Sail boat engine choice - electric or diesel

[newhaul]

Originally Posted by wingssail

Correction: to move our 43' liveaboard sloop with ourselves, provisions, spares, and all of our worldly possessions aboard, 500miles at 6.2kts requires only 60 gallons of diesel, not hundreds of gallons.

And, Mr Prichard, maybe you can move 2-3 knots with 1.2-15kw, which if I am not mistaken, is about two HP, but I'd say that in a seaway or against a headwind, you will need a bit more power, which will deplete your batteries a bit faster.

For example a situation common in our neighborhood is the rounding of Cabo Corrientes against wind and tide. We'd be sailing ourselves but most cruisers hereabouts will be motoring. It is not uncommon for them to come in telling us that they could only go 2 knots at full power, with their 45hp 4JH engines.

Check my math, but to do that with electric you'd need about 35kw of electric engine and about 105kWhr of batteries.

Basically electric power will remove that Cabo Corrientes rounding from your list of options. You just can't do it. Most likely you will respond by saying you don't want to anyhow. What else could you say?

Now, complexity: You have 1700 lithium batteries hooked up in a in 4 6S77P set up. You should a BMS (or several) which can open the bank relay (so you must have bank relays) in the event of a high or low voltage condition for that cell, you should have thermal cut-offs for each cell in case of a dangerous high temperature situation and a battery status monitor to sound alarms if the overall voltages get out of hand and to keep track of the state of charge. There should be protection against battery dumping by the BMS while engine charging to protect your alternator and some clever charge splitting to keep an engine starting battery charged when it has different charge profile. None of this addresses the shore power or solar power charging management.

None of ALL of that addresses monitoring and management of this whole system. (say a cell or a few drop off line, how do you know this happened? or a thermal cut-off trips?). Problem diagnosis becomes a job for a competent and maybe brave electrician. Is that you? If not, where do you g=find one in Papua New Guinea?

Instead, the DYI electric boat conversion guy just hooks it all up and assumes it will last 10 years without any failures anywhere among the 2000-4000 connections and electronic devices included in the system. It starts to make the diesel look sort of simple, and safe.

Electric is coming, but it is not here yet unless you overlook quite a few limitations and complications.

Just thought I would add that the average 2 cylinder marine diesel has just over 300 total parts including the bolts. 99% of which will not wear or cause an issue in the life of the engine. In most cases that is measured in 1,000's to ten of thousands of hours. With 3 simple things . Clean fuel, clean oil , and clean air.

[MichaelPrichard]

Originally Posted by newhaul

That is not what I stated so don't put words into my mouth.
I am referring to the number of connections in your specific bank.

I am running lfp myself but alot fewer connections. My house bank consists of 4 250ah cells in a 1p4s for 12v nominal. All bolted. You are all electric spot welded and hard pounding vibrations will eventually cause them to fail . ( There is no flex) mechanical engineering 101.

My apologies if I misunderstood you. I, too, love the simplicity of those big LFP cells but my budget didn't allow that for the amount of power that I needed/wanted, and used Tesla modules are about half the cost of even used LFP per kWh, at least when I got mine, comparing to used Nissan Leaf cells. However, I've got fewer connections per pack/volt since each module is 24V nominal vs. 3.7V, only adding connections with subsequent parallel strings. The 888 welds per module in the Tesla pack are engineered for far higher shock loads of a car than they'll ever see in a boat, so I don't consider those a risk. I'm a mechanical engineer by trade and have carefully considered and studied all of the components in my system. It's far from perfect, I'm sure, but if those spot welds can withstand the auto environment, I've got a lot of confidence in the much gentler conditions aboard our boat, even in a storm. If you've never seen one of these modules, they're a marvel of engineering, each one at least 50% wrapped by the largest custom designed heat pipe I've ever seen (and I used to design those for Apple). I also suspect that they've compensated for the inevitable flex/shock of the auto environment by the length of wire between the cell and the plate, something around 6-12mm if memory serves.

[MichaelPrichard]

Originally Posted by wingssail

Correction: to move our 43' liveaboard sloop with ourselves, provisions, spares, and all of our worldly possessions aboard, 500miles at 6.2kts requires only 60 gallons of diesel, not hundreds of gallons.

I was speaking rhetorically about the fact that long distance cruisers will often have hundreds of gallons, not stating those were required for that particular distance. Apologies if I was unclear.

Originally Posted by wingssail

And, Mr Prichard, maybe you can move 2-3 knots with 1.2-15kw, which if I am not mistaken, is about two HP, but I'd say that in a seaway or against a headwind, you will need a bit more power, which will deplete your batteries a bit faster.

No doubt.

Originally Posted by wingssail

For example a situation common in our neighborhood is the rounding of Cabo Corrientes against wind and tide. We'd be sailing ourselves but most cruisers hereabouts will be motoring. It is not uncommon for them to come in telling us that they could only go 2 knots at full power, with their 45hp 4JH engines.

Check my math, but to do that with electric you'd need about 35kw of electric engine and about 105kWhr of batteries.

Basically electric power will remove that Cabo Corrientes rounding from your list of options. You just can't do it. Most likely you will respond by saying you don't want to anyhow. What else could you say?

I guess you've answered your own question with the statement "We'd be sailing ourselves...". But also note that I didn't design my system for that other cruisers monohull, but rather our more efficient and more easily driven cat. When we get to doing long distance cruises, we'll likely increase our battery capacity or have a backup generator, either of which will still be lighter than our twin diesels. The 4 modules I've got each weigh only 55lbs, or 220lbs for 21.2kWhrs which happens to be a quarter of a typical 85kWh Tesla Model S. We can easily accommodate the remaining 12 modules (when $$$ allow) which would likely give us the capacity needed above (when corrected for a catamaran) for less than 1000lbs and we'd still be below our original weight.

Originally Posted by wingssail

Now, complexity: You have 1700 lithium batteries hooked up in a in 4 6S77P set up. You should a BMS (or several) which can open the bank relay (so you must have bank relays) in the event of a high or low voltage condition for that cell, you should have thermal cut-offs for each cell in case of a dangerous high temperature situation and a battery status monitor to sound alarms if the overall voltages get out of hand and to keep track of the state of charge. There should be protection against battery dumping by the BMS while engine charging to protect your alternator and some clever charge splitting to keep an engine starting battery charged when it has different charge profile. None of this addresses the shore power or solar power charging management.

None of ALL of that addresses monitoring and management of this whole system. (say a cell or a few drop off line, how do you know this happened? or a thermal cut-off trips?). Problem diagnosis becomes a job for a competent and maybe brave electrician. Is that you? If not, where do you g=find one in Papua New Guinea?

Instead, the DYI electric boat conversion guy just hooks it all up and assumes it will last 10 years without any failures anywhere among the 2000-4000 connections and electronic devices included in the system. It starts to make the diesel look sort of simple, and safe.

Electric is coming, but it is not here yet unless you overlook quite a few limitations and complications.

Indeed, you appear to have done your homework! You should convert to Electric yourself. We have all of the above stated hardware and then some, although we don't have alternators, so no "dumping" required, and also no starting battery as there's no engine. We do have a 12V AGM battery to run all of the traditional boat systems/fridge/lights if something should happen to the main pack. All charging is controlled by the central BMS which itself communicates with each modules internal BMS, each of which has a number of thermocouples monitoring temperatures of all the cells. The BMS controls access to the pack via both high power contactors and manual switch over-rides. The Victorn Quattro Inverter/Charger takes it's charging queues from the BMS and regulates the MPPT charging as well. This BMS even includes a "storage mode" to limit charging to only 60% of capacity to minimize long term wear when not using the boat. The system of BMSs maintain a maximum cell/cell hysteresis of 40mv above which a warning will be set.

As to the requirement that one must be a "brave electrician" before attempting to maintain such a system, it is certainly worth noting that even 48V of electricity and lithium cells in particular do require extra care, no question, and for the moment, unless one has such knowledgable friends or professionals, this isn't for everyone, but progress isn't typically made by "experts" in fields that don't yet exist...

[newhaul]

Originally Posted by MichaelPrichard

My apologies if I misunderstood you. I, too, love the simplicity of those big LFP cells but my budget didn't allow that for the amount of power that I needed/wanted, and used Tesla modules are about half the cost of even used LFP per kWh, at least when I got mine, comparing to used Nissan Leaf cells. However, I've got fewer connections per pack/volt since each module is 24V nominal vs. 3.7V, only adding connections with subsequent parallel strings. The 888 welds per module in the Tesla pack are engineered for far higher shock loads of a car than they'll ever see in a boat,.

I have actually seen the shock loads on a boat that literally tore steel apart. And I'm talking plate not tin .

But just one bashing from LA Paz to San Diego will change your mind about the shocks a boat can be subjected to rather often. I sencerly hop your boat doesn't have issues when it is subjected to that . Trust anything that can fail will fail at the most inopertune moment .

Plan accordingly

[wingssail]

Originally Posted by newhaul

I have actually seen the shock loads on a boat that literally tore steel apart. And I'm talking plate not tin .

But just one bashing from LA Paz to San Diego will change your mind about the shocks a boat can be subjected to rather often. I sencerly hop your boat doesn't have issues when it is subjected to that . Trust anything that can fail will fail at the most inopertune moment .

Plan accordingly

Well, he has about 2000 points of failure on his system, so I am sure that eventually he will experience that inopportune moment but I am also sure that he has the diagnostic skills and system displays so that in that event he can determine exactly what has failed and has a few hundred spares to effect a repair, even at sea (and perhaps a automatic welding machine for those battery connections) as soon as his Victron display tells him which one failed.

[s/v Jedi]

Originally Posted by wingssail

Jedi, I don't know who coined that phrase, but I have used it. It's not a joke, and I'm not clueless as to why people do that to their boats (install massive arrays of solar over the transom). I just think it is not pretty and it is harmful in multiple ways to the sailing ability of the boat (of course it improves the electrical power generating ability of the boat). There is the trade off and it is one I would not make.

I think that people who value the sailing performance of their boats, and value the beauty of them, can still know what sailboat cruising and life are all about. For those who feel that a large platform filled with solar panels hanging over the backs of their boats is beautiful, and has no effect on the sailing performance; they have a different aesthetic than I do, which is fine, I'm used to being an outlier.

Really?! So you have no bimini and no dinghy hoisted up in davits either? Because those would be the same kind of ugly and the same negative effect on performance. Do you deflate and fold your dinghy to store it belowdecks in those silly bags? How do you sit in the cockpit under the blazing sun without getting skin cancer?

People who put solar panels up, put them on top oftheir bimini or on the stern above the dinghy hoist. Either way, that horizontal surface is already there and they utilize it to put solar on top. Yesterday I measured to see if I can put even bigger panels up there and found that with the 67” long panels I’m planning for, the dinghy still sticks out further.

The rest of your response shows you really have no idea what it is about. You write that people think their solar array add to the beatification of their boats and if I believe you to be serious, then self reliance and preparedness must be alien words to you

[wingssail]

Here we go again, more expressions of self perfection by a person who knows everything and has no conception that other views could possibly have any validity. OK I'll byte even though I know how it will end up: Jedi is right and anyone who disagrees is an idiot, which he will be quick to say in no uncertain terms.

Originally Posted by s/v Jedi

Really?! So you have no bimini and no dinghy hoisted up in davits either?
We have no bimini. When sailing, if it is hot, we rig an awning for shade, we have several. A bimini just won't work with end-of-boom sheeting and it would interfere with the kind of racing we do and we love the freedom to be able to instantly move around on the deck of our boat without interference of braces, frames, tubes and guy lines, and we like a clear view of the sky and sails. Sailing is an outdoor activity.

We do not have dingy davits. For a boat of our size it is one thing I would never do, not just for looks, but the weight aloft, weight in the ends, windage, and risk in heavy weather puts me off of that. Our dingy can be hoisted forward quicker and easier than most people can hoist theirs on the davits aft, and swung onto the foredeck in a instant.

Because those would be the same kind of ugly and the same negative effect on performance. Yes, exactly.

Do you deflate and fold your dinghy to store it below decks in those silly bags? Absolutely, the motor too.

How do you sit in the cockpit under the blazing sun without getting skin cancer? addressed

People who put solar panels up, put them on top of their bimini or on the stern above the dinghy hoist.
Most do, but there are many locations more suitable; ours are mounted on the side railing of an extended pushpit, easily adjustable for sun direction, and clear of all shadows most of the time and a good place to set my scotch when using the adjacent BBQ.

Either way, that horizontal surface is already there and they utilize it to put solar on top. Yesterday I measured to see if I can put even bigger panels up there and found that with the 67” long panels I’m planning for, the dinghy still sticks out further.

The rest of your response shows you really have no idea what it is about. You write that people think their solar array add to the beatification of their boats and if I believe you to be serious, then self reliance and preparedness must be alien words to you
Apparently I don't have the same idea of what "it" is all about as you do, and apparently you think yours is the only correct idea.

I never said, by the way, that I believe any owners add solar arrays for beautification of their vessels, only that, in my view, that addition detracts from the beauty, but people do it anyway because they value the utility of a lot of solar more than they value retaining nice lines of the boat.

And I have no idea how you can conclude anything at all about my self reliance or preparedness. We have lived aboard and cruised this vessel for 34
years and have been as self reliant and prepared as anyone I know, as my sailing and cruising record shows, much of it in places far beyond the range of outside help. That says more about self reliance and preparedness than my unwillingness to add a helo pad on the stern of my vessel.

[s/v Jedi]

Originally Posted by wingssail

Here we go again, more expressions of self perfection by a person who knows everything and has no conception that other views could possibly have any validity. OK I'll byte even though I know how it will end up: Jedi is right and anyone who disagrees is an idiot, which he will be quick to say in no uncertain terms.

You may have missed the wink, but I don’t think you did because you are pulling people’s legs in this thread so you are well aware that I was even without noticing the wink. However, you resort to personal attacks on me that do not allow room for tongue in cheek; how you manage to do that while at the same time accusing me of doing it, while I don’t, is telling. You are disqualified for further discussion.

[newhaul]

Originally Posted by s/v Jedi

Really?! So you have no bimini and no dinghy hoisted up in davits either? Because those would be the same kind of ugly and the same negative effect on performance. Do you deflate and fold your dinghy to store it belowdecks in those silly bags? How do you sit in the cockpit under the blazing sun without getting skin cancer?

People who put solar panels up, put them on top oftheir bimini or on the stern above the dinghy hoist. Either way, that horizontal surface is already there and they utilize it to put solar on top. Yesterday I measured to see if I can put even bigger panels up there and found that with the 67” long panels I’m planning for, the dinghy still sticks out further.

The rest of your response shows you really have no idea what it is about. You write that people think their solar array add to the beatification of their boats and if I believe you to be serious, then self reliance and preparedness must be alien words to you

Ok bit o fun and this is personally not in general. ( But a good idea none the less)

First off dingy on davits . Nope always on deck for passages and towed for short hops. ( Davits are not in my opinion a good place for dingy on passages . One breaking wave and you loose the dingy and take severe damage to the boat. ). Yes I do deflate the dingy and store on deck rolled up against front of mast.

Sitting in cockpit underway that's what light white shirts and a wide brim hat is for.
At anchor a boom tent.

Solar underway 2 100watt panels on sides of pushpit. At anchor I have 2 100watt flex panels that reside on boom tent.
Also 400 watt airx marine 400 wind generator. As needed.

If I need more power to charge my lfp bank I have planned for a 135 amp alternator will charge my bank in about an hour to a point the solar will finish the job . ( Have not needed to charge with mains but can if needed. )
All that being said let's all meet up over a sundowner and BS each other with our sea stories.
After all isn't that's what this life is all about.

[seandepagnier]

When I sailed from indonesia to south africa I was becalmed for a total of 20 minutes. I averaged 6 knots the whole time. Most of the time there was a lot more wind than I wanted, and the brief calm was a relief.

From south africa all the way to the United States I never was becalmed, and always had sufficient wind.

The only time I was becalmed far from land for more than a few hours was in the pacific crossing for 3 days from mexico to cook islands. In a 44 day passage becalmed for 3 days is not a big deal, but a slightly faster (and most boats are) boat would have more than compensated for this difference.

Many other sailors agree with me: for ocean passages, engines are not useful.

Its basically only coastal passages with significant chance to get becalmed for days and in this case you don't need this huge range anymore.

Originally Posted by wingssail

And, Mr Prichard, maybe you can move 2-3 knots with 1.2-15kw, which if I am not mistaken, is about two HP, but I'd say that in a seaway or against a headwind, you will need a bit more power, which will deplete your batteries a bit faster.

Motoring against the wind again? Why do you do it? The boat is more comfortable sailing.

I often see boats here sailing, and other boats motoring. The ones motoring could be sailing, but they aren't. The other day, a boat got towed in, in perfect conditions (10 knots dead run) to sail in to the harbor. Another time I asked someone why he doesn't sail into the dock when the wind was perfect (again 10 knots run) to do it, and he has no answer. It seems to be from lack of experience in sailing to docks, and he will never get any!


It seems pretty clear the ones "needing" to motor hundreds of miles are the type who simply do not utilize the available wind power.

There just isn't enough energy to go around for all 7 billion people to be doing this type of thing anyway, and it's surprising how entitled a lot of people think they are. Take the cruisers who take seabird eggs and other endangered wildlife as their _right_ for example, when billions of people are consuming no fossil fuels at all!

Originally Posted by wingssail

. I was happy to have that kind of capability when crossing the Pacific although we didn't need to use it.

Thanks for pointing out, you just didn't need this range.

Modern boats don't get stuck in the doldrums for more than a few days because they can sail upwind in relatively light winds. This wasn't so easy with the old sailing ships.

The ones who disagree will never be convinced. They don't want to change, they are diesel junkies, addicted to consuming far more than their fair share of energy in this world. They don't want to wait for the right tide or bother removing the sail cover to go a few miles. This is not a justification against electric propulsion in any way.

[seandepagnier]

For sustainability, electric economy is not good enough to completely save us with current technology, but it gives us 10 times longer to deal with the problem.

Because lithium batteries can be recharged thousands of times and then be recycled, and solar panels the frames and glass can be reused and the cells recycled, the environmental impact to use the same amount of energy is about 1/10th diesel power. If we then use 1/10th the energy as well, we can reach a trajectory of a sustainable future, but we have to do both.

To actually do this, the motor is only used when there is 5knots of wind or less, and then to power the boat 2-4 knots.

If you do not have a combustion engine and are in need of an autopilot, you should contact me. I can offer a half off discount ($80 for a new autopilot) with features like no other.

If you don't have any propulsion at all besides oars, this is to be revered above electric users. I can offer a free autopilot (if you crossed an ocean on the boat already) as I too fell in this category for many years until just a few weeks ago with my electric motor.


The question should not be "electric or diesel" but "electric or oars"

[MichaelPrichard]

Originally Posted by seandepagnier

For sustainability, electric economy is not good enough to completely save us with current technology, but it gives us 10 times longer to deal with the problem.

Because lithium batteries can be recharged thousands of times and then be recycled, and solar panels the frames and glass can be reused and the cells recycled, the environmental impact to use the same amount of energy is about 1/10th diesel power. If we then use 1/10th the energy as well, we can reach a trajectory of a sustainable future, but we have to do both.

To actually do this, the motor is only used when there is 5knots of wind or less, and then to power the boat 2-4 knots.

I've actually been toying with the idea of mounting (either permanently or temporarily) a large 2-5kW wind turbine (or two) somehow to the mast, or between the mast and the shrouds, if 2 are used; these would be rigidly aimed forward, so no need to have pivot clearances. The idea would be to allow "sailing" directly into the wind in a manner similar to what this guy did some time ago:

https://www.youtube.com/watch?v=IzGCYaJbf0A

but using the electric propulsion. At anchor, it (they) would also provide envious generation capacity since they'll likely start spinning at lower wind speeds than typical smaller units. For all other points of sail, they'd be locked or removed and the sails would be used normally. This is likely the definition of "thread creep" and I intend to start another thread, but just noting it as a possible category for using the electric motors to enable true upwind "sailing".

[wingssail]

Originally Posted by seandepagnier

The ones who disagree will never be convinced. They don't want to change, they are diesel junkies, addicted to consuming far more than their fair share of energy in this world. They don't want to wait for the right tide or bother removing the sail cover to go a few miles. This is not a justification against electric propulsion in any way.

Disagree with what? That it can work for some people? No-one disagrees with that. That we should immediately take out our diesel and install lithium batteries and an electric motor? You are right, unless big changes happen with electric storage we will not be convinced. Besides your contraption is not a practical model of how it can work for people on real cruising boats. Show us a real working, full size, model.

Sean, you are definitely a purist, and right in step with the times at least in your point of view although I don't know if you really walk the walk.

However, though maybe more of us should be, not everyone is like you. I am not such a purist but I don't consider myself a diesel junky addicted to consuming more than my share of energy either, so that is an unfair charge.

I have fuel usage records going back to 2005, but taking the last 10 years as a sample, we used 495 gallons of diesel, or approx. 49.5 per year. We accumulated 2332 engine hours, so that is avg .21 gal per hour, the vast majority of that was for charging the house batteries during our 1700 days away from the dock, either on passage or at anchor. This is around around .28 gal per day for battery charging (it is supplemented by solar).

During this period of 10 years we left the dock or got underway from anchor 369 times. We covered over 14,000 nm of ocean passages during this time, and countless day sails. The number of hours, and therefore the number of gallons, used for powering is insignificant, probably 10% or less of the total fuel we used, but several of those motoring occasions were for several hours at a time. Northward through Central America is a prime example. In three months we averaged 12 hours per day of wind (over a 24 hour period, half of it was at night), usually less than 7 knots.

Of course we could have accomplished all of this with electric power, and, if we chose, added sufficient solar panels to keep our house batteries up on some of the days (sunlight is not always available). My opinion is that this would be detrimental to our preferred use of the boat which is as a great sailing boat, not a floating solar farm. That, and for reasons of preference (to have the capability to motor when we need to), is why we don't think that we'd like to give up our diesel engine just yet, not mentioning the complexity of the battery system which I addressed elsewhere.

So, if 49.5 gallons of diesel per year in our boat (we use that much gasoline in three months in our car, how about your car Sean?) for full time cruisers and our personal need for an engine for reserve motoring capability makes us environmentally selfish, then I have to plead guilty.

All of these numbers are recorded in our log which is available of inspection by anyone at Log Book Pages

[seandepagnier]

Originally Posted by wingssail

Disagree with what?

That electric is already sufficient for everyone. It is also getting better all the time.

Originally Posted by wingssail

So, if 49.5 gallons of diesel per year in ur boat (we use that much gasoline in three months in our car, how about your car Sean?)

I have never owned a car and I refuse to even ride in one. I dislike cars almost as much as powerboats.

I don't ride buses either. I use bicycle (few thousand miles a year) and walking as my only land transport. The battery pictured was actually for my bicycle I have yet to try it out so far I only use pedaling. I typically pedal 100-120 miles a day for several days in a row as needed to visit places.

49.5 gallons seems a lot to me. I used less than 2 gallons of alcohol a year (several years less than 1) over 10 years as the only fuel but I managed to eliminate this recently. I mostly use a solar oven now, and before I used wood (and will again when the season changes). In any case 49 gallons doesn't cost much you could consider the benefits of vegetable oil since the cost difference of 49 gallons is not much.

[S/V Adeline]

Anyone who has had to navigate the Intracoastal Waterway in the US knows that some form of reliable, sustainable, and constant propulsion is required. 1,200+ miles at 20 miles per day is unrealistic. Finding a place to recharge every 20 miles is unrealistic. Until electric can offer sustainable power for emergency situations it is unrealistic to claim it would work for everyone.
One day electric propulsion will be a viable solution, it just isn't there now.