Page 1 of 2 12 LastLast
Results 1 to 35 of 49

Thread: Diesel/Electric drive?

  1. #1
    Join Date
    Sep 2010
    Location
    Bainbridge Island WA
    Posts
    2,892

    Default Diesel/Electric drive?

    There was some serious thread drift getting started up in the Acorn to Arabella thread so I thought I'd start something new down here.

    I know big boats/ships like the the Washington State Ferries are diesel electric but has the technology trickled down to smaller privater-sized (not super-mega yacht) boats?

    in 2007 this came out: https://www.yachtingmagazine.com/diesel-electric-drive

    What is the current state of the art?

    I'm a sailor with an old outboard but motor-curious.
    Steve

    Boats, like whiskey, are all good.
    R.D Culler

  2. #2
    Join Date
    Mar 2011
    Location
    Mukilteo, WA
    Posts
    2,407

    Default Re: Diesel/Electric drive?

    Thanks for containing the thread drift.

    Electric and Deisel/electric boats are super cool, but in my opinion are totally wrong for a world-cruising sailboat.

    They are perfect for a boat that can tie to the grid every night to replenish with relatively clean power. For a boat that will be off-grid all of the time, they make almost no sense. Yes, you can have a generator big enough to motor continuously, but it will be at a considerably reduced efficiency over a direct drive due to losses, and at considerably reduced power over a normal setup. (think unable to fight against a current at a critical time.) Chances are you will find yourself running the generator at anchor often to recharge the big battery bank (no way solar/wind will keep up on a ketch like Arabella.) There is no sin greater than running a generator in an anchorage in my book.

    So I think it has a place, is super intriguing for the future, but the batteries and regen technology are just not there yet if you don't connect to the main power grid.

    For a boat just motoring in and out of a marina for summer evening sails, electric power would be perfect.

  3. #3
    Join Date
    Feb 2002
    Location
    Shubenacadie NS
    Posts
    4,601

    Default Re: Diesel/Electric drive?

    I think regen needs a bit of tweaking but isn't as far off the mark as you feel it is. I'm hoping that's the case anyway because I'm banking (pun intended) on battery tech and regen tech to be where it needs to be by the time I'm ready to launch my boat. To the point where I think I'll design the engine space to be removable so if I find I don't need the engine, I can remove it and convert the space readily to something like tool storage or some other useful space. I'm glad there's now a diesel electric thread. I'm hoping to move away from diesel toward only electric. Hopefully it works. There's time for improvement before I need it but that's where I'm aiming to be.
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
    -Henry David Thoreau-

  4. #4
    Join Date
    Mar 2011
    Location
    Mukilteo, WA
    Posts
    2,407

    Default Re: Diesel/Electric drive?

    Are you thinking about a cruising boat? Looking at most long range cruising boats that have been out there a while, they are covered with solar panels, have two wind generators, tow a water generator, and still have to pack a diesel generator. And that is just to power their house loads!

    Propulsion is a whole order of magnitude bigger than house loads, I just don't see a way to generate enough electricity without burning diesel. We could put real numbers to it. A big cruising solar array might be 500W, in the tropics you might get 80% of that over 10 hours per day. So about 333 amp/hours of energy each day at 12V.

    Your electric motor is maybe 10kW, which is undersized compared to diesel, but that is the game. To motor to a new anchorage for 6 hours at half throttle would require 2500 amp hours (at a perfect efficiency, assuming 12V). So if you never use any house loads, you can motor a bit once per week of solar recharge time. You will never motor for 10 hours into a head sea. And you have an area of ugly panels 4 ft by 8 ft or more.

    Once you factor in efficiencies and losses and real world issues it starts to look even worse. I just can't see how it pencils out without diesel or shore power.
    Last edited by J.Madison; 03-22-2019 at 02:01 PM.

  5. #5
    Join Date
    Oct 2015
    Location
    Kiel, Germany
    Posts
    233

    Default Re: Diesel/Electric drive?

    Diesel electric is a standard populsion system for more specialised vessels. Anything that has big load variations and/or big electrical demands. Ferries, cruise liners, mega yachts, research vessels etc. Closer to home, Laurie McGowan is a big proponent of electric and hybrid propulsion in the WoodenBoat Sketchbook series. But to my knowledge it is most always for local short distance hopping (Boxer) or light, sleek craft.

    I'd like to adress Daniel's (Sailor) post regarding energy autonomy/hydrogeneration.

    A little searching brings up the following: a functional, high tech turnkey solution from Oceanvolt.
    - Podded electric drive
    - good hydrogeneration thanks to a sopisticated folding prop
    - seriously expensive: 55,000 for a 20,000 pound displacement boat
    - the hydrogeneration power curve is non linear. To get within striking distance of being energy independent, you need to sail faster than 7 knots.


    Dedicated hydrogenerators? Sure. Watt and Sea POD600.
    - podded or at the end of a foil meant for a fashionable, wide transom
    - fixed propeller with a pitch that would only produce froth if you'd dare using it for propulsion
    - again, the same non linear power curve. Physics don't lie. With the biggest prop and the biggest pod, 5 knots of boat speed scrapes at 100W, their lower limit for autonomy.

    Now, let's put some of that in perspective for our circumstances: wooden hull, tending towards traditional, likely full displacement.
    - Boat speed is the first crux. You're lucky if you average 6 knots, that's at the very bottom end of the power curve.
    - Full displacement is the second. These boats need quite a bit more power to move than your typical modern fin keel rocket.
    - Compatibility is the third. The available tech looks to be designed with a specific boat in mind. And that boat looks a lot more like an IMOCA 60 than a Colin Archer. Integrating a pod or a transom hung foil with a wooden hull? Sounds like a challenge.
    - Cost, Complexity...

    It's about 10 times more expensive than a comparable diesel installation. Plus a lot of compatibility headaches, and after all thet you're scraping at the lower limit of autonomy if you're lucky. I don't see it.

    But what about using the engine and standard prop for regeneration? No. Not even with dual engines and big props away from the centerline for good inflow? Still no. Why?
    Because inflow is not your problem. Speed is. What the hydrogenerators are doing is striving for the highest possible shaft speed, with an extremely low pitch propeller and aiming for high boatspeed to begin with. That's where the juice is.

    Now a fixed sailboat propulsor, especially on a displacement boat, is exactly the opposite. Low shaft speed, coarse pitch. Which makes it so that if you drag it through the water, it hardly spins at all. At least where a dynamo is concerned.
    Put in a folding prop, you still won't get close to the efficiancy of a dedicated hydrogenerator. Because the next problem is the shaft. The beauty of a podded installation is a nearly nonexistent shaft length. The typical fixed installation on a traditional boat has feets and feets of shaft length. With multiple bearings. Spinning a shaft like that at say 3 times the rpm of the engine at full speed is a big headache.

  6. #6
    Join Date
    Mar 2007
    Location
    East Quogue,NY
    Posts
    17,897

    Default Re: Diesel/Electric drive?

    There are some mid-size power cruiser builders (+/- 35' LOA) that one can buy with hybrid systems --diesel electric. These are offered on request: I know Beneteau did a Swft Trawler 35 with a Cummins/ ELCO ; diesel / electric setup. The Greenline 36 is another. Use the electric for in and out of the marina, no wake zones, slow cruising of any kind, etc.

    Once out in open water, or when batteries die, or when you just feel like it, run on diesel at higher speeds, or enjoy the quick, "refill and go," IC propulsion delivers.

    Boat's of this sort usually have a genset anyway, these days, so that is in the mix as well, and described accurately by Mr. Madison above. Boat owner profiles all vary by how they might use the combination of power. Depends on where one's boating location is and what kind of cruising one wants to do.

    The real hold-back is cost. You'll pay tens of thousands more for the boat versus the same boat powered just by an IC propulsion system. Even for one with wherewithal to purchase a $300K boat, another $50K is real money. And, because of the size of the battery banks required, the hybrid boat with have less stowage aboard and poorer servicability due to more cluttered bilge spaces ( where the battery banks live), compared to just having the diesel. Performance and efficiency under IC power may also be less than the IC--only boat because of the weight of the batteries decreasing the boat's power-to-weight ratio and causing it to sit lower in the water.

    Kevin


    ( Standard disclaimer):
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  7. #7
    Join Date
    Mar 2009
    Posts
    1,555

    Default Re: Diesel/Electric drive?

    I had a buddy with a diesel/hydraulic drive on his 40 ft steel sloop. Engine placement was very flexible, he could put it anywhere it could fit. The hydraulics were useful for anchor winches and other applications as well. Hydraulic motors are tiny, so are easy to mount and align, and clutches, reverse and reduction gears are not necessary.

    Efficiency was an issue, as hydraulics are only about 80% efficient (90% pump, 90% motor).

    I don't see why batteries are required for a diesel/electric setup. The advantages would be similar to the hydraulic one, in terms of engine placement. Efficiency would be higher (95% generator, 95% motor).

  8. #8
    Join Date
    May 2016
    Location
    Ottawa, Canada
    Posts
    311

    Default Re: Diesel/Electric drive?

    We looked at this a number of years ago and decided for a direct drive for all the points listed above.

    We will be turning a fairly large sized 3 blade prop, and plan to get some regeneration while under sail. I've exchanged with another sailor with a similar sized boat as ours (and prop) and he could get 600 watts or so. It doesn't sound like much, but that's enough to keep our systems running while sailing.

    Going with an electric motor turning the prop means you can deliver more torque at lower RPMs, so you can turn a larger diameter propeller. I think our boat is just a bit to big to make this economically viable at the moment, but there seem to be many EV parts that could used for a smaller vessel at a reasonable cost.

    Having a generator sized to allow motoring continuously at say half of hull speed and the batteries in case you needed a little extra every once in a while.

    It is a sailboat, so you should be sailing most of the time right ?

    Cheers,
    Mark
    Last edited by Mark0; 03-24-2019 at 07:05 AM.

  9. #9
    Join Date
    Nov 2004
    Location
    Port Townsend WA
    Posts
    12,814

    Default Re: Diesel/Electric drive?

    Here is a company that can answer all of your questions concerning all forms of electric boat drives. This article in the LA Times will fill you in.
    If you like what you see then you might want to contact them. Even though they primarily build electric launches, they are capable of producing any kind of electric drive required for the customer.
    Jay
    https://www.latimes.com/archives/la-...204-story.html

  10. #10
    Join Date
    Sep 2017
    Location
    Denmark
    Posts
    65

    Default Re: Diesel/Electric drive?

    Very interesting thread! I am planning to equip my 32ft gaffer with an electric pod drive, when I get that far.. But I have to make some decisions already know in the construction of the stern. I have sailed 20+ years with diesel engines with all the joys that come with not having a brand new or well serviced engine. Noisy and smelly, but the biggest argument for looking into electric drive for my new boat are the plans for out phasing diesel in Denmark by 2030. Prices for fuel will probably get higher and higher over the coming years. It would be strange to build with bronze and white oak for longevity, and then install a powerplant that is very expensive to use in 10 years.

  11. #11
    Join Date
    Jul 2013
    Location
    Aquitaine
    Posts
    1,050

    Default Re: Diesel/Electric drive?

    There is always 'diesel' produced from waste veggie oil. Quite a few run their cars on it in UK.

    Diesel/hydraulic only makes sense for placement as the oil gets hot and needs cooling. If you want winches etc, then a pump on the main motor gives that and leaves the simple, efficient, shaft drive alone.

  12. #12
    Join Date
    Oct 2015
    Location
    Kiel, Germany
    Posts
    233

    Default Re: Diesel/Electric drive?

    Quote Originally Posted by Galathea View Post
    Very interesting thread! I am planning to equip my 32ft gaffer with an electric pod drive
    A pod? Why exactly. With a traditional hull, Id say you're much better served with a shaft through the centerline and prop in an aperture. That's where the load is best transferred into the hull structure. The hull side of a plank on frame boat is not equipped for that sort of point load. Nevermind the fact that a pod requires a big, stable flange surface to bolt to and is essentially a big through-hull. And then it's sticking out in the open, unprotected. On a fin keel, for which these things are designed, it rides in the wake of the fin.

    Do you have a specific pod in mind? Have you talked with Gartside about it? Very curious.
    Last edited by MoritzSchwarzer; 03-25-2019 at 02:53 PM.

  13. #13
    Join Date
    Feb 2002
    Location
    Shubenacadie NS
    Posts
    4,601

    Default Re: Diesel/Electric drive?

    I suspect it depends on the hull shape. Bolting to the deadwood either side could be solid if the shape of the hull allows for it.
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
    -Henry David Thoreau-

  14. #14
    Join Date
    Mar 2011
    Location
    Mukilteo, WA
    Posts
    2,407

    Default Re: Diesel/Electric drive?

    Quote Originally Posted by Galathea View Post
    Very interesting thread! I am planning to equip my 32ft gaffer with an electric pod drive, when I get that far.. But I have to make some decisions already know in the construction of the stern. I have sailed 20+ years with diesel engines with all the joys that come with not having a brand new or well serviced engine. Noisy and smelly, but the biggest argument for looking into electric drive for my new boat are the plans for out phasing diesel in Denmark by 2030. Prices for fuel will probably get higher and higher over the coming years. It would be strange to build with bronze and white oak for longevity, and then install a powerplant that is very expensive to use in 10 years.
    How will you recharge when away from a dock? Or will you primarily sail from a marina with power supply? I am very certain Denmark's commercial fleets will not all be electric in 10 years. Maybe diesel/electric, but that's just diesel at twice the install cost.

  15. #15
    Join Date
    Jan 2010
    Location
    Northern Europe
    Posts
    10,243

    Default Re: Diesel/Electric drive?

    I crunched the numbers for a small offshore cruiser running a diesel electric hybrid system, with the motor running 16 hours charging the main battery pack, and then running under electric for 8hrs. Given the high initial cost of the hybrid system to start with, and a large Li-Po battery bank which would need replacing every few years, it was found to be more cost effective just to run a bog standard diesel.

  16. #16
    Join Date
    Mar 2019
    Location
    Bulgaria Plovdiv
    Posts
    2

    Default Re: Diesel/Electric drive?

    Здравейте, stromborg Искам да споделя с вас, че си купих електрически сърф https://awakeboards.com/, и наистина технологията е доста напреднала. Препоръчвам на всички да обръщат много внимание на електрическите двигатели като цяло. Надявам се, че сте ми помогнали. Приятен ден!

  17. #17
    Join Date
    Sep 2017
    Location
    Denmark
    Posts
    65

    Default Re: Diesel/Electric drive?

    I guess it all depends on how you sail your boat. My last boat, which was a double ender of around 8T displacement had a 1 cylinder MD10A which had 10hp when new; maybe.. It was used for getting in and out of marinas and the occasional 2 hour motor cruising if we were late for a planned anchor spot and there was no wind..
    I thought of carrying a little "handbag sized" generator if needed, but the 6 hour range with 6 knots for the 10T boat I am building will be just fine for me. There will probably be dispensations for commercial crafts for a while, but there will absolutely be high fees for leisure crafts in 10 years time. But the main argument is the dream of quiet clean running.

    In terms of price I can install a complete new electrical system for ⅔ of the price of a complete new diesel system.

  18. #18
    Join Date
    Mar 2007
    Location
    East Quogue,NY
    Posts
    17,897

    Default Re: Diesel/Electric drive?

    lidabrillon






    Junior Member







    Mar 2019Location
    Bulgaria Plovdiv
    Posts1
    Re: Diesel/Electric drive?

    Здравейте, stromborg Искам да споделя с вас, че си купих електрически сърф https://awakeboards.com/, и наистина технологията


    Google has a translate function:

    Google има функция за превод:



    Hi, stromborg I want to share with you that I bought an electric surfboard https://awakeboards.com/, and really the technology is quite advanced. I recommend that everyone pay much attention to electric motors as a whole. I hope you helped me. Have a nice day!
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  19. #19
    Join Date
    Feb 2004
    Location
    Texas
    Posts
    10,838

    Default

    Quote Originally Posted by Galathea View Post
    I guess it all depends on how you sail your boat. My last boat, which was a double ender of around 8T displacement had a 1 cylinder MD10A which had 10hp when new; maybe.. It was used for getting in and out of marinas and the occasional 2 hour motor cruising if we were late for a planned anchor spot and there was no wind..
    I thought of carrying a little "handbag sized" generator if needed, but the 6 hour range with 6 knots for the 10T boat I am building will be just fine for me. There will probably be dispensations for commercial crafts for a while, but there will absolutely be high fees for leisure crafts in 10 years time. But the main argument is the dream of quiet clean running.

    In terms of price I can install a complete new electrical system for ⅔ of the price of a complete new diesel system.
    Would be interested in knowing the details of your electric engine and batteries.

  20. #20
    Join Date
    Dec 2016
    Location
    EU
    Posts
    525

    Default Re: Diesel/Electric drive?

    I would be also interested in the details. Right now it can only be done by using second hand production EV batteries. 10 years from now I don't know.

    Phasing out diesel in 10 years has to be taken with a grain of salt. The engine itself will stay. The fuel it will use will probably not be the same as today. There is a move towards what is called "synthetic fuels". This are fuels designed to provide clean combustion and maximum performance. Their origins can be from mineral oil, vegetable oil or "air to liquid". Basicly similar to engine lubrication oils sold now as "synthetic".

    Anybody believing that the economy can move away from mineral oil, gas and coal in the near future is dreaming, there simply is no alternative right now. But can improve the usage of mineral resources, and their direct impact on the environment.

  21. #21
    Join Date
    Mar 2015
    Location
    Granby, Massachusetts
    Posts
    418

    Default Re: Diesel/Electric drive?

    Quote Originally Posted by stromborg View Post
    There was some serious thread drift getting started up in the Acorn to Arabella thread so I thought I'd start something new down here.

    I know big boats/ships like the the Washington State Ferries are diesel electric but has the technology trickled down to smaller privater-sized (not super-mega yacht) boats?

    in 2007 this came out: https://www.yachtingmagazine.com/diesel-electric-drive

    What is the current state of the art?

    I'm a sailor with an old outboard but motor-curious.





    Thanks for starting this!! I'll be following along for sure!! Super interested in what folks have to share!
    ACORN TO ARABELLA
    For additional info on this project:

    www.acorntoarabella.com
    https://www.youtube.com/channel/UCAi...WB1xCp6uuUo0VA

  22. #22
    Join Date
    Dec 2016
    Location
    EU
    Posts
    525

    Default Re: Diesel/Electric drive?

    Moritz said it all, the boat is to small and to slow for long range electric drive (pure or hybrid) autonomy. What is possible is short range low power auxiliary assistance for entering port with dockside charging and generator assistance. Going lithium allows for more range/power but you are still locked to marina charging.
    You have to face the fact that for extended cruising Arabella is going to be a generator boat. There is no space for meaningfull solar. You can fit a propshaft generator that will give you 50-100W. It will be a custom job but could cover your house electricity use while on passage in the trades. The moment you anchor you are back to energy nazi mode or generator. The only way to avoid a dedicated generator is by going lithium and having a big enough generator head on the main engine.

    As designed your boat was not intended for diesel power, high electric loads, indoor shower, propane or any other modern lifestyle necesities. We have some help from modern inventions like LED lights and lithium batteries but the base limitations still apply.

  23. #23
    Join Date
    Apr 1999
    Location
    Hyannis, MA, USA
    Posts
    47,512

    Default Re: Diesel/Electric drive?

    In commercial applications, hybrid tug boats are coming along. They have huge electric motors driving the props with generators providing power when there is a load and batteries when light. An added plus is that electric motors have their power through almost all the rpm range.

  24. #24
    Join Date
    Sep 2017
    Location
    Denmark
    Posts
    65

    Default Re: Diesel/Electric drive?

    Krautler and Torque(not sure the spelling is correct) has some interesting products, but here in Denmark there are also a couple of companies that put together "packages" with more or less "off the shelf" products. The control unit is sophisticated but the rest is just motor; batteries and wiring.
    In my 20 years of sailboat sailing I can only think of 2 times where I have motored more than 5 hours; 1st time bringing an almost sinking boat back through waters where I had no map for(swedish east coast; lots of rocks and cliffs) and one time with a broken boom, where I had to be at work the next morning. (I didn't make it) I would always want some kind of auxiliary power on my boat, in order to get out of harms way if crossing commercial shipping lanes and for the psycologigal effect after drifting backwards for hours with no wind(Plus the fact that the major harbours around Copenhagen doesnt allow you to enter with sails only) So if I can avoid a leaking stern tube and move forward with clean green energy, I would be happy.

  25. #25
    Join Date
    Feb 2002
    Location
    Shubenacadie NS
    Posts
    4,601

    Default Re: Diesel/Electric drive?

    I think we're all in agreement that modern electrical auxiliary powered heavy cruising sailboats are not happening quite as we wish they could right now. However, where will battery technology be in 10 years? 5 years? Next year? Elon Musk and many others are putting an awful lot of money into battery R&D and who knows what might come of it in the next 10 years. The way electric cars are progressing and becoming more prolific, I suspect we'll be pleasantly surprised in 2029 (the year I will be eligible to retire, by the way). Maybe something will come of small alternators to make them more efficient and put out more power. I truly think batteries will be something very different in the future and that's where the big change will be. I would like win screws on my boat that regenerate under sail when moving fast enough through the water. I envision some solar and a pair of wind turbines. Solar is another thing that may change. The state of the art tech is starting to incorporate PV cells into flexible cloth like material. A sailing vessel who's entire suite of sails is PV could expect to generate quite a bit of electricity if PV sails ever become a thing.
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
    -Henry David Thoreau-

  26. #26
    Join Date
    Dec 2016
    Location
    EU
    Posts
    525

    Default Re: Diesel/Electric drive?

    Galathea the problem you will face is that right now you can not buy 6h at 6 knots for 10 000 euros and fit it in a small vessel without resorting to sh EV batteries. If you can live with the risk of potentially dangerous batteries then yes, it is possible right now.
    As for leaking sterntubes dripless stuffing boxes already exist.

  27. #27
    Join Date
    May 2016
    Location
    Ottawa, Canada
    Posts
    311

    Default Re: Diesel/Electric drive?

    Sailor ,

    I think we are a bit closer than you think. If I was starting from scratch today I might have been swayed to a diesel electric system.... Which is funny from the guy with the big slow turning diesel, manual windlass and very limited electrical systems.

    Cheers,
    Mark

  28. #28
    Join Date
    Feb 2002
    Location
    Shubenacadie NS
    Posts
    4,601

    Default Re: Diesel/Electric drive?

    I'm still in the planning stages of my build. Little bits and pieces but irrelevant to the hull. Belaying pins, deadeyes, that sort of thing. Cruising schooner.
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
    -Henry David Thoreau-

  29. #29
    Join Date
    Sep 2010
    Location
    Bainbridge Island WA
    Posts
    2,892

    Default Re: Diesel/Electric drive?

    I'm curious to see where we go in terms of batteries. The 6hp outboard in use on Marianita mostly gets us out of the slip and outside Eagle Harbor in 15-20 minutes with the same coming back in. Shore power is available at my slip so I could recharge pretty easily most of the time. But I also have my annual voyage to Port Townsend, about 40 nautical miles each way under power. Over the years I have had some spectacular sails on this trip but we have been reduced to motoring far more than I'd care to admit. That little Tohatsu while get me there on less than 3 gallons of gas at just over 4 knots, making it hard to justify the investment in an electric system. Maybe in 5 or so years when I'm ready to start the next boat technology will have come along to a point where it makes more sense.

    Who knows what kind of positive effect going forward with the Green New Deal might have for us?
    Steve

    Boats, like whiskey, are all good.
    R.D Culler

  30. #30
    Join Date
    Mar 2011
    Location
    Mukilteo, WA
    Posts
    2,407

    Default Re: Diesel/Electric drive?

    The latest WB issue reports that the Western Flyer plans to have a hybrid setup, with 1MW of battery capacity! (Since when is battery capacity measured in watts anyway?)

    They also plan to have two 500 hp diesel generators, and most telling, they are hoping for a mega-corporation to sponsor the setup and buy it for them! They estimate it will cost as much as the rest of the boat combined.

    Getting 40 miles or so of propulsion without burning diesel is pretty cool, but for a boat that plans to range from Mexico to Alaska, 40 miles is not very far and there will not be infrastructure very often capable of providing 1MW of power to a harbor plug for recharging.

    I would hazard a guess that the ecological impact of the hybrid setup is considerably worse than that of a pure diesel system. The batteries are nasty toxic things to produce. While the energy they provide does only require half the carbon output of diesel, for the long passages when they are burning diesel anyway it is 10 or 20% less efficient than a direct drive. I don't think it pencils out from a carbon standpoint, and it definitely doesn't work from a cost standpoint.

    As a development platform it could be pretty cool though, if the mega-corp comes through.

    That said, a boat of more modest scale that always sails and returns to marinas could make good sense for an all electric setup today. For longer range boats that want to stay off the grid, its not just batteries we are waiting on, the regen technology is not there either. Solar sails might do it. Regeneration from the propellers never will. To get enough energy to have motor performance like we are used to with a diesel, you would have to create such a drag that no sailor would tolerate it, particularly on a long passage. For a boat that only intends to motor infrequently, and for short duration, propeller regen could work- but it would be hard to feel like the system wasn't handicapped.
    Last edited by J.Madison; 04-01-2019 at 02:23 PM.

  31. #31
    Join Date
    Sep 2010
    Location
    Bainbridge Island WA
    Posts
    2,892

    Default Re: Diesel/Electric drive?

    What if we get away from diesel and look at gasoline? The Prius Hybrid seamlessly shifts between modes in fairly small package.
    Steve

    Boats, like whiskey, are all good.
    R.D Culler

  32. #32
    Join Date
    Mar 2011
    Location
    Mukilteo, WA
    Posts
    2,407

    Default Re: Diesel/Electric drive?

    Diesel has more energy density than gasoline, so I don't think that would help much. The seamless start/stop could work with either fuel, but on a boat there is no braking regeneration or idle time at stoplights like with a Prius.

  33. #33
    Join Date
    Mar 2007
    Location
    East Quogue,NY
    Posts
    17,897

    Default Re: Diesel/Electric drive?

    I agree, J. Madison, you are correct. There is a ways to go.

    Battery's are also nasty to dispose of, a thing that certainly makes the enterprise less carbon friendly.

    As for propellers providing regen? A prop, the thing that pushes a boat, is, ironically, the biggest drag-producer of the boat. It is like dragging a disc the same diameter of the prop. As speed increases ( in order to increase charging output) drag goes up as the square of speed. So, that is a losing game as far as I can see.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  34. #34
    Join Date
    Mar 2009
    Posts
    1,555

    Default Re: Diesel/Electric drive?

    Hybrid cars work because the loads vary so much. From zero stuck in traffic, to 5% at city speeds (all electric), to 25% at slowish highway speeds. Priuses seem to run off the gas engine above 50 MPH, although there will be some regen coasting down hills and such like, and the electric motor is there for passing power. None of this is useful on a boat.

    A boat is a constant load. Many boat engines adapted from car engines are rated and run at about the same power as used by a car at highway speed, so they will last. Regen from the prop may not be worth the reduction in speed under sail. So why bother with batteries at all? Use the diesel-electric to put the engine wherever you like, and the motor wherever it fits best, on a pod, perhaps, with only cables going to it through the pod flange.

    So, the diesel engine costs the same. The generator will be much bigger than usual for this type of vessel, so more costly. The pod/motor will be an extra cost. On the savings side, there will be no reduction gear required, although some reduction will be needed in the pod. Batteries will be normal size for domestic use on the boat. There will be no cutless bearing or shaft to leak, although the cable through-hull will have to be sealed very well.

  35. #35
    Join Date
    Mar 2017
    Location
    Melbourne, Victoria, Australia
    Posts
    2

    Default Re: Diesel/Electric drive?

    Long time lurker, first time poster here. I’m investigating options for diesel/electric myself at the moment.

    Nigel Calder did a great write-up on the pros and cons of hybrid propulsion and how the numbers stack up - well worth a read if you haven’t already.
    https://www.passagemaker.com/technic...science-part-1
    https://www.passagemaker.com/technic...pulsion-part-2

    Key takeaway, if you’re considering a conversion purely for the sake of fuel efficiency then you are likely better off sticking with a conventional diesel engine as any efficiency gains probably won’t be enough justify the additional cost. However there are other motivators such as abundance of electrical power to run heavy loads, being able to reclaim space from the engine room and noise reduction, which can also be good reasons to consider hybrid drive.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •