to do regen while under sail you have already decided speed is not everything you want and will put up with the added drag of trying to recharge your batteries... You can't have it both ways unless you are willing to spend big money. You are not going to get something for nothing when it comes to a sailboat. If you are really trying to do regen I don't understand why you are even messing with a folding or feathering prop. They really defeat what you are trying to do in the first place. Myself I would go looking around the used boat part stores and find a fixed pitch prop with 8 to 12 inches of pitch max. Like I said in another post pitch your prop or size your prop so your motor is running at or near peak RPM at the cruise speed you want while under E-power. Part of what I know about pitching a prop for charging comes from a friend that builds hydro-electric plants for a living and we started talking about low flow, low head down draft systems using 10 to 12 inch impellers, but he had made a few that used a 6 inch impeller the systems he was making were for water flows of about 400 to 600 feet per min. Oh his systems were putting out about 2 KWs He did a bigger one that was putting out around 6 KWs and that one used a 24 inch prop as I remember Yes I do understand you are going to have power losses do to water slippage around the blade tips, because they are not running in a tunnel like the down draft system is. --- On Mon, 10/3/11, Mike <biankablog@verizon.net> wrote: |
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