Real Hybrid

Thanks Phil, very very interesting.

I don’t know whether to continue here or open a new thread, but the topic interests me a lot.
As written above, in the economy of a major refit or a new build, 0.5 l/h changes little, but the subject is very interesting.

I have always been convinced that a naturally aspirated engine at low rpm allows for lower consumption (not efficiency), since it can be run at few rpm with relatively large propellers and low slip. Coupled with a CPP you can have low prop rpm and low engine rpm, with the possibility (by reducing pitch) of facing sea and wind at full engine rpm (attention to propeller diameter, cavitation lurking…).
And this concept of low rpm → low consumption I believe is not contradicted by your writing.

Of course, the naturally aspirated engine at low rpm (or relatively low) will “suffer” a bit, it will be under its optimal regime for 80% of the time, but what does this realistically imply? A smaller pulley for the alternator? Gearboxes, does a PRM125 really absorb 5% less than a ZF25?

This is to say that a boat that absorbs 20 hp at 6.2/6.5 knots may need all of the (let’s suppose) 60 hp for sea and wind (and the propeller that would be optimized for 6.2 knots at 1400 rpm certainly won’t be at full throttle, I know…and here we are talking about CPP).

I don’t know, speaking only of consumption I am still convinced that 1400 rpm, maybe “rough” as a mechanical pump can deliver, are more convenient than 2400 even with common rail and VGT.

Thanks for the great discussion.

I hope my English is clear

 

A L F ,

I see your location is "None". Is that None, USA?

I also see in your opening sentence you are looking for

So the answer to this question

...sadly is 'no', as described by all the contributors above.

You are here to learn. What have you learned 'in a nutshell' ( briefly )?
In other words; what are you going to do?

 

Sorry, I did not fill out the profile correctly, I am writing from Italy.

I do not understand the tone of the message. If I asked a wrong question or broke the forum rules (I don’t think so), I apologize.

If all threads closed after the first reply, it would be a forum with little participation. Just as if everyone who asked something could make their wishes come true, it would be a much better world.

For now I have learned from Phil, with whom I believe I have an interesting discussion open, if it is annoying I apologize.

My goal is to get information (which is useful in forums) to decide where to direct my budget for the future.

 

As for economical, I hardly see how for most use cases, which Bluebell is trying to say above using a rhetorical style.

And there is a difference between economical and cheap. Economical means does it have a payoff? So, say your use case is a vessel to go around the world and not worry about fuel at all. You would evaluate the cost of this system versus an all fuel system and if the all fuel system has a problem of needing fuel where not available; the economics of the diesel hybrid cannot be beat.

But for most use cases, the diesel-electric option is layers of unneeded complexity and cost.

I cannot offer the detailed responses about how to achieve the goals, but I am an accountant and can easily talk about economics.

And the first thing to do when designing a boat is to understand the use case (SOR); not to design the propulsion system. Of course, this can take away lots of fun which is not my intent.

Anyhow, I will return to my rightful place as a quiet observer on the details of which I cannot offer squat.