Electric Drive

  • June 25, 2015 6:59 AM
    Message # 3403821
    Deleted user

    Hello All,

    As Bud has told me more than once "it's not if, it's when" with regard to my Volvo MD11.

    I'm doing research on going with electric drive/hybrid a la the Toyota Prius. I thought I would see if anyone has had similar thoughts and what the result of your research has been. I believe there is at least one W32 out there with electric drive.

    Thanks in advance.



  • June 27, 2015 1:20 PM
    Reply # 3406971 on 3403821

    Do you use your engine 10 minutes per day to get in/out of the slip?  Do you use it 48 hours straight on offshore passages with no wind?

    The practicality of electric drives depends entirely on your requirements.

  • June 27, 2015 1:28 PM
    Reply # 3406973 on 3403821

    Whoops. Forgot to pass the info. Here it is.  Neither I nor WOA vouch for these claims.

    Cc: Mike@electricyachtssocal.com <Mike@electricyachtssocal.com>;  
    Subject: RE: Westsail Rendezvous and Electric Yacht  
    Sent: Sat, Apr 19, 2014 5:50:57 PM  


    Thanks for the information.  Since I am not a member of the Westsail group, I cannot post on the website.   I am sending this to you if you would like post to the website for others.


    We have installed at least three Westsails. 

    ·         One is Mortens Westsail 32, a QuietTorque 20 with a DC genset to be installed later this year.   

    ·         Another was an H-Drive 8.0 diesel/electric hybrid installed in a Westsail 42 that left for Hawaii over a year ago.  I am sure he is doing well but have not kept up with his activity. 

    ·         A third H-Drive 8.0 was installed in February in San Diego in a Westsail 32.  Mike sailed off to Mexico the day after the install.  He was programing the settings with me over the phone while he was leaving San Diego harbor.


    The comments on power regeneration are correct.  The Westsail is impacted mostly by the size of the propeller, the fact that it is in an aperture and speed.  The Electric Yacht system gives the helm the ability to tune the regeneration of the boat to obtain the maximum amount of regeneration.  Even with that, it is speed of the boat and diameter of the propeller that influence the level of regeneration.


    After working with so many clients this is what I see as the advantage of electric for the Westsail.  One of the best features of electric propulsion is the ability to improve point of sail or increase the speed under full sail by up to 2kts.  This is accomplished with the application of the following. 

    ·         Apply almost no power to the prop, giving it about 100rpm, and the propeller disappears from the boat as it matches the speed of the water column.

    ·         Apply about 300watts (a modest battery bank is about 15000 watt hours) and you will increase speed by about 1kt.  Another 300watts you increase another .5kts.  This is not the traditional motor sailing but what one vendor calls “blended sailing”.  You are especially reducing the drag of the hull by removing some of the displacement drag as the boat is under full sail.  The Westsail sails as if it were several thousand pounds lighter.  You can share the “reduced drag” as an increase in speed of an improved point of sail.    I do this with my 11000lbs Columbia and am able to blend sail in many cases when others just motor.

    ·         With the diesel/electric hybrid, of which I am a proponent, you keep your diesel.  If your diesel is underpowered, you can support emergency operations by running both to drive the boat.  The smaller motor gives the heavy displacement Westsail harbor speeds and great slow control.  You can also put the electric into generator mode and it will provide from 1.2 to 4kW of power as a generator.  We have seen this system installed both at the transmission coupling (traditionally replacing the coupling) and also aft of the motor along the shaft at a convenient location in the engine compartment.

    In my opinion, today there are two proven companies that have systems that have the capacity to drive a Westsail, Elco and the Electric Yacht.  Both have pushed boats significantly larger and heavier than the Westsail 32s an 42s.  I see the electric as just a tool and if the sailor is looking for this type of tool it is a good solution.  It is not for everyone and it will not remove the need of a diesel from the Westsail as the diesel is needed to create power for the batteries.  

    When there are power storage systems that have the power density of liquid fuel, no one would consider anything but electric.  When that may happen is in the hands of the scientist and researchers. 

    Thanks, Mike

    Michael Gunning

    Director of Sales Electric Yacht

    Owner Electric Yachts of Southern California


    M 626 298 2262

    Toll free 855 339 2248 ext 109

  • June 27, 2015 7:55 PM
    Reply # 3407176 on 3403821
    Deleted user

    Some notes for Werner

    1.) all elec does not work if you want to motor (but is OK if you just use it to backout and enter the slip)

    2.) the series elec diesel ( elec motor with a generator to recharge bat's) is a bad choice. = just use more fuel!!! = bad ,bad, bad

    3.) the current parallels are not so great! but it is what is out there.

    some thoughts, and an inquire to Mike; to make a hybrid system cost effective you need the following; in my opinion

    a.) fewer parts

    b) better efficiency 

    c.) genset like op

    A grand Idea sprung to mind reading this question, and would consist of the following specs

    I.) Diesel engine eff improved by 3 to 15 % over conventional diesel engine drive designs (just by how the drive is done = no gears or clutches as we know them)

    II.) elec motor restricted to 5 to 10 KW bat cap. (less than most) with eff = straight elec systems. = back out and motor into slip via elec. and = bigger bat bank for house use and a built in gen set.

    III.) no clutches but could be (engine & elec to prop) (engine to prop) or (elec to prop) or engine to elec regen with no prop motion) with the reverse to prop from elec motor only.   

    IV) no transmission as we know it, No starter, no alternator, no clutch all replace by one drive part = less parts and just a little more than the cost of a bigger diesel engine. (true if the elec controller is not to much)

    This is a patentable Idea; so I can't share. but all of the above is not to hard and is possible, and I am amazed no one has done it yet, as it is dirt simple and very very Navy like.it is much like but not the same.


    But the shortfalls would be:  full power would be limited to an hour or so, then back to the diesel engine only. and you would need 2 to 4 8D bat's = a bit more weight, and lastly operation would be more effort unless done electronically.

    One footnote

    On Mikes notes; of added speed under low prop RPM, this is true (well I have seen it for myself) under low rpm engine while under sail speed increase was much more than the power input from the engine. So that part I can say is a positive for the current state of elec boat motors. 

    Last modified: June 27, 2015 10:21 PM | Deleted user
  • June 28, 2015 4:53 AM
    Reply # 3407621 on 3403821
    Deleted user

    Thank you all for your responses. The system I have in mind would definitely be a hybrid system. I am thinking a 10 to 15 KW motor at 48 volts. Charging from a single cylinder diesel driving a 100 to 150 amp 48 volt alternator as required. keeping the present fuel tanks at 70 gallons would give a theoretical range of over 1000 miles under electric drive alone, I believe. I need to be able to drive my present prop at 1700 to 1800 RPM using no more than 100 amps to make it feasible though otherwise might as well put Bud's Beta in there although the assisted sailing in itself is a great benefit. I can't get through a night watch without starting the engine for charging and have often seen a speed increase of 1 to 2 knots at 1000 RPM. Mocking this up in my shop is the first step to take so I'll be making an engine room out of foam to see how it all fits. I love to tinker with stuff and if Rhapsody wasn't her original name she'd be named McGyver.

    Keep it coming.



  • June 28, 2015 5:09 AM
    Reply # 3407628 on 3403821


    About 5 years ago, I read a news story about a startup company that wanted to build a starter/alternator/battery charger working off AC/7 kw. 115 vAC backup generator for your house.  It would be offered to the big 3 automakers.  Never made it to market.  I guess it was not as easy as they thought.

    Re the hybrid info from Mike.  A year ago, I sent Mike some follow-up questions.  He never replied.  Below are the questions I sent.

    I also have questions,  you say a modest battery bank is 15000 watt hours.  Wow!  How many batteries is that?

    A 6v golf cart battery we usually say has 200 amp-hour capacity, or 2400 watt hours at 12.3 volts.   It sounds like 6 such batteries to make 15000 wh.  Right?

    But the useful capacity is only about 25% of the nameplate rating.  Therefore, 3750 wh.  Drawing at 600 w means 5-6 hours on a full charge.  Is that right?  I'm trying to put  your electric drive in perspective.  Is this something for day sailors, or for long-distance ocean crossings?

    Solar panels:  I use the rule of thumb that on board panels can make about 250 watt hours per day per 100 watts of panel.  If the drive is used at 300 watts, 24 hours per day, then it would need 1500 watts of panels (5 hours per day) to keep up with it.  I know one W42 owner, Drake on Paragon, who has seventeen 100-watt panels.  With that many panels, and with 12 golf cart batteries, he could do it, but on a W32, I find room for 200 watts of panels max, and only two batteries. 

    I love the idea of using the drive as a generator to recharge the batteries using almost 75% of a 38 hp engine's available power to make more than 4 kw.   But 4.3 kw at 14 v means more than 300 amps of charging current.   What kind of wiring, what charge controller would one need for that?   Accidental or intermittent interruption of so much current could be a real safety problem.  I think an elaborate safety system would be needed.

  • June 28, 2015 5:17 AM
    Reply # 3407631 on 3403821
    Deleted user


    Thanks for your response and passing along the link to Mike's web site. To answer, I use the engine when I have to for leaving, arriving, charging and maintaining a speed of about 4 knots, which is my low target speed for passage making. Also, as Mike states in his email, the assist from "Old Thumper", as she is affectionately known, also allows me to point up a bit higher. On my last passage to Florida from Annapolis, I misjudged the tack around Cape Fear in SW winds and ended up pointed at Myrtle Beach instead of Georgetown. The engine allowed me to point up high enough to rectify my error and avoid another 60 mile tack.


    Last modified: June 28, 2015 5:19 AM | Deleted user
  • June 28, 2015 9:39 AM
    Reply # 3407736 on 3403821
    Deleted user
    Werner: Based on your comments (4kt min travel) the only option for you is Bud's bata! please see item #2 on my posting; you are proposing to do the worst possible solution = engine to gen 90%, gen to batteries 98%, batteries to elec motor 98% elec motor 95% or .9*.98*.98*.95 = 82% of what you would get from the engine buy itself. or about 20% more fuel usage. If you add solar you may get that number down to just 10% more fuel use.

    Dick: You are correct a great idea is very hard to get out there (mine has almost nothing to do with the electric gen/motor, nor much to do with the diesel but everything to do with the tranny.)

    a small math note: 300watts x 24hrs = 7200 watt hours not 1500 so your # of panels is 7200/250 = about 29ea 100 watt panels = wow that is allot. and if the elec motor is 98% eff (the best) the 300watt/745.699872 watt/hp *.98eff = 0.394 Hp or about the power of a cheap troling motor or about 1 kt in calm water. Dick I would like to thank you, for the comment on getting back to you, it helps in that, it is a comment on the company and will keep me from working with them. but for my design the bat would be 48Volt and the correct motor would be 26 to 28Hp knocking the amp's down 2.8Kw/48v = about 60 amps which is allot at 48v

    Werner just in case you still like elec motors (please try a project I did not do but wanted to do) a troling motor at the bow (could swing down from the sprit with switches for fwd off rev in the cockpit and have the motor mounted at 90Degs to the boat) which would make a great bow thruster and if aligned with the boat, a way to back out of the slip or up to the anchor. would be cheap, and along your idea. so 20% more fuel (per work hp but there would not be to many 600watts * 15 min = 150 watt hours = 1 panel) would get you better boat handeling in the harbor and not much cost .est less than 1k for the whole elec setup.(troling motor long shaft, battery and one solar panel) labor may be an extra 1k if you do not do it yourself. P.s. I would make it so the battery could be moved up to the motor but stored aft with the panel when not in use. (wire loss thing)
    lastly for regen from the prop please search this site and reread Mike's note: I don't think it can happen, Unless you are in a storm and surfing above 7kts
    Last modified: June 28, 2015 10:16 AM | Deleted user
  • June 29, 2015 4:36 AM
    Reply # 3408351 on 3403821
    Deleted user


    Thanks for your response. I see what you are thinking with item 2 regarding loss of efficiency and fuel usage. What I propose to cobble together for testing is a 20 to 25 Kw motor, a battery bank of eight 6 volt batteries for 48 volts and 200AH and a 1 cylinder diesel driving a 48 volt alternator for charging as required. The ship's 12 volt system would be run by stepping down the 48 volts to 12 volts to avoid having both a 48 volt and 12 volt bank. Solar would not be a player here as I agree there isn't enough real estate on a W32 to make it work except maybe to run a small 12 volt system as a backup for essential instruments i.e. VHF and navigation.  Also, I agree with you that the regen capability of these systems is very much overrated and 7 knots is probably about right to make it work.

    I've also had correspondence from Bud suggesting Mike's hybrid sail drive utilizing a 1 or 2 cylinder Beta which merits further research.

     My original Volvo MD11C is running just fine and at my age, may even outlast me or at least my physical capabilities. ( Dick and Libby, you are my continuing inspiration). My primary motivation for hybrid drive is keeping noise to a minimum so silencing a 95db diesel generator may defeat that entirely. I think the biggest challenge here is testing the system without committing to the removal of my present engine. What got me started on this was seeing a demonstration at a San Diego boat show last week. There was a setup from ePower utilizing a Thoosa motor and Lithium batteries. The numbers on the ammeter were really impressive but the prop was spinning in air.



    Last modified: June 29, 2015 4:38 AM | Deleted user
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