Marine Propulsion: Diesel, Electric, Diesel-Electric or Hybrid? (2/2) 

¡Muchas gracias! Tu alabanza me está haciendo sonrojar. Me encanta España y paso todos los años una semana en Denia, alquilando un barco a motor por un día :-) (Traducción de Google)

Well, a Voith Schneider prop will definitely not be on my first boat (dinghy really) :-) More like two small electric outboarders, maybe 1kW or 2kW each. And yes, if I actually find the time (Covid is workwise over for me), I'll of course show it on RU-vid ;-)

Yes, the Voith Schneider prop was a fascinating revelation. Our Mr.Robert seems to do a lot of research !!

@@mumbaiverve2307 Of course I do my research before I confront my viewers with such lengthy videos ;-)

Thanks for the praise! The military will definitely be one of the first (ships/tanks/vehicles). For most others the initial investment is (currently) simply too high. There was a battery powered costal freighter announces and some solar/battery boots/yachts popped up. The latter are quite expensive and are only viable if you're happy with a cruising speed of a few knots (solar) or an endurance of a few hours (battery).

You're welcome! Cheers from Argentina Patagonia.

Thanks!

Well, bigger is in this case (almost) always better. That is more efficient in every way (energy efficiency, power to weight ratio, power to size ratio). Just an example I have at hand: Yanmar 1GM10: 6.6kW, 86kg, 410x485x554mm Yanmar 2YM15: 10kW, 113kg, 463x600x613mm So you get 52% more power with just 31% more weight (OK, 63% more volume in this case because we've switched from a single cylinder to a two cylinder, but you get the idea).

Sorry, forgot to add the link in the description. Here it is: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-z38cIBVdiV0.html

@@robertssmorgasbord Thank you; just watched that. The Voith Scneider prop. setup looks interesting, but its snag potential must be high. Overall, your two videos are a strong case for maintaining diesel in existing diesel-powered boats, and keeping an eye on diesel hybrid technology for new installations (perhaps with improved battery chemistry) in the future. Thanks for doing all the work on this.

@@KitLaughlin You're welcome!

Good question! I'm really not into automotive stuff, but depending on the size of the RV 30mpg (7.8 l/100km) should be possible without going through the hoops of a serial hybrid. In fact the advantages of a serial hybrid are greatly reduced in automotive applications, because you accelerate/decelerate often. The additional weight of the serial hybrid solution reduces your efficiency considerably there (you can't recuperate 100% when decelerating). I guess that's the reason you don't find any serial hybrids in the automotive market. BTW Fiat Ducato with high roof, 3 tons (metric) and 160HP just needs 6.8 l/100km (35mpg) diesel.

Thank you very much for that info! That's an application I didn't cover (or even thought about) in my video: Auxiliary engines for a sailboats. Could you please give me some more infos ... What power does your electric engine have? What's the top speed of your sailboat when under power? Regarding hydrodynamic charging: Do you plan to change to an electric engine with recuperation (yeah, I know, without auto feathering prop you constantly have that additional drag, and props with controllable feathering/pitch are expensive), or you you plan to use an extra, outboard like hydrodynamic generator? Anyway, love your Marcelina! Nice classic hull and simple, functional superstructure with clear lines (can't say much about the rig - I'm a motor vessel guy). I'm not a great fan of those modern sailing/motor vessels with superstructures that seemingly try to avoid any straight line or hard angle - everything has to be curved somehow. Best Regards Robert

@@robertssmorgasbord Sure... I replaced the 40 HP Volvo-Penta diesel with an Elco 40 HP (29 KW) electric motor. Either diesel or electric can get the boat to hull speed, which is about 7 knots. Although I never run the electric motor at top speed because I'm drawing 200 Amps (at 108 v) and my battery capacity is 200 Ah (21.6 kWh). If I drop down to 3.5 knots I'll only consume 30 Amps. In other words, I can triple my range by halving my boat speed. My battery/charging arrangement is a little complicated. I have two custom LFP batteries (51.2 v) in series, charged by a 15 A, 110 v AC charger... which is what I use when plugged into shore power. I also have 900 Ah of 12 v LFP batteries for my house bank that are charged by either an inverter/charger (shore power) and/or the solar panels and wind generator. I can then move that house battery power to the drive batteries via the inverter to two different chargers (in series) and into the drive batteries. Converting from DC to AC and back to DC through the inverter and chargers isn't the most efficient, but it works. Oh... and the generator is just a 2000 w Honda generator that can add about 15 amps (110 v AC). On it's own the generator could move the boat at about 2 knots, and the 5 gallon can I carry provides about 40 hours of continuous operation. So that's about 80 nautical miles of additional range. But like I said, the limited sailing I've done so far I haven't been away from the dock for more than a week, so I haven't needed the generator. On the drag device, the Elco motor doesn't allow regen, and anyway I have a feathering prop, so I will be adding a Watt & Sea generator that hangs off the back of the boat. It will put out about 100 W while sailing. This, along with my wind and solar, should be enough that I can comfortably run all my house loads (fridge, chartplotter, lights, etc.) and still arrive with all my batteries topped up after a long passage. I liked your analysis. My system certainly isn't the cheapest or most efficient, but it works for a tree-hugger like me.

@@dc14522 Thank you so much for all the info! And don't worry about your system not being the cheapest or most efficient. The important thing here is that it works for your application. Sure, the system would be a more efficient if you had all your battery capacity in a single (108V) bank. However, having two battery banks adds redundancy and therefore safety. If need be your 15A/110V charger could be used to run your engine from the 12V bank and and give you about 2 knots for maybe 6 hours (optimistic). If I might make a suggestion: Try to find a charger (power supply, voltage converter) for your 12V bus that can work off the 105V battery bank. That way you could continue to use the radio, plotter etc. even if your 12V battery bank fails / runs empty. Thanks again for sharing the info about your setup with me!

@@robertssmorgasbord You're welcome. I could run the 15 A/110 V charger from the house bank, but it pulls nearly 200 amps, which is more than my wiring can take. That's why I have separate chargers that allow me to "throttle back" the house bank to drive bank charge rate without setting my boat on fire.

@@dancourtney2816 I see. And good on you! Most people do have some idea that your wires need to be thick enough to handle a certain current, but are oblivious to the fact that a big enough battery (lead acid or lithium) can easily get a thin enough cable red hot, white hot or to melt.

It's certainly an interesting idea for implementing a cheap diesel-electric propulsion. For sure you're paying a premium for marine equipment because it is, well, "marine". Taking a run of the mill 3-phase industrial motor will for sure shave of some cost. And as long as we're talking inboard motors here, I can't really see any drawbacks. Same holds true for VFDs. The only problematic component might be the diesel generator. Those marine generators can handle a lot of tilting (as a ship rolls and pitches). I don't know what your standard stationary diesel generator would do after being tilted for hours +/-30° back an forth. I guess at least some models would have trouble keeping the lubrication going (oil, oil pump and oil sump). But you could always go with a diesel generator for street vehicles (semis/lorries). Those should be able to handle a bit of shaking.

@@robertssmorgasbord I guess there must be a hitch, or they would have done it by now :)

@@mumbaiverve2307 But your idea is still valid! E.g. for pontoons of lakes where you don't expect too much rolling and pitching, or for a houseboat.

First, thank you for the praise 🙂 Second, unfortunately there only very few (scientific/engineering) articles on that subject (google for "marine hybrid propulsion article") that I know of and I really can't recommend any of them. Also, as far as I know there's no textbook available on that subject. Third, I'm sorry but for privacy reasons I do not provide any contact information. I trust you'll understand. Sorry I couldn't be more helpful.

​@@robertssmorgasbord Thats fine and completely understandable 🙂

@@knut-magnusbrautaset8155 Thank you very much for your understanding!

@@robertssmorgasbord Quick question for the hybrid propulsion systems endurance: I assume you get 32 h by dividing 100kg fuel by 0.271g/kWh and then divide this answer by 11.5kW. Doesn't the battery contribute in some way? I am a bit confused as you later on say the hybrid is the superior alternative in regards of endurance.

@@knut-magnusbrautaset8155 Well, the battery would contribute if you charged it from an external energy source (plug-in hybrid, e.g. charging the battery with land power while being docked). In simply didn't include that option in my model. The endurance advantage of the hybrid in my model I talked about is based on the option to always operate the diesel engine (of the generator) at its peak efficiency, that is at certain RPM, respectively, power output. If you you need more power, you take the difference from the battery. If you need less power, you you use the difference to charge the battery. If your batteries are fully charged, you don't run the diesel generator at all. Of course there is a limit to this regime: If you operate your electric motor continuously at full power, at some point you'll have to operate your diesel generator at full power (with less efficiency). And of course there's recuperation: If you're operating some of the time under sail or you are anchored in a current, you can use the electric motor as generator and charge the battery. But, your idea of pre-charging the battery when docked makes absolute sense and would further increase the efficiency of the system.

You mean the first part? It's here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-z38cIBVdiV0.html (link also available in the video description).

You're the first 😄

Well, if my interpretation of your comment is correct (something like "Parallel hybrid is the way to go, you idiot!"), then for some applications you're absolutely right. I guess it won't help your emotional state if I point out (like I did in the video), that I didn't want to go into the serial/parallel hybrid stuff because of time.

Well, I think you are the second person to complain about that aspect of my videos. I guess the "talking hands" format is not for everybody. Anyway, I hope you found at least the information given in the video useful.

Talking hands was no problem for me.

@@tj6703 Thanks 🙂