The perfect Passagemaker III, propulsion

But not the propeller load problem..

The CPP indeed does solve the problem of making ONE , probably the bigger propulsion engine just right for most conditions.

I wonder if the match up was say, 250hp cont for the larger engine , and 60hp for the genset/cruising LRC engine weather a big perhaps 40 inch prop would work to spin that diameter with most of the pitch cranked out.

It would add complexity if another 2-1? reduction gear was required for the 60 hp to spin a larger prop. And the ability to operate with both engines might be compromize.

With the new lightweight car transplants ,Volvo, Yanmar BMW , it might be OK to have the big engine at 1800 and the smaller at 3600, it would be interesting. At least the car transplant should meet Tier III or whatever the air police decide on next.

FF

 

With diesels the biggest problems in this regard lie in the purity (or impurity) of the fuel and filtering the microparticles away of the exhaust, not so much to do with the engines itself as long as they are working normally..

 

The bigger engine is right for ALL conditions.

I don´t understand why one would really want such a two engine installation? It is at least additional expense and complexity.
For what? You don´t need to run a genny when the main is running. And you don´t need more than about 4kVA DC or 6kVA AC gen. if not. (for a short time only)

 

That might be my question as well...but here is excerpt from their spec sheet:
"Green environmentally friendly engines
The Grenaa Diesel engines fulfill the strict emission limits set by IMO. The outlet of Nitrogen Oxides and Hydro-carbons are well below the permitted values. In some countries this is rewarded by the right to buy fuel excl. pollution related taxes."

 

These big boys have it much easier to fulfil IMO regs than the smaller engines. The thermal efficiency is much better in general, when you go for higher swept cyl. volume. That makes it a matter of finetuning instead of adding additional systems and complexity.

 

For offroad diesels, Tier 4 in the US and 3b in Europe ( applicable this year), will require post combustion cleaning of the exhaust so the engines are going to get complicated no matter what. Note, offroad engines over 560kw are not covered by the above rule
The larger engines have been granted excemptions as the manufacturers have been having trouble getting them to pass.
The classification societys have been able to get IMO exceptions to use them in vessels in the US and European waters so hence you could say yes 'our engines meet the required standard'. that is true.
Note IMO tier 2 is not US EPA tier 2. The IMO regs are also engine speed related so slower engines get more leeway


Particle pollution from large engines is worse then small engines, it was just not one of the first things tackled by the clean air regimes.
High pressure Common rail injection systems ( which need a computer to fire the injectors)which were introduced to get massively high injection pressures to help this are not cheap or simple and the larger you get i.e to fuel a large cylinder with a single injector, the larger the effort.

Saying that the largest engines in the world are computer run common rail. I guess they were the dirtiest, however their thermal efficiancy is very high compared to the rest. They also use the dirtiest fuel of all hence half the problem. They also cost millions and not many are made per year.
There is also the argument like jet passenger planes moving people that per ton of freight they beat everything by miles.

Thermal efficiency although good for miles per gallon does not neccassarliy mean clean emissions. F1 engines are the most thermally efficient Si engines.
Some one like Cummins for example that sells over 40,000 a year of one model engine (ISX15) can afford as they have just done to meet Tier 4, design a new engine from the ground up the ISX 11.9. I dont see the low volume sellers doing this.

As much as I like medium speed engines for all the reasons that we all love them I dont think they can last and we have seen many disappear lately.

(Sorry for the hijack)
So quick get your order in today with Richard while stock lasts!

 

It also helps that at lower RPM and piston speeds, you don't have to use all sorts of aerodynamic trickery and precision computer-timed injectors to accelerate the combustion process, as is the case in smaller high-revving engines. Slow things down a bit and you have the opportunity for much finer control over exactly what is going on inside the combustion chamber.
And yes, as far as I know, ships don't have to worry quite as much about a few of the smog-forming emissions as cars and trucks do. It's not a "spew out whatever you like" and there are still fairly strict limits for boats, but cars are expected to operate in hordes of a hundred thousand at a time in hot, dense regions, and it makes sense that they'd be subject to more restrictive criteria for smog-forming emissions.
They may look like dinosaurs, but modern large, low to medium RPM diesels are among the most efficient ways we have of turning fuel into motion. Yes, there are combined-cycle turbine systems that get ten, even twenty percentage points higher efficiency (GE has one that'll go north of 60% when fully tuned and tweaked), but at the cost of enormous mechanical complexity and bulk.

 

I would have missed something if you would not have contradicted. And you are wrong again!
There is absolutely no need for electronic engine management!

It is not true that these mid speed engines have got any exceptions! The regulations just apply different to engine displacement.

A exhaust treatment system would not effect the propulsion in case of failure, so any further development in that direction does not harm us.
Neither does a fuel/water emulsion to reduce NOx emissions. Just a different set of injectors would be required.

DOC/SCR- Installations are available and within a reasonable price range.
(diesel oxidation catalyst combined with selective catalytic reduction)
Seawater "scrubbers" could be another step.

For us IMO MARPOL Annex VI (TIER 2) is already standard, the EURO 5 and 6 are the next steps.

We have already to deal here with the only one existing SECA´s in the world, the Baltic, North Sea, and English channel!
And we have the only existing PSSA´s, here in and around Europe. So the lower US Standards are not interesting.

Be sure, as long as the "Grenaa" runs, it is permitted to run!

Regards
Richard

It would be nice if you would not manipulate your posts after receiving a reply!!!! And it is completely senseless to compare, or even mention, IFO 380 consuming monsters with our MGO or veggy oil sippers.

 

Very few people has in reality used these real marine engines low RPM high volumes engines in this discussion. I did. Not the Greena, but the ABC.
The problem is the misinformation. The 90% of diesel for yacht is a truck engine or car engine marinized. They have to pass all the emission and sell it at low cost by the thousand.
So what they do? weight is costly, an ABC 120hp is 5 tons, and cost with a Masson transmission is $180,000. The torque is the same as a high speed light engine of 400hp. at $30,000.
Reducing the casting to a minimum, higher revolution to give the HP and torque, is a way to LOWER the cost not to make the marine engine efficient. The electronic is cheap, and help to pass the emission the first year, after that they are not within the emission standard due to the fast wearing of all the components.
And the manufacturer know that yacht engine will brake down after 5000 hours.
A real marine engine must be design for 8000 hours a years, for a lot of years.
So who wants to pay for a real marine engine? Who want to design a boat with a real marine engine?. It will be a suicidal financial proposition for the majority of the motor boat which navigate few hours a year.
The boat market is peanuts compare to the transportation market, why bother with real marine engine. Even some cast in aluminum. And we still talking about marine engine? it is just ludicrous. And we are bombarded of misinformation through glossy magazine and incompetent boat journalist.

But here we talk about a real vessel, all weather, high range, year round working. And I am commenting about engines for this sort of vessel.

Daniel

 

Well put Daniel,

many contributors here just have the common boat engine in mind when making comments.
But we are well at home in the commercial marine market, and know what fits us best. (and our customers of course)

There was a comment by FF, that my client would choose the engine. No, never he does, I do not accept that. I install what I call best for the intended purpose, or the client goes elsewhere. He can choose the upholstery, thats enough.

I once built one of my own boats with Arie van Vulpen, Owner of Lowland yachts, which were known as "Swiss Watches" and "Pocket Megayachts". He did not even give me the choice on almost all systems! "I do what I can, and you pay what it´s worth" was his comment, "but I am the one who is responsible of the entire result" and "I do not trust what I have not proven"
..............................................
So we do that business! Anything else is a lie.
Needless to say, that was the best craft I ever owned, or have been on board. (all the ten times bigger yachts included)

Matt,

the seawater scrubbing can already reduce particles to a level beyond IMO MARPOL or EURO reg.s we encounter in 2016. The systems I mentioned above will do the rest if required.
I don´t bother about that.


Regards
Richard

 

Apex,

My ol boat ran a MAK, (old sub engine I believe, but it was new when built in 1957). I used to tune the engine from the exhaust pyrometers (we did not have fancy sensors then), old glass thermometers stuck in the exhaust manifold.

As each cylinder had its own injector pump, it was easy to adjust the rack to make the cylinders all work to the same temp.

The majority of engineers then advised me that the engine should have been setup so that the rack position was the main ingredient, not the exhaust temps, so all injector pumps were supposed to squirt the same amount of fuel, thereby balancing the engine. I respectfully disagreed, as my engine was running perfect, it was sooooooo smooth and started and ran instantly. My theory was that the temps said how much work each cyclinder was doing, and balancing these loads to be even was my priority, not making each pump put out the same amount of fuel, regardless of how much the cyclinder was working.

Was I right to adjust to exhaust temps instead of rack settings?

 

My engineer on the similar "Buckau Wolf" did it exactly that way (temp adjustment) and we had a very healthy, frugal engine. So, imho, yes!

 

It worked, didn't it?
There's no guarantee each injector pump was exactly identical. And it's generally the case in control theory that closed-loop control using feedback from sensors (ie. what you did) will yield better results than open-loop control (ie. set the inputs and leave it).

 

Indeed Matt,

that was machine building, not watchmakers art. Some tolerance was (and is) part of the design.

And I fully agree ont the closed-loop control.

Regards
Richrd

 

Now to the question I've been pondering lately (a decade or so) Can we take a truck diesel, rated for.. let's say 70hp at 3600rpm, run it at 1200rpm with ~28hp power output.. Well of course we can, but do we gain anything towards longer engine life etc other benifits of real marine diesels ?

With smaller boats there isn't much other choices except some old school engines from India.