Watch this excellent presentation by a seasoned world cruiser:
So, you're thinking of going Electric...
- Thread starter ggrizzard
- Start date
A nicely put together video. He has clearly spent a lot of time and money on his research and trials.
I was surprised by the prices of his generators, but I have no recent experience with that.
I would point out that he needn't have talked about sailing against the counter current issue. Such a strain on the milage would be the same for any in-water propulsion system.
Clearly, there is a lot of cloud cover in the tropics. Considering his current investment, I hope he considered adding an at-anchor wind turbine.
-Will
I was surprised by the prices of his generators, but I have no recent experience with that.
I would point out that he needn't have talked about sailing against the counter current issue. Such a strain on the milage would be the same for any in-water propulsion system.
Clearly, there is a lot of cloud cover in the tropics. Considering his current investment, I hope he considered adding an at-anchor wind turbine.
-Will
Thomas's conclusion may be accurate, however, the data is provides is total BS. He clearly does not know the difference between and kilowatt and a kilowatt hour. And tell me where you can repower a 50 ft boat for $10K? A repower will for his boat will run in the $50+K range.
Here are a few examples.
Panels are not sold or marketed by the KWH, they are marketed and rated by watts. Generally good quality panels will yield about 3-4 times they nominal rating over the course of a day on average. Thus, a 100 w panel will yield about 300-400 watt hours. This has been my experience with the panels on my boat, it is what Nigel Calder estimates, and it is what Delos reported in a recent video. He likely has nine 700-800 watt panels, that would put his power production at 3 * 800w = 2.4kwh. Close enough to his 2.5Kw. With 9 panels he would generate about 22 KWH.
Ok, so if we do the math, he needs 730 kWh to go 528 nm. Let's do the math, that is 730/528 = 1.38 kWh/nm. What we don't know is at what speed he is traveling. What we should know is power consumption is not a linear function for diesel or electric.
He claims he can only go 66 nm on a full 22 kwh charge. I really have no idea how he is coming up with that number. I went to the Oceanvolt Website and looked at their calculator and estimated the WL and displacement of his boat, my numbers came up with a hull speed of 9.2 kt and a cruising speed of 6.4, close enough to Thomas's. At 6.4 kt the engine consumes 8.78 kw, which would burn through 22 kWh in about 2.5 hours while traveling 16 miles. Slowing down to 4.6 kt power consumption drops to 3.4 kw, about 6.5 hours of travel time for a range of almost 30 nm.
None of this should be very surprising, we all know or should know the relationship between power/fuel consumption is not linear, it is curvilinear, power/fuel consumption increases faster than speed. If you go into considering electric propulsion without knowing this relationship, then you haven't been paying attention.
What is also not surprising is his trouble with the Fischer-Panda generator. They don't have a very good reputation, if you have been following Sail Life on YouTube, you know their FP generator has not been working.
I'm not sure what Thomas's point was in making this video. He is obviously upset about having invested a lot of money into electric propulsion and is very disappointed with its performance. However, it is performing exactly as it was designed to do. If he had really done his homework and really understood what he was getting into, he would not be this upset (except perhaps at FP).
There is no one perfect solutions for all people. There are some who have traveled the world on sailboats without an engine or much in the way of electronics and all the gizmos many of us now consider essential. The problem here is not the electric power, it is a mismatch between the boat owner and the boat, it's a problem with a choice the owner made and now regrets. His chaotic rant with incomplete and inaccurate statements does little to persuade me to shun electric propulsion. It does persuade me to believe he didn't do his homework and he's looking for someone to blame. What he wants is for people to get behind him and his crusade against electric propulsion, it is unfortunate his argument fails logic.
Here are a few examples.
Panels are not sold or marketed by the KWH, they are marketed and rated by watts. Generally good quality panels will yield about 3-4 times they nominal rating over the course of a day on average. Thus, a 100 w panel will yield about 300-400 watt hours. This has been my experience with the panels on my boat, it is what Nigel Calder estimates, and it is what Delos reported in a recent video. He likely has nine 700-800 watt panels, that would put his power production at 3 * 800w = 2.4kwh. Close enough to his 2.5Kw. With 9 panels he would generate about 22 KWH.
Ok, so if we do the math, he needs 730 kWh to go 528 nm. Let's do the math, that is 730/528 = 1.38 kWh/nm. What we don't know is at what speed he is traveling. What we should know is power consumption is not a linear function for diesel or electric.
He claims he can only go 66 nm on a full 22 kwh charge. I really have no idea how he is coming up with that number. I went to the Oceanvolt Website and looked at their calculator and estimated the WL and displacement of his boat, my numbers came up with a hull speed of 9.2 kt and a cruising speed of 6.4, close enough to Thomas's. At 6.4 kt the engine consumes 8.78 kw, which would burn through 22 kWh in about 2.5 hours while traveling 16 miles. Slowing down to 4.6 kt power consumption drops to 3.4 kw, about 6.5 hours of travel time for a range of almost 30 nm.
None of this should be very surprising, we all know or should know the relationship between power/fuel consumption is not linear, it is curvilinear, power/fuel consumption increases faster than speed. If you go into considering electric propulsion without knowing this relationship, then you haven't been paying attention.
What is also not surprising is his trouble with the Fischer-Panda generator. They don't have a very good reputation, if you have been following Sail Life on YouTube, you know their FP generator has not been working.
I'm not sure what Thomas's point was in making this video. He is obviously upset about having invested a lot of money into electric propulsion and is very disappointed with its performance. However, it is performing exactly as it was designed to do. If he had really done his homework and really understood what he was getting into, he would not be this upset (except perhaps at FP).
There is no one perfect solutions for all people. There are some who have traveled the world on sailboats without an engine or much in the way of electronics and all the gizmos many of us now consider essential. The problem here is not the electric power, it is a mismatch between the boat owner and the boat, it's a problem with a choice the owner made and now regrets. His chaotic rant with incomplete and inaccurate statements does little to persuade me to shun electric propulsion. It does persuade me to believe he didn't do his homework and he's looking for someone to blame. What he wants is for people to get behind him and his crusade against electric propulsion, it is unfortunate his argument fails logic.
Not so. The direction and speed of the current won't cause the electric power to be used up any faster, relative to diesel. Speed through the water will remain the same in either case and the same relative progress will be made for the same relative consumption of energy.
That's not to say there isn't more range in a diesel design than in electric, just that, if electric can only get a tenth of the range going with the current, it will still only get a tenth of the range against the current. In both cases, drive originates from the vessel's ability to push against the water at x amount of force. That force requires a set amount of energy from the system. Whether or not the current is moving with or against the headway of the boat won't use more or less energy per hour. 6 knots is 6 knots through the water, not across the bottom. That is a different problem that has nothing to do with where the power comes from.
The video's case for the inefficiency of electric on a cruising boat is made well enough without mention of driving against a current. That shouldn't change the states relationship between diesel and electric power.
-Will
I think that the point is you have SO such limited range on an electric system, that the counter-current becomes an issue…we wouldn’t give it a second thought on a diesel engine-powered boat…but it HAS to be taken into consideration on an electric-powered boat.
Greg
The issue, as I looked upon the idea, is the density of stored energy. A boat has a finite volume of space within which to pack and store energy, and every thing else needed/desired. At the present time diesel is more efficient at meeting that need on a boat.
Will is correct about the speed through the water being the same. What is pointed out by the video is not the water speed but the distance travelled in relation to the movement (distance travelled) by the storm. With the electric you may be able to travel the 60nm based on the energy stored on board but that leaves you (potentially) with flat batteries just when you need the energy to drive the boat in a storm. The video concludes that diesel is not depleted. This is due to the volume of diesel stored energy is greater in the boat.
I noted the video only breezed by what happens at the point the batteries and the solar cells reach end of life. Choose a point in time. 5 years, 10 or 15? Will we have an ecologically responsible way to dump the old and acquire the new? I say this having just taken a 50 year old engine and rebuilt it. The old parts were not thrown in a dumpster, they were recycled.
Will is correct about the speed through the water being the same. What is pointed out by the video is not the water speed but the distance travelled in relation to the movement (distance travelled) by the storm. With the electric you may be able to travel the 60nm based on the energy stored on board but that leaves you (potentially) with flat batteries just when you need the energy to drive the boat in a storm. The video concludes that diesel is not depleted. This is due to the volume of diesel stored energy is greater in the boat.
I noted the video only breezed by what happens at the point the batteries and the solar cells reach end of life. Choose a point in time. 5 years, 10 or 15? Will we have an ecologically responsible way to dump the old and acquire the new? I say this having just taken a 50 year old engine and rebuilt it. The old parts were not thrown in a dumpster, they were recycled.
He stated his current panels produce 2.5kWh per panel on a good day, and if he increased to 9 panels he could theoretically generate 22kWh in a day. He isn’t saying that 22kWh will get him 66nm, but that with 5-10 days of charging he could generate enough to fully charge the three 30.4kWh batteries in the recommended Oceanvolt setup… and that is enough for 66nm. He is probably accounting for other house loads and days with lower production to get the 5-10 day estimate.
Also, his boat does not have electric propulsion, it has a Yanmar with fuel for 1000nm range. That was the point of the video… Range=Safety. The money he spent was on the solar installation, and that is what isn’t performing as well as in the Med or Caribbean.
After my earlier post, YouTube stepped in suggested I might have been a little rough and started feeding me more Sailing with Thomas videos. About an hour later I learned he does indeed have a Yanmar and caries a lot of extra diesel in his dinghy. It was not clear in the video linked above that he did have a diesel.
As I said earlier, I don't disagree with some of his positions, however, I continue to find his presentations confusing and unnecessarily emotional. It is common knowledge, or should be, that electric motors in a dinghy or a cruising yacht have range and speed restrictions. And no one is really arguing that electric is an equal substitute for diesel.
The core of his argument is electric doesn't work well in places like the ITCZ, there isn't enough battery capacity or solar energy to transit the ITCZ or outrun a hurricane. Well, duh. Mariners have known about the ITCZ, aka the doldrums or horse latitudes, for centuries, Coleridge's Rime of the Ancient Mariner is about crossing the doldrums. As for out running hurricanes, don't sail off shore in hurricane/cyclone season, seems simple enough. Yet, Thomas seems to have a propensity for sailing in and near hurricanes. As for his latest adventure, getting kicked out of Fiji, he has only to blame himself for not getting an extended stay visa before entering the country.
His whole presentation speaks to the adage, "if you can't impress them with your brilliance, dazzle them with BS." He doesn't need to produce the confusing and repetitive graphics. He can make his point simply, logically, and clearly demonstrate it without all the hoopla and passion reminiscent of a nineteenth century snake oil salesman.
A good part of my adverse reaction to his presentation is to the manner of his presentation. He doesn't provide clear and easily understand data and he doesn't allow for the viewer to come their own conclusion and opinion. His conclusion is the right one. Well, Dan and Kika on Uma, might argue otherwise. They have spent 10 years cruising in the Caribbean, Northern Europe, the Med, and above the Arctic Circle on boat powered by OceanVolt (at least for the past few years, prior to that they had DIY motor).
What is most troubling is how this style of presenting information is being used in areas far more common than the esoteric argument about electric powered yachts (truly a third world problem). It can be seen on lots of online advertising, in county fairs, with door-to-door salesmen, and all too often on the nightly news.
What I am asking is as consumers, let's sharpen our critical thinking skills and place more emphasis on logic, reason, and clear data than our passions. Let's hold those who practice this disingenuous style of arguing accountable and call them out. What I am asking of those selling products and ideas is to quit treating us like fools, be honest, objective, and give us the best accurate information available. We can come to our own conclusions.
[/RANT]
I agree with your opinion on his presentation. This is the only video of his I have seen, and I did have to pause and rewatch some segments to figure out what he was trying to say. But I do also agree that you should be able to move the boat 500nm or so, not just for tropical systems, but also avoiding the worst parts of fronts that could ruin your day.
I have followed Uma though. I don’t think their experience does much to disprove Thomas, who I think is mainly talking about long distance sailing beyond the forecast range. Uma did cross the Atlantic, but I think their choice of the fast northern route in August was partly due to concerns about depleting their 15kWh battery bank enroute. Maybe that is why they are so focused on finding a reliable regen solution… Solar alone won’t get them through some longer passages they may be looking at.
Is that even a good argument for a sailboat?
You will probably have no better sailing conditions then the ones in which a sailor is trying to outrun a tropical storm or a hurricane.
The winds will all be going is a good direction for headway away from a hurricane. Only if you are caught in the storm and suffering damage do you need that engine. Of course, there are always circumstances where one can argue for better, faster, longer, more powerful equipment. 60 nm of operation should get you in and out of most harbors, but it may not get you up the Chesapeake, for example.
-Will
He's a YouTuber. It worked at least he got me to watch it and I think that was mostly his intent with the caveat 'don't believe everything the salesman is selling you because if you drink too much of that cure all it could kill you or at least leave you laying at a place you don't want to be and broke'.