electric & inboard install design info sources

Discussion in 'Boatbuilding' started by Eric770, Jan 20, 2013.

  1. Eric770
    Joined: Feb 2011
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    Location: Hudson Valley NY

    Eric770 Junior Member

    I'm building an Atkins design, "Surprise", a 19 foot motor-sailer with an inboard motor. The basic hull is done and turned right side up. I'm looking for a good source for information to help me design the electrical, steering, motor, drive system, etc. It is a small, simple boat, but I'd like it to be safe and reliable. I've read references to ABYC standards, but they are very expensive for a one-off amateur project. Perhaps someone could recommend book(s) or websites that would help?
     
  2. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I own a much larger version of this hull form and it is efficient, but an electric propulsion unit, will easily exceed recommend weight requirements for Surprise. Reasonable performance can be had with an 8 HP engine, which will get you to about 15 MPH. To get this level of performance from an electric setup, you'll need a 10 - 12 KW motor, which isn't a small, nor light thing, compared to an outboard (for example). This hull shape will max out in the low 20 MPH range, which nothing short of an atomic reactor being able to push her faster. Any thing close to this speed will require a lot more the 8 HP. In fact to just get to 20 MPH, you'll need about 3 times as many HP as 15 MPH. Yeah, it sucks, but a reality of the boating thing.

    Price up a 10 - 12 KW motor and see where things shake out. Of course you'll need batteries (lots of them) which is what kills all hopes of economical and light weight cruising in electric. You have 300 pounds to play with, so the motor, controller and batteries need to be under this to give satisfactory performance.

    If it was me building that boat, I'd lose the midship engine box and mount a 10 - 15 HP outboard in a well, just aft of the box keel. You could put it under an aft deck and this would open up the whole cockpit area. If you insist on an inboard (why), then there are quite a few small gas and diesel engines to look at, Kubota is popular. Electric is a crap shoot. If you don't have a need for range, then just a few batteries and a motor is all you need. You'll get an hour of operation, before you've sucked them down and they should be recharged. On the other hand, if you want to putter around all afternoon, you just don't have the capacity for batteries in that boat, for a 10 KW motor.
     
  3. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    My electric boat links got lost after a computer repair . A good source for electric boat info are the electric boat clubs and forums. In North America and Europe. Because of pollution regulations electric boats are very popular in northern Europe. These are the only three links I remember.

    Do some googling. "Electric Launch" . One site I recall, a forum , in the Netherlands was exceptionally informative.

    http://www.ev-info.com/en/electric-boats-manufacturers.html?limitstart37=50

    http://www.electric-boat-association.org.uk/history.htm


    http://www.smartgauge.co.uk/batt_con.html
     
  4. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Again, compare weights and cost, for equivalent outboards. Lastly, compare range. You'll find if you pare things down enough to save weight, you have zip, for range. On the boat you're looking at, 1,000 pounds of motor, battery and controls would be a reasonable expectation, with a 4 hour range. This is nearly 3 times the recommended propulsion weight for Surprise. On the other hand, a gas 9.9 outboard in a well, could carry 25 gallons of fuel and still be well under the weight limit. Assuming a fuel consumption of 2 gallons per hour, you'll putter along for 12.5 hours, before needing more go juice.
     
  5. Eric770
    Joined: Feb 2011
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    Location: Hudson Valley NY

    Eric770 Junior Member

    Hey, thanks for the reply. I guess I should have been more clear. I'm looking for info on electrical systems, not electric drives. As well as designs for mechanical systems such as water cooling, exhaust designs, steering, that sort of thing. I in fact have a great Kohler, 30 hp water cooled, fuel injected, new, only weights 112 lbs. I have read articles that refer to Coast Guard specs, and best practices. I need a source for such information that will provide examples, rules, specifications that I can use to guide my design.
    Any ideas?
     

  6. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Gas or diesel? What type of electrical system? 12 VDC, 120 VAC? Electrical systems are designed around load, so what do you want aboard?
     
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