An interesting development

[Mr. Blu]

Steeler Yachts in the Netherlands has come up with a full electric ocean going trawler. The 61 S Electric.

An interesting (but also not cheap solution) development.

See the 61 S Electric. Www.steeleryachts.com

Paul

[mvweebles]

Good looking boat. And an interesting concept. Here is some design parameters from the builder.

The battery sets comprise 18 containers, each with 16 cells, sufficient for an action radius of 4 hours’ sailing. Out on the ocean waves, a diesel generator provides the power. The batteries are charged in two hours, so that the generator only needs to work two hours during a full 10-hour sailing day.

I don't quite follow the math, but do get the concept. Getting much closer to reality......

Peter

[KnotYet]

Their brief description states that a generator powering an electromotor is more
efficient than a direct diesel engine propulsion so already off on the wrong foot...

Still, that boat's power system design is going where few others are daring as yet.

[RT Firefly]

Greetings,
How much longer will one have to operate the generator as the batteries deteriorate and what is the cost to replace the batteries? There's no free ride.

[garbler]

Originally Posted by KnotYet

Their brief description states that a generator powering an electromotor is more
efficient than a direct diesel engine propulsion so already off on the wrong foot...

Still, that boat's power system design is going where few others are daring as yet.

Not sure I understand your statement. Are you saying a straight coupled diesel drivetrain is more efficient than a diesel electric drive ? Heh just asking cause I’m figuring you know something that I may need to know

Rick

[garbler]

I’ll bet they run with a diesel fired heating system though.

Rick

[PierreR]

I would love to see that math on being more efficient. I does not add up for me unless you are counting the solar panels as part of the diesel electric propulsion. Even then it probably takes plugging into the grid to make the numbers work.
Lithium Ion? I would not touch it unless it was Lithium Ferro phosphate. Maybe there is something new I am unaware of.

[twistedtree]

Originally Posted by garbler

Not sure I understand your statement. Are you saying a straight coupled diesel drivetrain is more efficient than a diesel electric drive ? Heh just asking cause I’m figuring you know something that I may need to know

Rick

Yes, I think that is precisely what he's saying. Or if he's not saying it, I will.


You can't take an engine and a propeller (conventional drive) and insert a generator, batteries, and a motor in between the two and not lose power.


This is science for people who skipped or failed high school physics

[garbler]

I’m incapable of running the math but can tell you that the USN had diesel electric propulsion drivetrains not unlike the railroads that out performed straight engine thru reduction gears to shafts set ups. The big problem was cost, which the navy never factors, and weight as the generators and drive motors were large to say the least. But these diesel electric tugs put full horsepower to the screws instantaneously unlike their counterparts and out performed all others. So yes probably sucking up some HP in favor of performance.

Rick

[KnotYet]

Originally Posted by garbler

I’m incapable of running the math but can tell you that the USN had diesel electric propulsion drivetrains not unlike the railroads that out performed straight engine thru reduction gears to shafts set ups. The big problem was cost, which the navy never factors, and weight as the generators and drive motors were large to say the least. But these diesel electric tugs put full horsepower to the screws instantaneously unlike their counterparts and out performed all others. So yes probably sucking up some HP in favor of performance.

Rick

You are not considering the efficiency loss that is unavoidable when converting
one form of energy to another. Generating the power then converting it back into
rotation will easily cost 30-40%, much of that in waste heat. Boats have been
built with multiple generators that can be brought on-line as needed, thus
regaining some efficiency at the cost of weight, complexity and, well, expense.

A tug, like a locomotive, is an ideal use case for diesel electric drive. The ability to
have maximum torque at low RPM is what electric motors do best and makes
sense for those conditions.

[sean9c]

It'd be interesting to know what the speed is under battery power when attempting to get the 4 hour usage.

[klee wyck]

Originally Posted by twistedtree

Yes, I think that is precisely what he's saying. Or if he's not saying it, I will.


You can't take an engine and a propeller (conventional drive) and insert a generator, batteries, and a motor in between the two and not lose power.


This is science for people who skipped or failed high school physics

This^^

The laws of thermodynamics are non-negotiable. Any time energy changes state, some is lost as heat/entropy.
This whole hybrid electric thing has baffled me unless the source of the electricity is PV and that is a very limited source when it comes to moving large objects over long distances.

Still a skeptic on this, though I am a huge fan of science and technology and expect someday there will be a breakthrough. That breakthrough will not involve burning diesel to make electricity.

[AlaskaProf]

Originally Posted by garbler

I’ll bet they run with a diesel fired heating system though.

Rick

One would hope. Heat or AC kill 20+% of the range on my electric cars. Surely an even bigger cost at 8 knots.

[mvweebles]

WSJ just had an article that EV sales in Europe are slumping, partially due to increase cost of electricity courtesy of Russia's invasion of Ukraine. Apparently, cost of gas and diesel made EV power particularly attractive. Probably no coincidence that the leading edge of larger power yacht electric boats is coming out of Europe (with possible exception of Greenline, though those are smaller).

Consider a typical use case where a boat gets used as a day-trip platform where you take some friends out, perhaps to a nearby destination, and return. For many, that covers 80% of their usage. This boat is designed to do that under electric power only. Range anxiety is removed with generator/electric power as backup, or of course that can easily extend the range. Not unlike the burgeoning crop of plug in hybrids.

Personally, I find this type of boat interesting and exciting. Sure there are issues to solve, but I hope it's the beginning of a trend, not a stepping stone of a fad.

Peter

[Barking Sands]

Originally Posted by KnotYet

Their brief description states that a generator powering an electromotor is more
efficient than a direct diesel engine propulsion so already off on the wrong foot...

Still, that boat's power system design is going where few others are daring as yet.

I think their statement is lacking in details. But in a properly designed diesel electric system, especially with newer battery technology, can probably come close to breaking even and in some cases exceed certain examples.

Having the ability to run a particular engine at a specific RPM allows you to target the most efficient operating range. BSFC of existing engines varies greatly from idle to redline. When an engine has to operate across an rpm range it suffers in efficiency. Especially when including idling out of gear, which boat diesels have to do frequently.

So If you take a Cummins 6BTA that has to use an operating range from idle-out of gear all the way to max operating RPM to propel a vessel and compare it to the same Cummins 6BTA that will spin a generator at peak BSFC you are already gaining a tremendous amount of efficiency back.

But that is not where the huge gains can be had. The 6BTA above was designed to operate smoothly over a broad range of RPM and the engineers had to make many compromises to achieve that. Camshaft design specifics , valve size, port size, exhaust design, compression ratio, cooling capacity, and on and on was all a compromise in order to operate over a wide range of rpm.

Designing an engine with a very narrow range of operating RPM to specifically drive a matched generator can greatly increase average BSFC. In addition there are no idle times that result in 0 useful output since no propulsion operating time is charging large batteries.

Also factor transmission losses in a traditional configuration VS some direct drive electric systems.

I still doubt their claim is true but I have no doubt you could design a diesel electric/battery propulsion system that IS in fact more efficient than many old mechanical diesel. So I doubt its as simple as some might think. Both sides of the balance sheet need to be added.

[Comodave]

Originally Posted by garbler

I’m incapable of running the math but can tell you that the USN had diesel electric propulsion drivetrains not unlike the railroads that out performed straight engine thru reduction gears to shafts set ups. The big problem was cost, which the navy never factors, and weight as the generators and drive motors were large to say the least. But these diesel electric tugs put full horsepower to the screws instantaneously unlike their counterparts and out performed all others. So yes probably sucking up some HP in favor of performance.

Rick

Performance isn’t the issue, electric motors develop torque almost instantly. Efficiency is the question. Tell me when the Navy ever cared about efficiency? They really don’t care about fuel consumption.

[PierreR]

Barking Sands, there are just too many loss areas that don't ad up even if things are designed perfect.
You have generation losses similar to a transmission, then since you generate in AC, you run a charger to charge the batteries. The best chargers lose close to 10%. Then you have chemical conversion losses in the battery both charging and discharging. Then you have losses converting DC battery power to three phase AC power to run the motor and finally, you have motor loses. All those loses add up to far less efficiency than a conventional diesel/transmission setup and end of story, as the article is stated, the wording is wrong. Now do we trust the article author to have gotten it right? All reporters are correct on everything, just ask them. There is not doubt more to the story.
So where do they get this greater efficiency? Quite possibly they are pulling it from typical use patterns and overall diesel usage vs conventional diesel usage. If you run that boat 4 hours round trip to the local restaurant and back and then plug into shore power, you will have very much achieved greater efficiency (pocket book and diesel fuel) than a straight diesel setup. That would cover 90% of how people would use a boat like this. If this is what they really meant, then I concede.
That aside, there are some very interesting doors that would be opened with this type of setup and this type of setup is by all means within reach of many through a refit without the up front costs of a new boat.
One possibility is because of the narrow rpm range you might be able to convert something slow turning to burn light bunker oil if its available. You would also not be restricted to conventional propellers due to the torque curves on electric motors. You could select a propeller to match the characteristics of the electric motor including automatic variable pitch. You can change the characteristic of the torque and power curves by matching different motor controllers.
Wish I was younger, with the likes of HGR surplus sitting out there with cheap cool stuff, it would be fun to play around and experiment making aquatic toys.

[Art]

Originally Posted by mvweebles

Consider a typical use case where a boat gets used as a day-trip platform where you take some friends out, perhaps to a nearby destination, and return. For many, that covers 80% of their usage. This boat is designed to do that under electric power only. Range anxiety is removed with generator/electric power as backup, or of course that can easily extend the range. Not unlike the burgeoning crop of plug in hybrids.

Personally, I find this type of boat interesting and exciting. Sure there are issues to solve, but I hope it's the beginning of a trend, not a stepping stone of a fad.

Peter

Peter - You are spot on... regarding the general use of boats! And, electric propulsion will get better for range as well as inexpensive PV charging... etc.

Back in the day [1950's. 60s, 70s] my family generally cruised only 15 to 25 miles out and same distance back nearly every weekend. Heading out on Thursday or Friday eve we'd anchor in a bay and play all weekend. Cruising back in on Sunday eve. An electric boat that charged from PV during the week would have worked well. Of course - in the 50's diesel was $0.19 to $0.25 cents per gal... so no real big deal for Dad! Now of course it's a different story!

Summers we'd cruise, stopping in harbors, along the New England coast for two to four weeks. Sometimes doing 1000 +/- miles. For that jaunt, to keep moving through the water at speed, today's electric boats would probably need to use a bit of gen power to keep batts charged. - Art

[Bmarler]

Originally Posted by mvweebles

Good looking boat. And an interesting concept. Here is some design parameters from the builder.

The battery sets comprise 18 containers, each with 16 cells, sufficient for an action radius of 4 hours’ sailing. Out on the ocean waves, a diesel generator provides the power. The batteries are charged in two hours, so that the generator only needs to work two hours during a full 10-hour sailing day.

I don't quite follow the math, but do get the concept. Getting much closer to reality......

Peter

You get ten hours as the generator is able to charge and power at the same time. Presuming you left the dock on a full charge.
I like it ok, but it’s definitely not for everyone. I like a more traditional interior with warm wood finishes.

[mvweebles]

Originally Posted by Bmarler

You get ten hours as the generator is able to charge and power at the same time. Presuming you left the dock on a full charge.

I like it ok, but it’s definitely not for everyone. I like a more traditional interior with warm wood finishes.

Got it. That makes sense.

While I totally get the argument that diesel-electric may not be as efficient as straight diesel, it's hard to ignore that running a diesel generator only 20% of the time could be very economical and efficient. Assumes cost of electricity is lower than equivalent diesel and that adequate charging is available at end of 10-hour day.

Everything has its sweet spot for use case. Hybrid vehicles really shine in stop and go traffic where braking regenerates batteries. Not so much on long distance drives. Likewise, this vessel excels in day-hop trips. Assuming adequate fuel stores, it could cross an ocean I suppose but that's not its sweet spot.

Sooner or later, one of these hybrid/electric style yachts is going to push into the early adopter phase. I look forward to it with keen interest. Not for me either, but I applaud the ingenuity and adaptation to environmental constraints.

Peter