Charging Up to Hybrid

  • 22 Nov 2019 23:51
    Reply # 8135482 on 8133077
    Anonymous wrote:

    I don't remember what made me decide but decide I did. To take a different direction. Costly but I'm enthusiastic.

    One of the reasons I have been dragging my feet on Hobbit's refit is the fact I hate diesel engines. It seems everyone has a story of grief concerning their diesel. How it broke down in the wrong place at the wrong time. Delays, delays. So many parts. What spares to have on hand? The noise, the smell, the dirt the mess....

    I've decided to remove my Yanmar YSB12 (10Hp) engine and replace it with a QuietTorque 10.00 Sport Electric Motor from Electric Yacht.  48V using eight 6V batteries in series, a type often used in golf carts, from Surrette, known in the US under the brand name Rolls. They are located nearby in Springhill. World wide, they have an excellent reputation.

    (Meanwhile, the engine is in good shape and will hopefully put life back into an ageing Contessa somewhere.)

    Propeller: 13 x 11 x 3, right hand turn.

    My 30' Benford dory has good space for batteries. They will displace the equivalent volume of 25 gallons of water. However, the diesel fuel tank can be modified to carry water. A bladder perhaps. There is another built-in tank meant for kerosene but not used, on the other side which could be used for water.

    I intend to buy a Honda EU2200i portable generator, fitted with a three-fuel adapter so it can be run on gasoline, propane of natural gas. According to Electric Yacht, Hobbit can be propelled by a 2Kw generator at 3 knots in calm water, indefinitely. Essentially, we are looking at a hybrid boat

    Where to store fuel? Working on it. Propane tanks could be stored on fore-deck, attached to forward side of the cabin bulkhead.

    My intended use is local and coastal cruising. Range is limited so one needs to "live within ones means." There will be solar panels. A wind generator, probably not.

    Anyway, it's all very exciting and I feel a renewed enthusiasm for this rather drawn out refit. I think I might try living aboard for a year and sublet my apartment. That will pay for the conversion.

      Pake' my NA29 has had an electric auxiliary motor for a number of years. 400 watts of solar panels OR 1000w/15A portable generic generator will propel Pake' at 3 knots indefinitely (if wind or sun are not available). If I could put 30 amps in with a larger generator I would increase speed a knot or so. Weight is 12,000 Lbs (on the scales) with only 5kw motor. Recommended size now is 10kw or more. I believe if you want full hull speed for length of time without overheating the motor, a larger motor or cooling, or both are in order. I would not hesitate to go offshore with extended cruising in mind with the set up I have now. The shore is the hard part. The electric motor is usually motor sailed off of the solar panels when every one else is ghosting with a big genoa or just motoring. The second use is to get in and out of the harbor in traffic.

      I have no needed maintenance other than cleaning the solar panels and have had complete reliability. My "best quality" set up including 4 x 8d batteries for 48 volts, 440 watts of solar panels , motor/transmission, larger 4 blade prop, larger Sevcon controller plus all the "best" bits, pieces and cables cost less than any 10 to 15 hp diesel system I could find. I did the whole switch on a mooring by myself. All the components are relatively small and light. The old dirty stinky md7a 's 400 lbs clean up was the hardest part.The little electric motor was a perfect fit.

      Also, my large 2x 6 volt Surrett (rolls) house batteries are still going very strong after 12+ years of use. They still look new inside and out. Rolls/Surrett  are almost impossible to get unless you are in the NE USA or in England. I believe they are made in Newfoundland but am not sure. I have been using SURRETTS for over 35 years. They come very highly recommended for wet cell batteries

      I think you would really appreciate the switch.

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    Last modified: 23 Nov 2019 21:12 | Anonymous member
  • 22 Nov 2019 21:37
    Reply # 8135410 on 8133077

    There is not a lot to add to what has already been said. I like electric, I think there is a lot going for it. However, I would say that unless you are looking in the 1000+ hp range, I don't think anyone has done the R&D to properly apply an electric motor to a smaller yacht. Some of the large freighters use an electric motor as a gearbox/shaft replacement and the whole drive from motor to prop has been engineered before the install.

    On almost any yacht system I have seen, the install is a  conversion (even on new electric from the factory boats). The boat starts out as an IC powered boat and the same prop is powered by an added electric motor/transmission which turns the prop at a speed appropriate for an IC engine. This is, in my opinion, a mistake that does not make good use of the electric motor's unique characteristics. In general, an IC engine has a useful range of RPM and the torque and HP are really only useful over a small range of RPM. This range is relatively high RPM and so a gearbox is most often used to lower the shaft rpm and the propeller is designed to run faster than otherwise best while the diameter is kept small so the IC can still turn it at idle. This set of compromises is well tested and has worked for years. The yachts have been designed around formulas that expects those compromises too.

    The Electric motor is not like that at all. An electric motor is "constant torque" from 0 rpm to a specific rpm and then constant hp above that. None of the formulas I have found for motor/prop sizing make any sense for an electric motor. It is amazing to me how well electric motors do work considering they are just dropped in place of an IC. An electric motor is much closer to a piston steam engine in needs. Use the biggest prop you can find for electric (one steam tug I know of uses an 8 foot diameter prop, top RPM 250). Make a bigger prop aperture if needed. Whatever pitch the prop for a IC is, the electric motor should be more. The reason a small outboard for a sailboat has a "high thrust" low pitch prop is to let the engine get up to it's highest power at 4500rpm or so... an electric motor has full torque at 0 RPM. Bonus with a higher pitch prop is that it causes less drag when sailing (assuming it does not fold or feather) and in high winds it will regen easily so as to help recharge those batteries.

    Notice I have given no exacts... this is because the R&D has not caught up with the lowering price of electric systems. There is no really efficient electric boat drive setup for small boats because no one really makes all the bits. Rather, parts made for IC setups are used off the shelf to keep costs down. So to use electric drives for a boat, it needs to be an experimental setup. Something that does not mind having parts swapped out to try and get the most out of it. I suspect that a properly designed boat drive with electric will use less power for the same speed but I also don't think any such animal exists.

    As far as gas powered genset compared to installed diesel... keep the diesel. The design life on small gas powered engines is small compared to a marine diesel, maybe 10% (this is not time to repair, but time to replacement). Add to the losses from converting to electric->dc->ac->dc etc, that the diesel will produce 20hp/hr/gal while the gas powered engine will produce 10hp/hr/gal. That is the diesel (all else being equal) will travel twice as far with the same size fuel tank as a gas engine connected directly to the shaft. On top of that, gas fumes are explosive and a gas puddle will catch fire with just a spark. Diesel fuel is much safer. Diesel is cheaper and available everywhere.

    Ya, I love electric but practical wins in the end.

  • 22 Nov 2019 18:49
    Reply # 8135112 on 8133077

    As usual with our forums lots of robust discussion going on here. I will put in my two cents worth based on experience. I can certainly see the potential attraction of electric power, and Kurt on Mehetibel seems to have made it work. But even in sunny New Zealand there are times when I would be concerned about the reliability of the electric engine when one really needs that power on a dark and stormy night. Sure, having a generator to provide back up power is an option, but that seems to be adding complication.

    Based on my outboard experiences with 'Footprints' an appropriate 4 stroke outboard would be my number one choice of auxiliary engine, provided there is a suitable and effective means of mounting the engine. On 'Footprints' I had 10 years of completely trouble free service out of the 9.9hp high thrust Yamaha outboard, and this with maintenance limited to the occasional oil and spark plugs change, and one water pump impeller replacement.

    With our current yacht  we inherited a 30 year old marinised 18hp Kubota diesel. For the first several months I regretted the shift back to a diesel engine and its complicated add-ins such as shaft seals, and the engine seemed a smelly old thing. However with some basic DIY maintenance the engine is now running well. I used a fuel system cleaner additive in the fuel which seems to have helped a lot with the performance of the motor, so now I am quite happy with the engine, and it is very quiet. I saw the exact same engine on a Kubota ride-on lawn mower a few weeks ago so I know I can easily find spare parts for the motor should they be needed.

    A well maintained and correctly installed diesel engine will be very reliable and can be depended on when the going gets tough.i have also had previous positive ownership experience with a 18hp Yanmar engine (2 GM), and a 10hp Sabb which was crank start only. Sadly these engines are no longer manufactured, but there are lot of good small marine diesels available. I would suggest that any failings with a fitted diesel engine are most likely the result of poor installation, and lack of suitable ongoing maintenance.

    That Sabb was also a rusty, smelly, dirty old monster when we first purchased the boat in which it was installed. But we cleaned it up, added an alternator for battery charging, and learned how to use the motor, and had 8 years of good service from it before selling the boat.

    Last modified: 22 Nov 2019 19:47 | Anonymous member
  • 22 Nov 2019 16:48
    Reply # 8134946 on 8133077
    Anonymous member (Administrator)


    of course I can, but I like to be able to start and run the engine 2-3 times each winter. Besides, I have now found another source for that petrol which is only twice as expensive as ordinary fuel, so will probably use that summer and winter, to keep Mr Tohatsu happy...


  • 22 Nov 2019 16:41
    Reply # 8134937 on 8133077

    Alternatively, Arne, you could just switch off the fuel cock as soon as you dock, leaving the engine running and run the carburetor dry while you are sorting out the docking lines.

    At end of season, drain the carburetor and use the drop left in your car or someone else's, maybe?

  • 22 Nov 2019 15:28
    Reply # 8134755 on 8133077
    Anonymous member (Administrator)

    So many new words...

    In his posting below, David Tyler introduces the term Displacement Activity to me ( least...).

    Join the JRA and learn fancy English. Now I had to look it up in the Cambridge Dictionary:

    Displacement activity:
    An unnecessary activity that you do because you are trying to delay doing a more difficult or unpleasant activity:

    “When I was
    studying for my exams, I used to clean the house as a displacement activity.”

    David also suggest that an electric engine could make sense on day-sailers with access to shore power. I surely am in that category, but even though I have quite a few outings every summer, the fuel consumption of my 6hp Tohatsu is miserably low: I filled the 10-12 litre tank early in 2017. Only this summer did I add another five litres. With so little use, my concern is rather to keep the carburettor from being clogged by old petrol, so after the season this year, I emptied the tank and filled on 5 litres of something called ‘alkylat’ petrol in my world. It is three times the price of normal petrol, but a clean carburettor and a soot-free spark-plug is a nice thing to have...


    To put the consumption in perspective: I replaced my old car for a new one only two days ago. That will cut the annual petrol consumption from about 480l to only about 290l.
    Sooo, I don’t worry about that 'gas-guzzling' Tohatsu...

    Last modified: 22 Nov 2019 15:43 | Anonymous member (Administrator)
  • 22 Nov 2019 10:42
    Reply # 8134483 on 8133077

    I don't understand the reasoning, Jim. You really want to exchange a relatively reliable, relative safe internal combustion engine for a less reliable, less safe one? There's a reason why diesels are used in almost all commercial road transport and seagoing vessels - give them clean fuel, air and water, and they keep on going for ever, without any safety concerns.

    Hate is too strong a word. Of course, one can dislike having to use an engine at all (I do), but most of the time, if it's an auxiliary to a sailboat, it can sit there unused and out of mind. Spend some of the cost of an electrical propulsion system on getting a professional aboard to put the existing diesel into tiptop shape with state of the art installation, and then hand over all routine maintenance to them; that would be a better investment.

    There's only one scenario where electric yacht propulsion makes sense: where it's possible to dispense with a fossil-fuel powered engine entirely, by plugging into shore power for recharging, and using the electric power only to get in and out of a tight marina for day sailing. That works. For any scenario in which the yacht has to generate its own electric power, it doesn't.

    I can understand why one might want to use propane as a fuel. It's the fuel of choice for fork lifts that are used in warehouses, because the emissions are less toxic than with diesel or gasoline. So why not just cut out the electric bit, and put in a propane-fuelled motor? OK, you're sailing in a floating bomb, but a lot of people seem to accept propane aboard for cooking purposes. A car can be converted in a day, to run on LPG instead of or as well as gasoline; so could a gasoline motor installed in a boat. But why do it, if the diesel is in good shape?

    Overall, though, all I can see is a search for further reasons not to actually get this boat out sailing. Sorry, Jim, but I think this seems like displacement activity.

    Last modified: 22 Nov 2019 16:07 | Anonymous member
  • 22 Nov 2019 09:11
    Reply # 8134448 on 8133077
    Anonymous member (Administrator)


    Well, if your diesel «is in good shape», as you say, why on earth sell it? This is a sure way of keeping you high and dry for another long time. Is that what you want?

    Unless the diesel is rusting away from you, I would advise you to keep it. CO2-wise diesel engines are more efficient than a petrol engines, and after all, you decide how much, and how hard to use it. Hobbit II is a sailboat.

    If I were to take over a sailboat with a diesel, and wanted to improve its reliability, I would...

    1.      ..install two diesel filters in parallel with cocks to choose one or the other. This lets one replace a clogged filter while the engine is safely running on the other one.

    2.      In case the boat is sea-water-cooled (with or without a heat-exchanger to freshwater), I would have two water inlets, one on each side of the keel. In case an inlet is clogged by some plastic or whatever, the other inlet will ensure cooling.

    Note: Both the fuel filters and the seacocks for the cooling water inlets must be easy to access. 

    It is easy to decide ‘I don’t like diesel’, but it is quite a job to convert the boat. I have seen one friend going along this path, just because his (single) fuel filter was blocked. It turned out to kill the whole rig conversion project, and he ended up selling. He is now just sailing his armchair...



    Last modified: 23 Nov 2019 08:56 | Anonymous member (Administrator)
  • 22 Nov 2019 01:58
    Reply # 8133903 on 8133712
    Jim said:

    The problem I see with using DC to directly run the motor, is, what do you use for a throttle? I'm sure someone out there who are more conversant on this topic than I.

    I think my question was not very clear. I should have asked if you intend to power the DC motor controller with the DC output of the generator. As you say the Honda DC power output is much lower than the AC spec.

    I suppose if you have a 48v motor and a 12v DC output from the generator then the AC is the only practical power source.

    Will you use a battery charger to provide power to the motor controller when you are using the generator for propulsion power?

    Last modified: 22 Nov 2019 04:04 | Anonymous member
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