Thanks, Carter---it looks like he's been active on the ElectricSeas.org forum since last Summer, so I guess it's not totally a shot over the bow, so to speak. And reading his last blog post ( http://electricbluesolaryacht.com/wordpress1/2015/07/14/challenge-to-race/ ) they make it sound like the challenge to race came from you J --- so I guess you inspired him/them to do more than race to DC…
I've watched the 20 or so Youtube segments that Robert Brown posted on their trip across and up Florida to Clearwater and I've reviewed the specs on the yacht. It was enjoyable watching the videos. I kept waiting for a tour of the electric motors or batteries or anything electric in those videos, eventually realizing that they made that journey primarily from propulsion of an 80HP Suzuki gas outboard. Later I find from their Facebook page that there wasn't anything electric about the boat up until pretty much now…it looks like they now have a NetGain Warp 9 motor for propulsion (a series-wound motor with 40HP rating @ 72v) but plan on powering the boat (and controller) with a 48v, 48kwh pack. This limits its power rating to about 30HP. The specs also note a cruise speed of 8.64knots (80% hull speed) and a cruise power of 3.5kw---realistic? This gives a performance efficiency number of 2.5 n-mi/kwh, or 400wh/n-mi. The numbers seem realistic or aren't probably far off.
For an array, the claim is a 72.5m^2 solar array with 20% efficient panels --- i.e. a max. of approx. 14.5kw of power, or maybe 10kw nom on an average day? On a given day then, between 50 and 90kwh (big swag…) could be expected from the array in Florida. If they plan on 80n-mi per day, this means they better be able to travel at 0.625 – 1.25kwh/n-mi to do it. So assuming their 400wh/n-mi is real for 80% hull speed, conceivably they could bump this up a knot if the weather is favorable. Now, is 48kwh of lead-acid battery bank enough? At 400wh/n-mi and assuming 60%DOD max, we get about 29kwh/0.4kwh/nmi ~ 72n-mi. It seems that a 2.3-ton 48kwh pack is a bit oversized given the solar array, but assuming cloudy weather on occasion, likely not.
It should be interesting…thanks for informing us of this adventure/challenge!
Anyway, it still looks ambitious --- Perhaps 600+ hours of cruising to do that loop!
-Myles
From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com]
Sent: Wednesday, February 03, 2016 7:50 AM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] Solar Electric Regatta
I concure with your analysis. I actually met this guy a few months ago as he passed through La Belle and told him about this group in our conversation but I guess he never joined. We just spotted his website last week so I don't think it's been up that long. I was pretty sceptical about the time table too. I've completed several of those course legs that he listed for Florida myself on solar power only and even with perfect weather it's a very, very optimistic time line.
I agree there are probably numerous boats out there that could compete in a race like this but if someone was serious about putting it on they should be planning for doing it in 2017 season, not next month. Something like this would require months, if not years of planning. This guy hasn't even finished his boat yet and the race starts next months? More power to him for trying but I have my doubts he'll make it this year. He'd have to be to the locks in upstate NY by April to get across the Great Lakes over the summer. There have been several attempts at doing the loop on solar but so far no one has managed to pull it off. "All Solar" cruising is tricky business if you're relying strictly on the sun for ALL your power with no backups. It's not nearly as easy as it sounds.
I have hopes of completing the loop on solar some day myself but after crusing nearly 2000 miles around Florida as a test run I determined I'll need to do a little more work on the Arc before making an attempt. I'll be trying out some new upgrades we're making on the Arc when we head to the keys in a few weeks. Crossing the Bay of Florida from Marco Island to Marathon will be a good test to see if we're anywhere near ready for the Great Lakes. So if my upgraded systems works as well as I hope, maybe next year. We'll see if the record still stands by then.
Capt. Carter
www.shipofimagination.blogspot.com
On Tuesday, February 2, 2016 1:56 PM, "'Myles Twete' matwete@comcast.net [electricboats]" <electricboats@yahoogroups.com> wrote:
Interesting race…oddly, there's but one sponsor (a lead-acid battery manufacturer named "First Charge, 'Clean Energy Stored Here'"), zero information on one of the boats and nearly zero information on the other of the 2 boats entered in the race. And the only info on the 2 teams is a lengthy 'military electronics and weapons systems' career bio on the program manager/captain for one of the teams ("Lee Wheelbarger, inventor"), who happens also to be the "race director". The boat: a 40ft sailboat being converted to solar.
I suppose it's a nice way to get funding for a fun trip, but pretty self-serving in its being nearly a secret race. I say nearly secret because until now, this has been completely off the radar to this group---and certainly there are at least a couple folks on this list who are at least close to having a vessel that could do that trip if given enough advanced notice. That this "race" is just 40 days away, that the focus seems to be to set 2 Guinness World Records, that the organizer is also the main competitor and that the organizers didn't bother reaching out and informing groups such as ours of the race all suggest that this is largely a self-promotional event. Still, it would be cool if one or more of the folks on this list could get registered, boat optimized and blow the doors off these 2 "newby" solar electric boats…
Note: They should at least correct the spelling of their 3rd mandatory stop in the race---"Steward, Florida" should be "Stuart, Florida"
Technically, this is an ambitious "race"---each of the first legs of the trip look to be about 90 miles each. Let's say you could achieve a 7mph average solar cruising speed and let's say that cost to go that speed is nom. 600wh/mile (40ft sailboat est.). Then it would take approx. 54kwh to do each leg. At 7mph, the 90miles would take nom. 13hours---several hours longer than the solar day, so either the solar array needs to be much bigger to maintain that average speed or each leg of the trip needs to be a 2 day trip. Let's say that one wanted to do it in one solar day and let's say you used 20% efficient panels: In March in So. Florida, the insolation is nom. 5-6 kwh/sqm. Available energy from PV would then be of 1250-1500w-h/sqm. For 54kwh capacity, the array would need to be 36-4sqm in size---an array that's 3m wide by 12-14m long might do that. But then, your 40ft boat is 100% covered in commercial 20% solar panels to do that…doable, but pushing it.
Now, as we know, there's a steep range cost paid for speed. Slow your boat down by 1knot and the power drops by half, typically. So in the example above, an array half the size (27kwh/day) should allow the same boat to go 1kt slower (5.9mph) and still make the "day trip" taking about 2 hours longer to do it. But since this is a "race", why race to get there in 13 or 15hours only to wait until the next day to go? Wouldn't it perhaps be faster and more efficient to cruise slower and carry enough stored capacity to travel 'round the clock'? At 90 miles/24 hrs, a boat that travels just 3.75mph round-the-clock will average the same speed as the one that ran at an inefficient 7mph and petered out in 13hours with the same solar array, right? Not really: The boat traveling at 3.75mph would use between 4x and 5x less energy to do that trip than the one that cruised at 7mph.
But night traveling costs in terms of storage---maybe 2x-3x the daily KWH from sun needs to be stored and managed. So that capacity, weight & space needs to be balanced against just brute forcing a larger and more efficient solar array...
So, there are plenty of options and strategies to choose from if the race is truly a race over the long haul and not just a race between checkpoints. But in reading the race's website, it's not at all clear what the rules are. Here's about it:
"All teams must be fully self-sufficient and encouraged to deploy the most innovative approaches to energy management. Each leg provides interesting and unique challenges and spectacular scenery.
There are mandatory check points to ensure safety over challenging water bodies and where local events are scheduled. Mandatory stops offers captains and navigators the opportunity to update themselves with the latest information on the weather and their own position in the field. Here teams may perform maintenance and stock up on provisions.
There are also undisclosed check points which may be imposed by the event officials to ensure regulatory compliance."
Will teams be allowed to start off with 40kwh of energy to start with? The focus seems to be 'checkpoints' and no constraints on rules.
And the application form seems more about revealing who the organizers' competitors might be than anything:
And it's "bus voltage", not "buss voltage"…
There also doesn't seem to be anything about cost to enter the race, prizes or anything…so again, this all seems to be a self-serving stunt for 2 teams who decided to invent a new Guinness World Record and to ensure that they would win it by not actively inviting competition with enough time to join. Hey you Wye Island Challenge folks---why not establish a Guinness World Record for the race?
-Myles Twete, Portland, Or.
From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com]
Sent: Tuesday, February 02, 2016 8:03 AM
To: yahoogroups
Subject: [Electric Boats] Solar Electric Regatta
Found this on the web. Is anyone here thinking of competing in it? (or even heard of it)
Capt. Carter
www.shipofimagination.com
Posted by: "Myles Twete" <matwete@comcast.net>
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