5 Myths with Electric Propulsion: Don't Believe Marketing 

That's a good point. I see it as an increased complexity more due to the associated systems in a smaller vessel. If we are just talking about straight electric propulsion, I agree that they are equal to engines in complexity. But with small ships, I see people integrating electric propulsion, diesel generator, shore power, solar charging, recharging from using propeller as a water turbine, etc. That complexity isn't inherent to electric propulsion. But I see that electric propulsion allows us the opportunity to explore the increased complexity and provide a more flexible power plant. (Granted, much of this only applies to small ships and yachts.)

For a lot of small yachts there will be a solar setup with storage battery anyway. Making it 10x bigger just changes the physical size of the parts rather than adding more complexity. But comes with the advantage of being able to run induction cooktops etc so you may not need gas for cooking any more. Then it comes down to whether you have a generator at all. But even if you do, the difference between "we're under power so we're putting hours on a fossil engine" and "it's been six months, we need to start the generator" is significant. "Sailing Uma" don't have a generator, "Rigging Doctor" do, for example. But for commercial operators you're going to need something, whether a nuclear plant or a diesel one (FWIW nuclear are almost all nuclear-electric systems, so you've talked around those boats)

@@DatawaveMarineSolutions why do you say that an electric engine has more complexity? an internal combustion has a lot more complexity and parts and even more complicated electronics. this is a good video from an Engineer about the environmental differences between Cars but much should apply to boats ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-6RhtiPefVzM.html There are disadvantages to Electric engines and batteries but it does not help your argument if you invent reasons without backing them up.

@@akcarlos I like Engineering Explained (EE) but I don't think that video applies to boats. For one, boats not only have to push through (well, most of of the boat) a medium 1000x denser than air, it also has to work against wave drag especially at higher speed. This means that even a few increase in weight means that the consumption increases by a larger factor than in a land vehicle. Also, remember that on larger land vehicles, the problem of the larger battery becomes an issue. See EE and even thunderf00t's video on the Tesla Semi As for complexity, he probably meant the control system. Sure, a combustion engine is complicated but you only have to control it. With battery propulsion, you got to do energy management with hotel loads which is complicated. More so for hybrid systems.

you missed the obvious. you dont use batteries, you use a generator to make the power. makes it a modular system that doesnt have to stop for maintenance when combined with battery. easier to accomodate in the vessel as components arent required to be all in the stern, silent when needed like steaming at night, you can run multiple systems from the battery storage, bow thrusters etc. many benefits.

An all-electric system has many drawbacks, and I think you're operating off a few false premises. For example: size and weight. While electric motors can be lighter than ICE options, we need to compare apples to apples. There are also ICE engines that can be picked up with one hand (think RC car engines), but they don't do us much good for powering large marine vessels. Similarly, the motor in my washing machine can be picked up with one hand, but is not useful for large marine applications. The comparable performance electric motor is going to also be heavy, just like the ICE engine it's replacing. It might be a bit lighter, but we're talking in the same order of magnitude. The real benefit here is that electric motor form factor means we can decouple our sources of power from our use of power (more applicable in hybrid systems than all electric, but still holds true). Next, I want to address your battery statement: batteries are heavy. Lead acid batteries are heavy, but also lithium batteries are heavy. The problem lies with energy density: various lithium chemistries are extremely high in energy density and discharge capacity, but no matter which chemistry you look at, they all pale in comparison to hydrocarbon fuels. This means we need lots of batteries to give us similar ranges as a much smaller weight in hydrocarbon fuels. This is one of the limiting factors in the EV market: the range cap that everyone is running into is defined by size and weight. These modern EVs are using the best lithium chemistries available, and still fall far short of the range and refill capability of hydrocarbons. No matter which battery chemistry you use, you have the unavoidable fact that you do not consume the weight of your energy storage as you use it, and while the cheat code appears to be using batteries structurally to squeeze more capacity in, that introduces a whole different set of nightmares for safety and maintenance. Additionally, lithium battery tech presents a set of hazards that do not really exist with hydrocarbons like diesel (especially in applications where we are sitting in highly electrolytic mediums like sea water). Lithium battery fires are incredibly difficult to manage, and they present a fume/explosive risk that is a poor companion for metal compartments strengthened by sea water. The point of all this rambling is to say that while batteries can make a good emergency or standby store of energy, they are a very poor means of primary storage for large scale or long distance travel applications. The best solutions involve carrying your fuel in sources that are much higher up the density graph: uranium, hydrogen, and hydrocarbon liquids being the obvious contenders. Nuclear electric hybrids are obviously the best but not currently feasible for anything but large naval vessels for a variety of reasons. Hydrogen fuel cells are theoretically great but not commercially ideal and seemingly won't be for a while longer. This leaves us with liquid hydrocarbons. Diesel electric hybrids are already in use in everything from rail and marine to over-the-road trucking (newly in this arena) because of the safety, efficiency, power, speed of refill, etc.

Or a small battery and a large hydrogen capacity, you loterally are surrounded by "fuel" and with sufficient solar and wind energy generation its a cheaper option in the long run

​@@victormiguelmontero136wind is actually the most expensive way to generate electricity, it only affordable due to the government subsidizing it.

The biggest advantage to me: huge house battery.

A electric motor that's heavier than the engine it is replacing lmfao. Grin Technologies just did a sailboat where they replaced a 300 lb boat engine with a 10 lb electric motor with the same power.

yes, this part of video made me wonder what kind of electric motor heavier then diesel. If you add battery weight then it may be same as diesel engine+fuel tanks or even more depending on battery capacity. less maintenance for electric is also a big deal. But the biggest advantage for me is to be able to be off-grid with solar+LiFePO4. You cannot generate more diesel out of thin air if you are in the middle of nowhere and need fuel to run generator to power fridge/frizer/AC/etc. Many boaters need no diesel generator if enough solar&LiFePO4 on board. But still, it's nice to have it as a backup.

I want to say that is not true, because I would like to believe that all engines report a true and accurate rating of their power. But I'm sure some manufacturers cheat the system a little. They should be reporting "brake power" on the engine. That would be the power output, with all the extra loads like alternator and water pump that the engine needs to keep itself running. "Brake power" comes from testing the fully assembled engine on a dynamometer and measuring the power output from the shaft. But, I'm not an engine manufacturer, and the cynical part of me suspects they find ways to adjust the numbers slightly. As to the flatter electric throttle / torque mapping, not sure. In theory, a digital throttle can always be smoother than a menchanical one, simple because we can program the digital throttle to account for changes of the torque curve. But that's not strictly electric motors. I have also seen this behavior on larger outboards that now include digital throttles.

@@DatawaveMarineSolutions Thanks for taking time to reply. Another thought is that certainly 'repowering' with electric is rarely practical, since old hulls, old tricks, high drag. Too many issues for private owners to stomach. But for new builds & hulls built for purpose? Perhaps there's a future there for Naval Architects in that specialty. I worked on a Oram 62ft cat that could reach 10kts on only ~10kw. it was only 8T which helped. Makes for a cheap system, I think there'll be some narrow band of private usages/vessels that work.

@@brentsinger1980 That is very true. I have worked with a number of clients designing new hulls for electric propulsion. The biggest difference: I spend a lot of effort to keep the drag as low as possible.

Indeed - you hit the nail square on the head !

And their torque scales with weight, so a high speed low torque will be lighter than a low speed high torque.

Some of the more interesting technology for near future: ammonia or methanol as replacement fuels for diesel. Both fuels have two important traits. They can be stored as a liquid near room temperature. (Ammonia requires mild refrigeration or compression.). And the molecules contain a lot of hydrogen atoms. Both options still require more development. But the goal would be to use these in a hydrogen fuel cell and power electric motors with the fuel cell. Then we don't need huge batteries.

But is the way they deliver it not different? I am no engineer but I think you need to push that combustion engine a lot to get to the claimed figure?

I agree. The hybrid options have me the most excited. I saw one option from Hybrid Marine UK (www.hybrid-marine.co.uk/). And just recently, I noticed the big engine manufacturers are starting to hint at options that look like hybrid propulsion.

@@DatawaveMarineSolutions Cool. I admit I'm a huge Tesla fanboy. But I feel for Toyota's churlish attitude about battery electric vehicles. I've also got a Prius V - it's a wonderful, reliable, efficient, car. Toyota won the hybrid, invested hundreds of millions in factories and foundries, was positioned to make billions -- and then along came Tesla. It's probably like making the perfect carriage and then Ford comes out with the Model T. I doubt the marine business would be big enough for Toyota, but I'll bet they could make a terrific small boat marine hybrid (especially if they partnered with Yanmar.)

@@DatawaveMarineSolutions Hybrid is a more complex case to optimise since the balance of ICE power, fuel tank, generator capacity, electric propulsion motor power/torque, battery bank size, power output all have to be balanced for the use case. Oh ya, and you have to make the ICE and Electric work with the same prop.

@@WillN2Go1 There are a lot of crazy people who do engine swaps from boats to cars and vice a versa. I think it would need a larger engine and be a smaller vessel but someone may do it at some point on RU-vid.

I looked at the Exro Technologies Coil Driver. Can't say that I have enough expertise to really discern scientific truth from marketing hype. But no, I'm not against electric vehicles in marine. I don't have a problem with electric technology. But it's my job to see the difference between technology and marketing. A lot of electric marketing tries to hide the fact that electric isn't a perfect solution. It does have limitations. And in some cases, those limits don't justify the application to shipping yet. That being said, I see more applications for electric on ships every year, and I look for them myself. We aren't against electric. The problem is just that electric has to compete against internal combustion, which already had 100 years to refine and improve. That is a large head start to compete against.

One more thing: looking at the direction things are going politically, the cost and availability of diesel is a major factor in my plans. There is more crazy shit happening now than I could have imagined just a few years ago. We're heading right into that old Chinese curse "May you live in interesting times." In fact, we're already there.

Lithium ion batteries are temperature sensitive and can self-ignite if they get too hot. You need LiFePO4 (Lithium-iron-phosphate which is not so sensitive. You should also know that any lithium battery's BMS (its battery management system) will refuse to recharge the battery at a very low temperature. The reason is that the battery will get damaged. Teslas, and other electric cars has this problem right now.

Can have a positive effect, well on most boats it’s not. But well some build a stainless steel binimi as an addition. Obviously that’s not making the boat a better sailer too. 😂

I was gonna mention that!

True. I remember that some subs used a steam turbine in place of an electric motor. But all the modern boats do use electric generators and electric motor.

DMS is forgetting the difference in conversion efficiency. An ICE is 30% eff on a good day. So you cannot equate stored energy in the diesel fuel to the battery and call is apples to apples comparison in this case. Nick's weight comparison is FUBAR!

your calcs are wrong. a 12v battle born battery is a case plus a BMS plus cells. you dont factor in all that weight. 16 lifepo4 300ah cells weigh 100kg. use that in your calc.

you numbers are 140% of actual

I wonder if a CAES system will be better. The vessel has to be build around the compressed-air storage units. There're efficient compressors and motors. They work at about 12 atm pressure.

Yup, Drach and Ryan Szmanski discussed those ships along with the problems that came from those, maintenance being one of them. Hence those were not seen in subsequent designs for surface ships. Also, I think the energy density of coal/bunker fuel is way higher than any battery.

Coal powered grid power after transmission losses is about as dirty as regular engine. So even if you charge it with coal power it's ok. Any amount of renewable energy that you get will help.

That last part is far from true. I think this is a common misconception primarily amongst americans. The math says very strongly that the thermal efficiency of combustion based power stations are so much greater than a tiny mobile internal combustion engine that you're always ahead of the game using grid power.

You make a good point on the carbon cost for battery production. I intentionally avoided tracing the carbon footprint for engine production and battery production. That can become a very difficult summation since you need to consider the full supply chain and the CO2 cost for transporting components across a global supply network. It just opens more questions than it answers. I also feel the CO2 cost is not the major issue to use batteries on ships. Weight is the major issue. We simply can't store enough energy at a small enough weight in batteries. They don't even come close to matching current internal combustion. So I still recommend internal combustion on every ship. But I have seen great advantages with the hybrid approach. Use a smaller battery pack combined with a generator or engine. This has the advantage of drastically reducing the time you run the engine, especially with yachts. And for the propulsion, the battery acts as a buffer, allowing you to run the engine at exactly one speed for peak efficiency.

Since when do cars swap battery packs every five years? That's simply a lie. Like there's nothing to unpack there, that's just bottom to top a lie.

Tesla is rated at 1500 full cycles or about 400,000 miles. You do that in 5 years!? You can if you drive a full cycle basically every single day, BUT I call BS on that!

@@zachstine3468 1500 cycles are reached rather quickly if you use it daily

@@razorblade7108 a half cycle does not deplete the battery life the same as a full cycle. driving 1 hour a day is a fraction of a cycle and the battery may go 3,000 or more cycles driving a short amount per day. you should expect 300k miles or more from a tesla battery, which is usually more than 15 years for most drivers and even then, the battery has 80% of the range.

48V x 100Ah = 4800 Wh or 4.8 kWh LiFePo4 batteries have around 180 Wh/kg or 5.55 kg/kWh. 4.8 kWh x 5.55 kg/kWh = 26.64 kg What he is talking about in the video are normal LiPo or Li-Ion batteries for larger boats and ships. Of course they need far more energy. The battery in an electric car already weighs around a metric ton.

@@razorblade7108 180 Wh/kg is closer to lead acid than lithium iron. Tesla's batteries are at 280 Wh/kg today and improving.

@@skirkwood 180 Wh/kg is for LiFePo4 (or LFP, lithium iron phosphate) batteries, which is what the guy with the sailboat is using. Actually the maximum I could find is a little lower at 176 Wh/kg, I rounded it up. Minimum is around 90 Wh/kg for worse/older LFP batteries. LFP has the highest cycle life and still very good energy density as well as safety (it has no flammable electrolyte), it's often used as replacement for long-lasting lead-acid batteries, however it has poorer low-temperature resistance compared to other lithium and lead-acid batteries. Lead-acid batteries have an energy density of 30-50 Wh/kg by the way. Other types of lithium batteries have different energy density, some with up to 265 Wh/kg or as low as 50 Wh/kg. The most common type is lithium nickel manganese cobalt (NMC), which is used in laptops, cars and electronics and has a good mix of power and energy density. Anther common type is lithium nickel cobalt aluminium oxide. Pure lithium manganese oxide and lithium cobalt oxide batteries are less common, as the mix has better properties overall. The latest batteries from Tesla (supplied by Panasonic) are lithium nickel cobalt aluminium oxide ones with an energy density of 260 Wh/kg. Your value might be the energy density of the pure materials, but the end product doesn't reach that. The Tesla Powerwall home storage uses lithium nickel manganese cobalt oxide as it has a higher lifespan. Since lithium iron phosphate batteries need much less rare materials, are safer, have much higher longevity (multiple thousand cycles or 10+ years) and are cheaper, they have reached a pretty high market share despite their lower energy density and will probably replace lithium nickel manganese cobalt oxide batteries over the next years in a lot of applications, except for high performance.

@@skirkwood Lead Acid is 25-35 Wh/kg.

True, same applies to electric trucks: the Tesla semi still pales in comparison with respect to range, fast refuelling and load capacity to traditional diesel semi-trailer trucks.

I look forward to your concise video with a thorough comparison between electric motor and combustion engines.

Torque is not power. Power is force times speed, or torque times RPM in this case (in different units of measurement). Electric motors reach peak power at max RPM, while combustion engines reach it either at max RPM or some point before, depending on how the torque output is at higher RPM. There are also different types of electric motors and controllers changing their characteristics. One thing that can be said is that they never have full torque on the first rotation (the controller needs to get the motor spinning first) and the torque drops off at higher RPMs, it does not stay constant. Some combinations of motor and controller can keep the torque quite constant up until some RPM until it drops off quickly at higher RPMs, others will drop off smoothly from start to end. I don't see how high starting torque would benefit a boat honestly. Accelerating the propellers quickly will cause cavitation and therefore increased damage on the propellers, you need to increase their speed gradually anyways. Usually this is also done automatically by the controller to reduce the starting torque and accelerate more softly, also to reduce stress on mechanical components.

@@razorblade7108 lol. yes mate. i know all that. why would you assume rpm would not change?? high torque gives you the ability to lower rpm and increase prop pitch and diameter. same propulsion for less friction and noise.

@@DatawaveMarineSolutions why?... firstly im not narcissistic enough to spend my precious time trying to get likes on youtube. secondly there are already 1000 videos on the topic. maybe you should look one up. and thirdly i have actually converted many ICE to electric vehicles and know first hand the comparisons. not just a white board and a text book. if you weren't so busy trying to get likes and attention with your time you might be able to do some real engineering. not just talk about it.

@@freelectron2029 Torque is turning against resistance, but in an electric boat or ship the resistance is water viscosity and inertia as you get going. In a car, resistance is the weight of the car. They’re totally different engineering arenas. Ships need power, torque times rotation velocity. Aircraft are like ships; air resistance to turning the prop is negligible until it’s generating thrust from higher velocity air motion. Again power is what matters there.