Hi Pitt,
No worries. If you don't have good consistent data, then posting your results can cause more confusion than just a subjective "I love it!".
Unfortunately, subjective opinions may not be as useful to someone new that is considering a conversion. What I consider to be a huge success may be a bitter disappointment to someone else. Someone posted about a magazine article a few months ago where the owners of a converted cruising boat that was converting back to diesel after a few years of going electric. If I understand correctly, they used the same purchased drive system as many satisfied electric boaters on this group, and yet they were obviously unimpressed enough to justify going through another conversion and to write an article for a mainstream publication. I think that the conversation focused around the fact that the regen capabilities of their boat did not meet their expectations. But I believe that what they got was all they should have expected, it may have been their vendor that mistakenly set their expectations too high. As you've seen, my position is that regen is usually "oversold", and the real numbers don't live up to the vague "you'll be generating electricity everywhere you sail" that you see in some promotional materials.
I do want to thank the people that have taken the time to measure their performance and post their results. When I was first considering my electric conversion, back in 2009, there wasn't much objective data available concerning electric conversions. The best estimates for a 30' sailboat that I could come up with were 1500W for 3 kts and 4000W for 5 kts. Since then, my conversion has delivered 500W for 3kts, 1100W for 4kts and 2500W for 5kts. Almost all of the data published in this group by other 29'-30' conversions have been within 10-15% of those numbers. So now we know what to expect from my size boat and the more data that we can collect from different size conversions, the better that we can set the expectations of people that are thinking about taking the plunge.
Since I've become a local proponent for electric drive, I've had a number of people with bigger boats (40'-50'+) discuss converting to electric too. Since I don't have access to much real world data for large electric boats, it's difficult to quantify what kind of tradeoffs that they should expect. Most of these boats displace between 30,000 and 40,000 lbs so they have power requirements that are much greater than my little 5 ton ketch. I can fall back to my EV roots and spec out a much more powerful system than what is typically available from our regular electric boating vendors, but without realistic performance targets, I can't recommend that someone to commit their money and their boat to this size experiment. But the bottom line is that any boat can be converted to electric, it's just a matter of putting together a drive system that is well matched to the boat's demand. Quantified demand is the missing link right now.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, Pitt Bolinate <boombolinate@...> wrote:
>
> Hi Eric ,
> Don't take offense, I did do trials write up numbers one day with just the motor and no sails. There was somewhere near 1.7 kts of current that day and that's water current. The numbers are all over the place and there fore not accurate or relevant. Perhaps when I am next on flat still water I will do the numbers but till then you will have to accept my WoW factor as being a valid expression. I diddn't want to sound like I have the biggest or best, just observing that it's bigger than average on this site, but not bigger than many boats on my finger at the marina. Perhaps it's about the size that the average person might think twice about converting?
>
> Pitt
>
> Sent from my iPad
>
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