Re: [Electric Boats] Re: Electric speedboat revisited

 

agree absolutely, same concept and questions.. once on plane might be consistent 14-15 mph and the boat grows some reach-range. might be it wants 15-16 mph to stay in a decent slow plane, it'll be neat to see it reported. on calm water theres about gotta be a "magic number" for speed with low current draw. wouldnt expect it to be greater range than at trolling speeds, but it'd be cool to see its cruising speed-range. it might want to run 23-24 mph, more on step, less wetted.   I'm simple minded, but know if its drinking 100 amps at 12 mph and 160 amps at 20 mph you're gonna do 20, same as if its drinking 300 amps to do 30, much better range at 20. am sure it'll be a bit of a chore writing down all the speeds and watts/amps, but I'd sure want to know near exactly what to expect from it  :)   --- On Wed, 5/30/12, Eric <ewdysar@yahoo.com> wrote: From: Eric <ewdysar@yahoo.com> Subject: [Electric Boats] Re: Electric speedboat revisited To: electricboats@yahoogroups.com Date: Wednesday, May 30, 2012, 12:40 PM   Hi AK, Congratulations on getting the boat up and running. And it looks like she can really run! If you get a chance, I would be interested in hearing what your measured "watts to knots" performance is. While cruising around at 28kts looks fun, the range can't be good. What I'm really interested to learn is if there is an optimal speed with the boat planing that gives more range at a reasonable speed. It might have greater range there compared to much slower displacement speeds. We know that in displacement mode, the speed to range graph is exponential. I think that your speed to range graph will have a notch in it where your energy requirements "reset" down to a lower figure right after the boat get up on a plane. From there I would expect the typical exponential progression that we see in diesplacement boats. When I did my performance testing, I tried to make sure that I held specific throttle settings for at least 30 seconds to give the boat a chance to settle into its actual speed for that power output. If you go up in 5A increments, I would expect that you'll hit a wall (no appreciable speed increase for a number of throttle increments) before the boat pushes over the bow wave. At some given increment, the boat speed should jump as the hull comes up on plane. Then while your bringing the throttle back down through 5A increments, you should find that your speed will stay higher through the same settings that wouldn't get you up on plane. Finally, the boat will drop back into displacement mode and you'll be back with the rest of us "slowboaters". I'm excited because you have the opportunity to provide real world data to support what we all "know" about planing hulls. A digital ammeter gives much better visibility into the actual energy consumed. With an ICE, the best I've been able to do is fuel consumption, and that's not granular enough to put together a detailed graph. Again, congratulations on a job well done! Fair winds and smooth seas, Eric Marina del Rey, CA --- In electricboats@yahoogroups.com, "ams_ak@..." <ams_ak@...> wrote: > > > > Have not been active in the group, but would like to share a vid of our first outing wih the Electric Speedboat: > > http://youtu.be/yt-F7meWNzA > > Thanks Roderick, Eric and Dave for some encouraging words here, while we were still in the brainstorm stage of the project. > > regards > > AK > New Electric >

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