An interesting development

[Capt Ray]

https://www.powerandmotoryacht.com/boats/sea-trial-and-review-of-the-silent-55-solar-electric-power-catamaran

This one makes more sense to me.

 

[twistedtree]

We are the North American distributors for the Steeler 61S Electric and have promoted her at the last three TrawlerFests and other events. She was designed by our partners at Vripack to meet the specific needs of her live aboard Norwegian owner. We would be happy to discuss her pros and cons as we see them. Perhaps a better solution is the hybrid propulsion system that we will be installed in the Doggersbank 77 we are starting to build in March. The Steeler 61S
Electric is an innovative boat and could be also built with hybrid propulsion.

Perhaps you could sketch out some of the specifics of the electric power system? Battery capacity? Cruise speed and motor power for the 4 hrs run, 2hr recharge+run, 4 hrs run? As noted by others, this cruise patterns lasts you at the dock with dead batteries. What shore power provisions are expected, and what is the recharge time?

 

[klee wyck]

Perhaps you could sketch out some of the specifics of the electric power system? Battery capacity? Cruise speed and motor power for the 4 hrs run, 2hr recharge+run, 4 hrs run? As noted by others, this cruise patterns lasts you at the dock with dead batteries. What shore power provisions are expected, and what is the recharge time?

AAARGH….
This 4-2-4 thing is killing me here!
The theory here is during the two hours you are going to use a Diesel engine to deliver enough power to an electric motor to propel the boat for those two hours and also make and store enough power to run the boat another four hours.
Summary: in two hours your are going to produce enough power to run the boat for 6 hours with only 1/3 of it being used to propel the boat….
Newsflash: if applied all of that power coupled directly to the shaft and you had the correct hull form, you would be at your destination at the end of those two hours and would have four spare hours for cocktails.
However, You may have had plenty of cocktails already if you are biting on this pitch.

 

[Northern Spy]

Many of the Europeans builders already say all their models are available as diesel/electric hybrids. They claims fuel savings of between 25-35 %.
When configured as serial hybrids, there is no power loss in transmissions, since they are direct drive. Then too , as other have mentioned, you use a slaller genset, and it will always run at its 'sweet spot'.

They let me post, but not reply now. Thats what this group is like.
https://www.volvopenta.com/about-us...el-hybrid-marine-propulsion-how-do-they-work/
Parallel has propulsion diesels, in series, just gensets.
A few of us here have been posting abou boat electrification for years already, and cited many example, including a hybrid 22m longliner, just a few days ago.
Another reason the euopeans are advanced in this field is because its not just for fuel savings, but also for pollution abatement. In harbors they dont pollute at all..

You have serial and parallel reversed. Parallel hybrids have mechanically connected diesels, serial hybrids do not.

 

[Northern Spy]

When you really get down to it, Having a clutch and a MG set in line between a Diesel and a propeller is not new technology. It's existing tech put into a dubious new application.

 

[sunchaser]

When you really get down to it, Having a clutch and a MG set in line between a Diesel and a propeller is not new technology. It's existing tech put into a dubious new application.

Here's a question for a submariner- if not for nuclear power, what new battery and diesel systems would be in use today given current technology? Would today's tech be reflected by faster submerged speed, greater range or greater reliability?

 

[Mambo42]

https://www.powerandmotoryacht.com/...-the-silent-55-solar-electric-power-catamaran

This one makes more sense to me.

Tristan Mortlock, on Youtube known as Superyacht Captain has done a 4 episode report on this boat. Quite interesting.

 

[Art]

Every Minute is Super Informative!

How a Diesel-Electric Locomotive Works

 

[twistedtree]

Here's a question for a submariner- if not for nuclear power, what new battery and diesel systems would be in use today given current technology? Would today's tech be reflected by faster submerged speed, greater range or greater reliability?

Interesting question. Really the big difference is that today's batteries pack more power into a smaller space, so a sub could carry more energy in the same space. They are also more efficient. All that translates into some combination of increased submerged speed and range.


Also, today's batteries might be rechargeable faster which means less surface time running diesels before you can once again submerge. I say "might" because I think it depends on whether old subs charged through absorption, which takes a lot of time, or if they just bulk charged and dove. Maybe it was a bit of both? Any old submariners were?

 

[JWellington]

Northern spy......thats just what I said. In parallel, the diesel motor is directly turning the prop......but in serial, the genset just produces electricity that goes either doerctly to the electric motor, or to the batteries. Thus in serial, no need for a transmission, thus more power saved. Plus the genset is always at its sweet spot.

 

[JWellington]

In hybrids its normal to see warranties of 8 years on batteries, 25 years for the solar panels, lifetime for the electric motors.

 

[sunchaser]

In hybrids its normal to see warranties of 8 years on batteries, 25 years for the solar panels, lifetime for the electric motors.

Solar panels at 25 years is all too often a sales gimmick if there is not a contractual performance statement attached. Our direct dirt home neighbor had a large solar array installed 8 years ago.

After 10 years the power company and Tesla/ Solar City agreed that power output had decreased below the stated design range. 20 new 3x6 Canadian Solar panels were just installed at o cost.

Thumbs up for a 25 year performance and maintenance agreement from an established company. If one's marine solar array drops below agreed ranges best to be close to that specific vendor.

 

[twistedtree]

Northern spy......thats just what I said. In parallel, the diesel motor is directly turning the prop......but in serial, the genset just produces electricity that goes either doerctly to the electric motor, or to the batteries. Thus in serial, no need for a transmission, thus more power saved. Plus the genset is always at its sweet spot.

But that ignores the introduced losses in generating power in the generator, storing and retrieving it in/from a battery, and losses in the drive electronics and motor. None of that exists in a direct diesel to prop drive, so all losses introduced in a serial hybrid. A drive engine can be sized for sweet spot operation just as a generator can be sized.


A serial hybrid is a total fail from an energy efficiency perspective unless there is a significant energy recovery potential as found in a car or even a locomotive via regenerative braking. In other applications, the reduced energy efficiency is accepted in exchange for other benefits like maneuverability (self-docking cruise ships, tractor tugs, etc.), or traction power transmission characteristics like in a locomotive, or even just quiet propulsion for the joy of it.



But we have run around this tree before, over and over again. Wanting to believe it's efficient doesn't make it so. And vendors building boats for people who want to believe doesn't make it so either.

 

[twistedtree]

AAARGH….
This 4-2-4 thing is killing me here!..... However, You may have had plenty of cocktails already if you are biting on this pitch.

But just think about the conversations you will have with your guests over those drinks, aboard your ever-so-advanced hybrid boat that demonstrates your commitment to the planet and sustainable living. You are DEFINITELY getting laid tonight, and that's why you bought the boat...

 

[mvweebles]

......
But we have run around this tree before, over and over again. Wanting to believe it's efficient doesn't make it so. And vendors building boats for people who want to believe doesn't make it so either.

This guy really is catnip to some of us, huh? He's never owned a boat, never will - God forbid if he ever made it onto a waterway. Yet his troll posts are irresistible just like when you discover a long expired carton of milk in the back of the fridge: just gotta sniff it even though you know whats coming.

Peter

 

[twistedtree]

In hybrids its normal to see warranties of 8 years on batteries, 25 years for the solar panels, lifetime for the electric motors.

That's great, but doesn't address the efficiency question. Or are you saying that reduced efficiency is worth it because you get a longer warranty on some parts?

 

[Porgy]

Sounds good to me. Doesn’t have enough power to get out of its own way and can only get as far as the end of the dock. But what a great warranty!

What’s curious about fairytale warranties is that in 8 or 25 years, assuming the company is still in business, the technology will have advanced well beyond what I bought. It’s quite possible the warranty would only cover like for like and I’d have to pony up anyway to get a replacement for my obsolete broken doodads.

 

[mvweebles]

The warranty on most solar panels is that they will achieve 80% of their rated output after 20-years. Outside of impact damage they are pretty reliable but do see a 2%-3% decline each year. Its also hard to meaaure the actual output so making good on a warranty is iffy. And they are getting cheaper and more efficient - warranty really isn't practical beyond install issues.

The Achilles Heel are controllers which carry minimal/no warranty.

Peter

 

[JWellington]

We are the North American distributors for the Steeler 61S Electric and have promoted her at the last three TrawlerFests and other events. She was designed by our partners at Vripack to meet the specific needs of her live aboard Norwegian owner. We would be happy to discuss her pros and cons as we see them. Perhaps a better solution is the hybrid propulsion system that we will be installed in the Doggersbank 77 we are starting to build in March. The Steeler 61S
Electric is an innovative boat and could be also built with hybrid propulsion.

What do you say to those here who dont accept byilders warranties? Several have expressed that when I mentioned common warranties..

 

[twistedtree]

https://www.powerandmotoryacht.com/...-the-silent-55-solar-electric-power-catamaran

This one makes more sense to me.

Looks like the same boat that Tristan reviewed on YouTube. A super light weight carbon fiber catamaran makes sense for getting the most from hybrid propulsion, in the same way it makes sense for getting the most from wind propulsion.


Let's look at the numbers for this boat. Note that the magazine article has a number of inconsistencies like a 10,000 kw solar array, so typical trash reporting, but I think we can make sense of it...


They say it can do 5-6 kts on solar along. I'll assume that's optimistic, as all such claims are, so assume 5 kts on the 10kw solar array. That's about a 13hp propulsion motor, so seems believable.


The battery bank is 210kwh, and since we can't use 100% of it's capacity, let's round that to 200kwh. That will run the boat at 5 kts for 20hrs which is pretty good, and matches reasonably with the solar power available during the day. Full solar power is typically available for 5-6hrs per day, assuming clear, sunny weather.


So if you are running 24x7 you would get 5-6 hrs on solar, and the remainder on batteries. Then you would need to run the generator to recharge. Assuming there is 100kw of battery charging capacity to match the 100kw generator output, recharging the batteries will take 2 hrs. However most generator manufacturers won't allow 100% load with non-linear loads like battery chargers. Plus, does this boat really have 100kw of charging capacity? Maybe, but wow, that's a lot. So maybe it takes 2.5 to 3 hrs to recharge?


All in all it's not bad, but keep in mind that you are only moving 5 kts, and that's mighty slow for a 55' catamaran.


Let's look at energy efficiency. This is apparently a serial hybrid, so all propulsion comes from electric, either drawn from batteries or from solar. Looking at the solar vs battery duty cycle above, we have about 20-25% of the power from renewable solar, and 75-80% from diesel generated and stored electric. With a conventional direct diesel drive, about 97% of the diesel output is converted into propeller drive power. With a diesel electric, it's around 75% (very best case). So if we ran this boat completely off hybrid we would see a 25% increase in fuel consumption. But since we can also run off the solar, we can recoup that 20-25% of lost efficiency using solar. That means that this boat is about break even compared to a conventional drive. That's running at 5 kts. At any higher speed, it will go negative again since total power requirements will go up, yet the solar contribution will remain fixed so be a smaller portion of the overall power demand.


If you are just puttering around, it should do better. Also note that at full speed which was reported to be about 14 kts, the batteries will only last 20 minutes or so.


This boat may get you laid, but it's unlikely to get better fuel economy than a conventional drive, and of course is a much more complicated system.

 

[backinblue]

T-Tree, I agree with your comments and was thinking the same. If they say 5-6 knts, I'd assume 5 is more likely, and on a 55' cat, that would seem very slow. Also, that probably is in relatively ideal conditions. What happens when you are fighting wind and waves and currents or the sky is less than fully clear or the sun is lower in the sky due to time of day or time of year. Even with all that solar, it still barely seems to be viable in any real way.

 

[JWellington]

Regarding the gensets on the seies hybrid boats. Some people are concernedd that they are satisfactory for intended use. The builders of all those various hybrid boats insist they are, like: Steeler, Damen, Silent Yachts, Alva Yachts, Wirtsala, Moen Marin, Herley, Zen Yachts. Thats just a short list, but sure, they could all be lying and didnt bother to factor in appropriate gensets.

 

[twistedtree]

Regarding the gensets on the seies hybrid boats. Some people are concernedd that they are satisfactory for intended use. The builders of all those various hybrid boats insist they are, like: Steeler, Damen, Silent Yachts, Alva Yachts, Wirtsala, Moen Marin, Herley, Zen Yachts. Thats just a short list, but sure, they could all be lying and didnt bother to factor in appropriate gensets.

Are you referring to this from my post #113?

Assuming there is 100kw of battery charging capacity to match the 100kw generator output, recharging the batteries will take 2 hrs. However most generator manufacturers won't allow 100% load with non-linear loads like battery chargers.

If so, you misunderstand what I'm saying. I didn't say anything about suitability of the genset for intended use, just that genset manufacturers typically limit linear loads to a portion of rated output. The specs for the boat under discussion don't specify the battery charging capacity, so I made an estimate based on typical de-rating, as I would expect reputable builders to de-rate their designs.


If you have more concrete info about the boat, it would be welcome. As would any knowledge about generator rated capacity vs charger loading by all the builders you mention. Just a list of names of companies building boats doesn't provide any insight into how this boat is built, or how it will perform.

 

[mvweebles]

For future reference, if you want to flag a post for inappropriate content, best way is on a PC. There is an icon that fast-tracks to the moderators for a determination.

Peter

 

[mvweebles]

..... As would any knowledge about generator rated capacity vs charger loading by all the builders you mention. Just a list of names of companies building boats doesn't provide any insight into how this boat is built, or how it will perform.

I wish these threads about leading-edge appplications of technology would dig into the fundamentals. Up-thread (#90) "JOHN CLAYMAN" states he is part of the North America distributorship for Steeler Yachts with options for hybrid propulsion. The naysayers would probably outnumber the truly interested, but let's be honest - pure hydrocarbon based propulsion will decline; and alternative sources will ascend in the future. Solar? Hydrogen? Who knows - but it has started and will eventually gain a toe-hold in the market. I would welcome the opportunity to sit in the bleachers and see the give/take technical discussion about current 'art of the possible' and the inherrent flaws ---- then watch as gaps are closed.

Peter

 

[mvweebles]

Regarding the gensets on the seies hybrid boats. Some people are concernedd that they are satisfactory for intended use. The builders of all those various hybrid boats insist they are, like: Steeler, Damen, Silent Yachts, Alva Yachts, Wirtsala, Moen Marin, Herley, Zen Yachts. Thats just a short list, but sure, they could all be lying and didnt bother to factor in appropriate gensets.

These are multi-million dollar boats. Asking the builder to 'show their homework' is not unreasonable - it has to be fit-for-purpose. While I'm no expert here, sounds like you've been confused by marketing claims about whether something is hybrid or not; and configuration of hybrid systems (series/parallel which are new terms for me in this space). If I were in your shoes, instead of defending "clever" builders' statements, I would eagerly devour the input from folks like Sunchaser, TwistedTree, and others on this forum who have come up with some very good questions to ask. But that would assume I was a buyer, not a bystander.

There is another active thread where someone's newly constructed boat is just being completed and the builder seeks to prohibit the buyer/owner from verifying promised construction details. And that's presumably on established technology. That builder is likely offended that someone wouldn't just take their word for completion.

This is new application of technology. Designers and builders should welcome the proctological examination that will ensue. But hey, if there are enough customers who, like yourself, are willing to take their word for it, I suppose they won't bother.

Peter

 

[JWellington]

Are you referring to this from my post #113?





If so, you misunderstand what I'm saying. I didn't say anything about suitability of the genset for intended use, just that genset manufacturers typically limit linear loads to a portion of rated output. The specs for the boat under discussion don't specify the battery charging capacity, so I made an estimate based on typical de-rating, as I would expect reputable builders to de-rate their designs.


If you have more concrete info about the boat, it would be welcome. As would any knowledge about generator rated capacity vs charger loading by all the builders you mention. Just a list of names of companies building boats doesn't provide any insight into how this boat is built, or how it will perform.

IF a genset limits, THEN its not appropriate. Its possible all those hybrid boat builders never thought of that.....but I dought it. What a potential buyer can do is make explicit inqiries about the rating of the genset. They could also find out what the specific make it is, and check the duty ratings, etc with their makers whether CAT, or Volvo, etc. My bet is that they will have put in gensets that can operate for more than 2 hours.

 

[JWellington]

These are multi-million dollar boats. Asking the builder to 'show their homework' is not unreasonable - it has to be fit-for-purpose. While I'm no expert here, sounds like you've been confused by marketing claims about whether something is hybrid or not; and configuration of hybrid systems (series/parallel which are new terms for me in this space). If I were in your shoes, instead of defending "clever" builders' statements, I would eagerly devour the input from folks like Sunchaser, TwistedTree, and others on this forum who have come up with some very good questions to ask. But that would assume I was a buyer, not a bystander.

There is another active thread where someone's newly constructed boat is just being completed and the builder seeks to prohibit the buyer/owner from verifying promised construction details. And that's presumably on established technology. That builder is likely offended that someone wouldn't just take their word for completion.

This is new application of technology. Designers and builders should welcome the proctological examination that will ensue. But hey, if there are enough customers who, like yourself, are willing to take their word for it, I suppose they won't bother.

Peter

You said serial vs parallel propulsion are new terms for you, but theyre not for me. (as I recently pointed out to you that serial hybrids dont need a transmission). No builder selling multimillion dollar boats can be offended by asking specific questions like what sort of gensets the use, etc. Except for Moen Marin, a Norwegion builder, I have asked very specific details, even thickness of windows, how think, if heated , bolted or glued on, specific company that supplies them, etc. All sorts of stuff, and they usually have the info at hand, and like selling boats. They all have many competitors. Lots of guys buy multimillion dollar boats.

 

[mvweebles]

You said serial vs parallel propulsion are new terms for you, but theyre not for me. (as I recently pointed out to you that serial hybrids dont need a transmission). No builder selling multimillion dollar boats can be offended by asking specific questions like what sort of gensets the use, etc. Except for Moen Marin, a Norwegion builder, I have asked very specific details, even thickness of windows, how think, if heated , bolted or glued on, specific company that supplies them, etc. All sorts of stuff, and they usually have the info at hand, and like selling boats. They all have many competitors. Lots of guys buy multimillion dollar boats.

You asked window thickness but take their word on propulsion specifics?

At any rate, sounds like you have all the answers you need. Not sure how TF can assist you.

Good luck. Will anxiously await which "clever" Dutch or Norwegian design you purchase.

Peter

 

[Steve DAntonio]

An interesting article, printed in a major marine pub, that refreshingly explores the challenges of electric propulsion. I have known the author, he is savvy and was perhaps the first journalist to pass the ABYC Electrical exam.

This is a complex subject with few one word answers, and it is evolving. Regardless of efficiency claims, I once again remain concerned for reliability and serviceability of these systems. Anyone considering such a purchase must ask those questions of the seller/builder and carefully and critically scrutinize the responses.

https://www.cruisingworld.com/story/sailboats/the-promises-and-pitfalls-of-an-all-electric-yacht/