Originally Posted by Louann
You may be correct...an electric motor might be my best bet. Perhaps I am being too overzealous in my idea of a water jet? Thanks for your ideas. I'll keep all information in mind as I sift through the information. Lou
Check out this site for a realistic, honest look
at electric auxiliary propulsion
in sailboats. It isn't for everyone, but for those willing to be realistic, it is hands down amazing.
Your best bet is going to be with a big, high pitch
prop turning slowly. My Catalina 30
is fit with a 12.5 x 14 Acme prop. If you take Practical Sailor, on the page with the interview with James of Propulsion Marine
there's three photos, one of which is a prop. That's actually my boat and prop when it was in the yard. Electric motors have full torque starting at 0 rpm
, so you really lower slip rate and increase efficiency by selecting a big steep prop. A waterjet just doesn't scale down to our size and speed efficiently. It's possible to make cabinets with a chainsaw, just not very efficiently.
Range can be a problem. One of the more realistic electric boaters is always telling people that the most practical battery
pack is about the energy equivalence of a single
gallon of diesel. If you're happy burning less than a gallon at a time, you're golden. It's definitely not for people who employ auxiliary sails
on their slow powerboat...
The real beauty of an electric conversion is the idea of electric sailing. The motor is basically always running. It takes about 50W of power to spin the prop up to the current
boatspeed and eliminate drag. This adds about a knot
of speed for sailing. By kicking in about 250W, you can increase sailing speed by two knots. Imagine being able to motor sail with your diesel, except doing it at really low power
levels (which is bad for a diesel) and without the noise
, vibration, and stink.
As far as charging
seems to be the most popular, although the usual caveats of lattitude apply. The usual arguments for and against wind generators are pretty much valid with electric. Regeneration, or regen, is using the prop to turn the motor as a generator
. It doesn't really work as well as one would hope. Most folks with boats in my size class are getting somewhere around 80-100W max at 6 knots boatspeed. The hype is there, but the physics just don't work out so well without a bigger, faster boat.
-- I think electric auxiliaries are going to really take off in the next few years. They aren't the solution to every situation, but they're a *really* good solution to several.