diesel/electric hybrid

[David M]

Originally Posted by Evan

Frankly to me, the current crop of hybrid propulsion systems seem like a solution needing a problem. They won't be more efficient with the mechanical -> electric -> mechanical conversions required; they are a lot more complex and won't be easily repaired outside of first world countries.

If you want to generate power while sailing, I agree that a towed generator (or solar panels) are a much cheaper and more reliable option.

Thanks Evan,
Its nice to hear from an expert who designs propulsion systems for a living and who gives his professional opinion about this technology as applied to yachts. This is compared to so far only having heard from sales people who are pushing this technology, I suspect purely from a sales/profit motive. I don't necessarily mean this forum, I mean everywhere I am reading about "hybrid" propulsion...Lagoons website, etc, none of which mention the downside of diesel-electric "hybrid" boats. It's good to hear from someone who is neutral on the subject and is an expert.

There is so much talk about keeping things simple. Hybrid boats do not seem to be keeping things simple.

David

[Alan Wheeler]

I think if people have the wrong expectations about hybrids then they'll be very disappointed. If they fit your usage profile then they have their attractions.

Well said. I certainly want to see alternative solutions. I certainly like the idea of D/E. And I certainly think that there is a place for it. But one has to understand the positives and negatives of these systems. If they don't understand the negatives, it will become a very big disappointment not too far down the track.

[ess105]

We should also remember there are two similar sounding but very different solutions. There are the diesel electrics and the diesel electric hybrids. The main physical difference between the two is that the latter has the battery banks that allow stored energy to be used for propulsion and house bank cross charging. The Lagoon 420 electrical system is a lot more than an analogue to a towed generator. You have instant power on demand. The system is constantly on and will deliver power (rather than regenerate) if drive from the sails drop. Now I don't want to use this as a crutch but it's nice to know I can't fail a tack and I won't lose power if the sails stall in a more tricky situation.

[Maren]

I understand there is some concern over a new technology. Nigel Calder likes the idea enough to sell his boat and build the same type only with a diesel electric system though.

http://www.capi2.com/downLoads/nigelCalder.pdf

I think I'll see what he thinks after the bugs are shaken out.

[Hampus]

Hey!

I spent 6 years in the swedish navy on diesel electric subs. The swedish subs are, in addition to the diesel engines, all equipped with sterling engines for AIP (Air Independent Propulsion) which makes it possible to charge the batteries even while submerged. There are also Sterling engines on the open market for home and personal use. One is called WhisperGen and pruduces 800W of power and 6kW of heat. Sterling engines are vitually noiceless while running and the combustion is very effective, leaving very little exhaust fumes. This would, I think, be an ideal combination with an electrical engine. Problem seems to be all the extra weight with a generator, electrical engine and a large enough battery bank.

Whisper Tech Limited

Diesel generator 0 1 kva - WhisperGen 12 VOLT DC (silent) - WHISPERGEN - NauticExpo

/Hampus

[gosstyla]

Diesel electric still doesn't seem to scale down very well. For warships and large cruise liners it probably works. However, on small boats if you use less than 40KWH or 50KWH per day for "house" use I think you will have a hard time getting the efficiency from a diesel electric system comparable to a common straight diesel for propulsion plus maybe a small genset for "house".

I recently sailed from Chile, 40* south, through the Panama Canal up to Ft. Lauderdale. My boat had OSSA 2 x 25 KW gensets and 2 X 32 hp electric motors. In addition I lived on the boat in Chile from Sept , 2006 to Sept, 2007 testing the systems.

[henryv]

gosstyla - It's nice to get feedback from someone who has lived with the technology for a while. I am curious to know whether you believe a system incorporating batteries in the equation might be a better way to go. I have had trouble seeing the upside to the straight diesel electric approach but if newer, lighter, high capacity batteries become more affordable it does seem that there should be some merit in the concept.

I am puzzled still by the rational for d/e drive on any monohull sailboat. At cruising speed on a fuel per mile powered basis, it isn't more efficient that a regular diesel. The system is no lighter or easier to maintain. It might let you distribute weight more efficiently, but its a high cost way of doing that.

The situation might switch around a bit on a cat. The need for two propulsion units means I can feed both hull's drive units from a single diesel engine. Maybe producing a simpler installation. Maybe.

A direct drive diesel in a sailboat is actually a very efficient device. If we are using it to motor significant distances, we are running the engine at close to its maximum efficiency point, and if the prop is well matched, everything is humming along with rather small losses.

On the other hand if our design spec is for a motor that will only need to run at full power for very relatively short periods of time, a D/E system will produce at least theoretical savings. We can put in a small diesel, and big batteries. The engine will run for longer periords of time, but the whole system might be great for a daysailor.

The reason hybrid cars work is that at highway speeds power needed is very much lower than during acceleration. The car can cruise on a tiny little engine at 70 mph, and use the energy stored in the batteries to get to that speed in less than a week.

A boat doesn't work like that. Maximum power needed is at maximum speed. There is no point while at cruising speed when power needs are reduced.

Originally Posted by Hampus

Hey!

I spent 6 years in the swedish navy on diesel electric subs. The swedish subs are, in addition to the diesel engines, all equipped with sterling engines for AIP (Air Independent Propulsion) which makes it possible to charge the batteries even while submerged. There are also Sterling engines on the open market for home and personal use. One is called WhisperGen and pruduces 800W of power and 6kW of heat. Sterling engines are vitually noiceless while running and the combustion is very effective, leaving very little exhaust fumes. This would, I think, be an ideal combination with an electrical engine. Problem seems to be all the extra weight with a generator, electrical engine and a large enough battery bank.

Whisper Tech Limited

Diesel generator 0 1 kva - WhisperGen 12 VOLT DC (silent) - WHISPERGEN - NauticExpo

/Hampus

I did some extensive evaluation of the WhisperGen system, and while really neat and a cool piece of technology, it is NOT an efficient generator of electricity. Advertising claims of really high efficiencies include being able to use the excess heat from the combustion. If you are on a boat in the tropics the last thing you need is extra heat!

Look carefully at the specs of fuel used compared to electrical power generated, and compare to a traditional genset. You'll find the internal compustion engines a lot more efficient in generating electricity.

If you are in a colder climate, and need to generate heat, then the WhisperGen sterling engines might have a place. They ARE more efficient than having one system to generate electricity and a seperate system to generate heat.

Bill

[DeepFrz]

Maren, last I read about Nigel Calder's plans are that they are not cast in stone. If there is a case for D/E he will go that way but he is not entirely convinced and is waiting to see what the near future brings. At least that is the way I interpreted his writing.

August/Sept 2007 Professional Boatbuilder
Professional BoatBuilder - August/September 2007

[Maren]

Originally Posted by DeepFrz

Maren, last I read about Nigel Calder's plans are that they are not cast in stone. If there is a case for D/E he will go that way but he is not entirely convinced and is waiting to see what the near future brings. At least that is the way I interpreted his writing.

August/Sept 2007 Professional Boatbuilder
Professional BoatBuilder - August/September 2007

I dunno, I think the first and second paragraphs stated it pretty clearly.

He sold his nearly new Malo 46 so he could "rebuild the same boat again with a new -- that is, advanced -- electrical system."

However, he does point out (in I think one of the three articles he references in this one) that in the event the technology doesn't work out he, unlike most of us, could recoup part of the costs by writing about the problems with system.

An enviable position. I however, will watch and wait.

It is also worth pointing out this sort of technology has been used other industries for 30 or so years. If it scales down or not, is left to be seen.
Personally, even with the pounds dropped from wiring, a smaller generator, etc, I don't think there will be much (if any) weight savings. But I do think we will see a increase in range due to fuel efficiency. Someone told me a while back about a side by side comparison with two Outremers and, if I recall, that was the conclusion too. But I haven't read it and I don't know anyone who was there.

[DeepFrz]

Maren, which reference are you referring to, the 2005 article that you link to or the 2007 article that I link to?

[Maren]

Originally Posted by DeepFrz

Maren, which reference are you referring to, the 2005 article that you link to or the 2007 article that I link to?

The quote was from the article you linked to. The reference was to one of the three articles he references in the 2007 article. I think issues 96, 97 & 98, but I don't recall off hand and I'm getting ready to head off. I don't rule out that I may be wrong because I had a decent amount of time today and I read five web articles by NC, most on the same topics. I'm happy to look it as I'll end up re-reading and I find I usually pick up some new connection I had missed. And I like his style as its fairly straight forward.

I'd like a system like this work, but that doesn't mean it will. Even with lots of engineers and well-respected authorities optimistic. One cited industry is the automotive but we all know there are significant differences in the batteries which seem to preclude an exact comparison. Calder addresses the issues of charging and battery technology in others but this still strikes me as a having great potential. But only time will tell if is it realized.

[gosstyla]

henryv,

I assume you mean batteries for propulsion. Originally I looked at the Solomon Tech system but quickly saw batteries plus "prop regeneration" would not meet my requirements. For someone only needing power to get in and out of a harbor it might work but for long term, world cruising I believe something that can be counted on is needed to produce the electricity - genset, fuel cells, etc.

[DeepFrz]

The diesel/electric technology may be getting close to being ready but according to Calder it's not there yet, especially for the smaller cruiser. In the mean time the new diesels are getting much more fuel efficient, lighter and quieter making it more difficult to overcome even reduced conversion costs.