Inboard engines and a changing world

[Adelie]

Originally Posted by Lake-Effect

There's no denying the simplicity and reliability of a basic diesel turning a propshaft, but at least in theory, an ICE generator, battery-bank and electric motor should be more efficient. ICEs are most efficient when they're optimised for running at one speed and turning a steady load (eg a generator), and electric motors are efficient and capable over a wider range of speeds and loads.



This (minus the batteries) is how most diesel locomotives and many big cruiseliners are powered. I don't know whether this sort of system yields enough efficiency yet at "sailboat" size to justify the complexity and cost.

Diesel electric is used in trains, ferries and cruise ships for reasons other than efficiency.

Trains use D-E for starting, they get full torque at zero velocity.

Ferries use it for the quick shifting forward to reverse and to a lesser extent the quicker change in thrust levels.

Cruise ships use it for similar reasons: they need to pull into port without tugs so they’ve made a whole range of design choices in pursuit of manoeuvrability, including electric drive, at the expense of efficiency.

If it were more efficient than direct drive then cargo vessels would be using it too.

[Mike OReilly]

Originally Posted by Chotu

You and I aren't talking any distance apart at all. We're saying the same thing. A boat independent of land.

Agreed.

Originally Posted by Chotu

Other than HVAC, this is absolutely possible on electric only powered by solar. I have enough space for 2.8KW of solar on my cabin top. Half of that would do just fine to power refrigerator/freezer, autopilot, microwave, induction cooktop, electric hot water.

Just to be clear (and you've probably already said this) ... you're not talking a monohull sailboat here, right? There's no way you can mount 2800 watts on any modest sized monohull I'm aware of. The most I've heard of is 1000 to 1200 watts. I'm pretty much maxed our with my 400 watts.

Originally Posted by Chotu

I have outboards already. Those are modular engines you can replace with whatever the flavor of the decade is, so I'm covered there.

I once saw a catamaran retrofitted with an amazing electric engine system. It had a huge solar array on its cabin. Not sure how big it was, but it was big. It still could not keep up with the demands, but that might have been due to poor design (Gord May will recall the boat I'm talking about).

Originally Posted by Chotu

Finally, a good sailing boat is the most important of all, so the engine doesn't need to be used as much.

Yeah... that's always the theory. It's harder to live this way in practice, but some do.

Originally Posted by Chotu

We are actually talking about the same thing. I'm just looking toward the future with an eye on what's trending with power/energy. And it's not diesel. I even see a ton of diesel shops up for sale along with gas stations. It's a limited space. It's closing in and it's happening faster and faster.

So, I'm making a boat that has no mission critical dependence on land (read fuel docks and propane filling stations). It's the future-proof version of exactly what you're describing.

There's no doubt that civilization must give up on the mass use of fossil fuels. Either that or the planet will give up on our civilization . I just don't see an electrical equivalent to the energy density of diesel engines for small vessels like mine right now. It will come, but it seems a long way off to my eyes.

[a64pilot]

Any, at least Yanmar anyway engine has in its engine manual the efficiency curve or power made vs fuel consumed.
You can do your own calculations, and the fuel savings it’s as large as you would hope, but the one thing you cannot calculate is how much shorter a life does this engine have because it’s being loaded much higher than normal? There is a shorter life I can assure you.
Aircraft engine TBO’s are usually between 1400 hours to I’ve seen as high as 2400 hours, but that’s unusual, most seem to fall between 1500 hours and 2,000.

Now that’s not because aircraft engines are junk, it’s because they are operated usually around 75% power, and for short durations full throttle operation.
It’s not uncommon for one that is operated at lower power settings to last much longer, oil change interval and how hard it’s run and frequency of operation seem to be the life limit drivers, with how hard it’s run having a large effect.

Boat engines are usually run with fixed pitch props, and fixed pitch props usually don’t load and engine all that hard except at full throttle, which is usually rarely used on a boat, and for those reasons more than 5,000 hours isn’t all that uncommon.
The myth of you have to run the snot out of a Diesel to make it last is just that, and to see it, look at Sportfishermen to see how long the ones that run them 100 off the top last.

[Bill Seal]

Reality check...
Electric motors are about 90% efficient, no "orders of magnitude" improvements available.
Absolute solar power on the Earth's surface is about 1KW/Square Meter x 6hr/day
Solar panel efficiency is limited to about 30% for reasons due to the Laws of Physics (which I don't fully understand - I don't really understand Entropy, either). No "orders of Magnitude" improvements here either.
Just my 2 cents,

[Adelie]

Originally Posted by a64pilot

Any, at least Yanmar anyway engine has in its engine manual the efficiency curve or power made vs fuel consumed.
You can do your own calculations, and the fuel savings it’s as large as you would hope, but the one thing you cannot calculate is how much shorter a life does this engine have because it’s being loaded much higher than normal? There is a shorter life I can assure you.
Aircraft engine TBO’s are usually between 1400 hours to I’ve seen as high as 2400 hours, but that’s unusual, most seem to fall between 1500 hours and 2,000.

Now that’s not because aircraft engines are junk, it’s because they are operated usually around 75% power, and for short durations full throttle operation.
It’s not uncommon for one that is operated at lower power settings to last much longer, oil change interval and how hard it’s run and frequency of operation seem to be the life limit drivers, with how hard it’s run having a large effect.

Boat engines are usually run with fixed pitch props, and fixed pitch props usually don’t load and engine all that hard except at full throttle, which is usually rarely used on a boat, and for those reasons more than 5,000 hours isn’t all that uncommon.
The myth of you have to run the snot out of a Diesel to make it last is just that, and to see it, look at Sportfishermen to see how long the ones that run them 100 off the top last.

Comparisons to aircraft are poor. Aircraft engines a redesigned to minimize weight at the cost of more frequent maintenance. Also with a few exceptions they run gasoline not diesel.

[daletournier]

Originally Posted by newhaul

there actually have been good strides wrt lithium tech in the last 5 years alone . The biggest is in safety. The smallest ( and IMO most needed ) the advances in energy density.

That's sort of my point, an electric motor is an electric motor therefore it really comes down to energy storage, or storage density, which is still a long way off being great from what I see. Nothing much has changed.

But I admit I dont look into as much as others here , best I sit on the sidelines.

[roland stockham]

In my opinion much of this discussion both on the posibilities for solar power on boats anthe more general comments on global energy production 'puts the cart befor the horse'. What has to change is not a revolution in power generation but a reduction in consumption. Since the early part of the last century power consumption in industrialized countries hasrisen expotentially and it is largely that rise that is at the rout of the environmental crisis. We can tackle the problem without a revolution in power production through a combination of modist technological development and major reduction in consumption and only that way. Technology will not produce a battery that will power a 50ft boat at 9kn for a couple of hundred miles. To quote Scottie "ye canno change the laws of physics"

But look at our consumption. A typical house has a 200a supply at 220v, thats 44Kw per hr. I am currently putting up a complex of 4 offices, computer lab community laundry and youth center that will be power 80% of the year bu 7kw of solar panels.
On boats I keep seeing people discussing the need for lithum batteries to maintain 2-400 a/hr per day. My boat has 200w of panels which is plenty (but I do burn 1g/m of kerosene for cooking.
Modern electronics are already at a point wher nav gear lighting and entertainment/computers should consume negligable amounts. So where does all the power go. The first big issue is waste. Currently if you look at all industrial countries estimates are that we waste anything up to 60% of the power we generate. Iam not talking about leaving the lights on but things like food waste. Food production is a massive C02 contributer but more than half the food produced is not eaten.Also substantial amounts of food are is shipped long distances. People in canada eat food from California, Austrailia etc burning more diesel in transport than it cost to produce the food.
Transort is anothe big user but look at typical cars and trucks. We use massivly overpowered vehicle, cars capable of twice the legal speed limit and trucks that cruise at 100km/hr fully loaded. If all vehicles were designed with a top speed of 90km/hr it would reduce fuel consumption massively. Same applies to boats, if it takes 2g/hr to run your boat at hull speed then slowing down by 20% would cut fuel use to about 1/gal/hr
Heat and cooling are also massive potential energy savers turn the thermostat down by a few deg and put on a jumper and you can halve fuel consumption. Same with A/C it is a nice luxury but a well desined living space with some fans is perfecty practical in most places. If no drop the temp the min needed, we can all get used to working in 35deg, even me who is happiest with my feet in the snow. One heating solution I have not yet seen on a boatvis a heat pump. Using keel cooling it should be at least 60% more efficent that any other system.
So solution is to chill out, take more time to get places and use what we need not create social status by the size of our property and how much we consume.
The problem is that we live in a commercial world where growth is god and if we all did this it would collapse the world economy so that is were we need to change.

[Lake-Effect]

Originally Posted by roland stockham

In my opinion much of this discussion both on the possibilities for solar power on boats and the more general comments on global energy production 'puts the cart before the horse'. What has to change is not a revolution in power generation but a reduction in consumption.

We need them both; more efficiency and conservation from the current 1st world energy users, and sustainable, carbon-neutral energy alternatives so the developing world can make less of a mess as they catch up to us.

[GordMay]

Originally Posted by daletournier

... an electric motor is an electric motor therefore it really comes down to energy storage, or storage density, which is still a long way off being great from what I see. Nothing much has changed.
But I admit I dont look into as much as others here , best I sit on the sidelines.

Indeed.
There are significant differences in motor efficiencies - past, present, and future.

[newhaul]

Originally Posted by Lake-Effect

We need them both; more efficiency and conservation from the current 1st world energy users, and sustainable, carbon-neutral energy alternatives so the developing world can make less of a mess as they catch up to us.

and that leads us to nuclear as the best mid term alternative.
Primarily thorium SMR and molten salt SMR tech.

[newhaul]

Originally Posted by GordMay

Indeed.
There are significant differences in motor efficiencies - past, present, and future.

do tell
The current 48v brushless dc motors are between 92% and 95% efficient .
Do you have any inside data showing how to improve that level of efficiency?
It is basically against the laws of physics and thermodynamics to get any better .

[Pizzazz]

My view is that electric makes sense for the vast majority of marina bound sailing vessels today but the perception that we have is that we need the range (even though we rarey use it). Long run, I believe that if sailing vessels are engineered around electric (batteries in the keel or bilge), it would make a big difference in viability. Especially if there is a storage repurchase option so that when at the dock you can “lend” your storage to the grid. It will take time though.

Other than propulsion, I think electric is viable today for cooking on board (especially with a smart pressure cooker) and even for the grill. It is also a great solution for dinghies (with a foldable solar panel). It is not that good for heating space or water.

For typical small motor vessels, diesel is by far the best choice today, but for large, displacement cargo ships - I am not so sure. Someone needs to do the math of the energy required to move a cargo ship across the ocean and the different ways to provide this energy (batteries, gas turbines) and I am not sure which way is more efficient. It would not be as clear cut as it is for small vessels though.

SV Pizzazz

[newhaul]

Originally Posted by Pizzazz

My view is that electric makes sense for the vast majority of marina bound sailing vessels today but the perception that we have is that we need the range (even though we rarey use it). Long run, I believe that if sailing vessels are engineered around electric (batteries in the keel or bilge), it would make a big difference in viability. Especially if there is a storage repurchase option so that when at the dock you can “lend” your storage to the grid. It will take time though.

Other than propulsion, I think electric is viable today for cooking on board (especially with a smart pressure cooker) and even for the grill. It is also a great solution for dinghies (with a foldable solar panel). It is not that good for heating space or water.

For typical small motor vessels, diesel is by far the best choice today, but for large, displacement cargo ships - I am not so sure. Someone needs to do the math of the energy required to move a cargo ship across the ocean and the different ways to provide this energy (batteries, gas turbines) and I am not sure which way is more efficient. It would not be as clear cut as it is for small vessels though.

SV Pizzazz

actually they are extremely efficient when you figure out the amount of fuel per teu per thousand miles . And at what speed .

https://transportgeography.org/?page_id=5955
which st 21 knots basically means .019 gallon per hour per TEU ( per 40 ft container)

[jmorrison146]

Originally Posted by Sailmonkey

What I see as a looming problem is the current electrical grid.

No-one likes to address this weakpoint. Sections of the US already experience rolling blackouts during times of peak demand.

For the foreseeable future electric cars etc are fine as a novelty, but in order to mainstream them, large changes will need to be made in the power generation and distribution grids globally.

I agree. The US grid, often referred to as the most critical infrastructure in the world, is extensive but brittle. A shift from internal combustion to all electric is a fantasy. Half of the electric vehicles in the US are in Los Angeles and Orange Counties no they're more of a fashion statement than a versatile vehicle. People that own them will fly distances that most others will drive.

The Green New Dream of charging stations everywhere is a fantasy too. We live in a six-unit condo with an underground garage for 14 cars. One owner had a 220V outlet put in the garage for his electric vehicle. The electrician said that and the existing 220V outlets in the six condos is all the building will handle -- the infrastructure from the street will not support any more 220V outlets.

[cj88]

Originally Posted by Pizzazz

My view is that electric makes sense for the vast majority of marina bound sailing vessels today but the perception that we have is that we need the range (even though we rarely use it).

The same goes for cars. There is so much range anxiety but in reality, most trips are actually very short and quite a number could even be replaced by bikes or ebikes. People have an idea of how they might use it e.g. the big cross-country road trip but for most, that reality never eventuates.

In a boat, if you're not needing to cover large distances by motor and don't need to be there by a specific time then electric or a hybrid system may be worth considering when it comes time to repower.