e-motor sail-catamaran

Discussion in 'Propulsion' started by anton, Nov 21, 2010.

  1. anton
    Joined: Nov 2010
    Posts: 2
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    Location: Netherlands

    anton New Member

    Hi, i recently bought a James Wharran pahi 43' catamaran see

    Currently living in Holland but want to emigrate to Malaysia. There is loads of sun and that is what I want to use as energy supply together with wind energy.
    The catamaran is 16 years old and needs a major refit. I also want to make it a green boat. I am not much of a sailor so the sails need to go or I will only use them for long trips.

    I want to use these type of motors
    build inside the rudder.

    Loaded the boat will weigh 6000kg (for the sake of sanity lets stick to the metric system) but I don't need much speed 10km/hr cruise speed will do. There is 36m2 to install solar panels. The fridge and laptop will consume 100watt.

    I want to be able to cover a distance of 70km a day, that makes it 7hrs. If I use the 3500watt motors (2 one in each rudder) what would be the best solar panel option? And do I need additional batteries?

    I don't know if this is possible so any input is welcome.

  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    So, are you taking the rig off? Otherwise, 10km/hr (5.5kt) is a modest speed under sail.
  3. anton
    Joined: Nov 2010
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    Location: Netherlands

    anton New Member


    I am thinking about it, it is a hassle to operate and maintain

  4. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Assuming that 2 pod engines at 50% power will give you the target speed ( I cannot verify that of course), you need 3.5 kW input.

    36 m2 of solar panels will produce that power plus a little extra as long as the angle of incidence is 90 +/- 20 degrees, no clouds, the panels are clean and there are no shadows.
    Such a situation does not exist for 7 hours a day, so for this kind of project you need every bit of sunshine from sunrise till sunset if you want to cover the daily 70 km.

    That is where the problems start. You need storage batteries for any situation that deviates from the ideal one: 10 kW if you restrict you travels to reasonably sunny days, twice that if you want to be able to sail in the dark or on a heavy overcast day. To get an acceptable service life, you have the choice between expensive deep cycle batteries or twice the capacity with plain lead-acid batteries.

    Be prepared to invest 50.000 euro on panels, batteries, controllers, wiring etc. when you do the installation yourself.
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