Solar Canal Camper

Discussion in 'Boat Design' started by SolarCanal, Aug 9, 2017.

  1. SolarCanal
    Joined: Aug 2017
    Posts: 3
    Likes: 0, Points: 1
    Location: Sweden

    SolarCanal New Member

    I'm investigating the possibilities of building something like the Sienna 19 or Secret 33 from Scruffie Marine and use as a canal camper.

    The wish list includes
    • Monohull
    • 6-8 meters length and 2-2.5 meters width
    • 2-3 knot capabilities on solar only (some 6-10 m^2 of solar cells)
    • 5 knot cruising capabilities from battery pack (for "good part of the day")
    • Port charging capabilities
    • Sleeping accommodations for 2 adults and 2 children
    • Bathroom/Change room
    • Stove and sink
    I can accept bringing an outboard fossil fuel motor for emergency capabilities but would want the electric system to being able to handle crossing slightly windy lakes.

    From what I read over the last few days this seems possible, and the Sienna 19 and Secret 33 makes me believe it. What do you experts think?

    Since I know nothing about boatbuilding I wouldn't dream to think about building the hull myself so I am looking for suitable hulls. Now to my first question if you at all think this is possible; what hull should I be looking for? I have been looking at what I believe is called "double ender" hulls (Swedish name is Snipa) like this one
    snipa.jpg (length 6.7m, beam 2.3m, draught 0.7m, weight 1100kg)
     
  2. SolarCanal
    Joined: Aug 2017
    Posts: 3
    Likes: 0, Points: 1
    Location: Sweden

    SolarCanal New Member

    I read somewhere that wood hulls are lighter than plastic/fiberglass hulls. So would for example a traditional "planked" wood hull be lighter than a same size boat plastic/fiberglass hull or is this only true for plywood hulls?

    Also, is there some ratio that should be obeyed regarding hull weight vs everything else weight? I'm thinking center of gravity should be low of course but motor plus batteries will help keep it low.

    Should I be looking out for something special if I for example would want to fit a Torqueedo Fixed Pod as the motor?
     
  3. Rumars
    Joined: Mar 2013
    Posts: 100
    Likes: 12, Points: 18, Legacy Rep: 39
    Location: Germany

    Rumars Senior Member

    It's possible in theory. It will be expensive in practice. You need a long thin hull. L/B ratio should be as high as you can get. Plywood and cored fiberglass are usually lighter than traditional wood or solid fiberglass. For keeping weight down you need to go to lithium batteries. The solar panels can be thin semi-flexible ones. The problem is of course good quality ones are expensive and the chinese cheap ones do not last long.
    PM motors are also lighter.

    The point to start planing the boat is how much solar you need. For that you need to find out two things: how much energy solar panels produce on an average day on your cruising ground (information available usually from photovoltaic associations) and how much energy the boat takes for moving at 2-3kn under tipical conditions (will differ from boat to boat). Example: 10sqm of solar panels usually means around 1000Wp. In your location and with flat mounted panels they will produce only 500W. Can the boat achieve desired speed with 500W under tipical conditions?

    Electric canal cruisers have been done but they usually depend on battery power and recharge stations or generators. Solar is difficult, especially at higher latitudes and may require a cutsom designed and buildt boat.
    My advice: buy a displacement boat you like. Find out how much power you need for it under normal cruising conditions. Select a motor and controller. Cheapest way is to go with a used forklift motor and controller on the existing driveline. Go over to Norway and procure a lithium battery bank from a wrecked electric car. Rewire and fit BMS. Fit as much solar as you can and install a DC generator capable to recharge the batteries in a short time. Have a programable high power charger for using shore power.
     
  4. SolarCanal
    Joined: Aug 2017
    Posts: 3
    Likes: 0, Points: 1
    Location: Sweden

    SolarCanal New Member

    Thanks for your awesome write up Rumars. Hadn't thought of forklift motors and such at all, maybe even a golf cart motor (or two) could do. Now where to source such motors!

    A couple of followup questions on the hull part. I assume you mean that for any given length you would want to keep the width as narrow as possible to keep the L/B as high as possible, or is a boat 8m long and 2m wide a better choice than a boat 6m long a 2m wide even though the longer boat is heavier (given similar design)? Or are you thinking in the line available area for input power and propulsion requirements? Any idea what L/B ratio I should aim for? 3 - 4 - 5? Don't say 22 :)
     
  5. Rumars
    Joined: Mar 2013
    Posts: 100
    Likes: 12, Points: 18, Legacy Rep: 39
    Location: Germany

    Rumars Senior Member

    You asume right. The problem of course is that a narrow boat has less accomodation. A 8m long and 2m wide boat (L/B =4) would be better. Even better would be something even longer and still 2m wide. I don't think you can get much higher than 6 in a "normal" boat and even that can be hard to find.
    Power requirements are actually pretty low for canals. No current and usually sheltered from the wind by trees means even heavy boats can get away with low power, especially when going slow. The real problem is solar. With current technology we need between 6 and 10 sqm of panels for 1000Wp. The weight of the boat increases much more rapidly then the surface to mount panels, so there comes a point when solar is just for show. Basicly if two or three people can row the boat at your desired speed it's possible to use solar propulsion. Battery propulsion is something else and only depends on your budget. Second hand motors and controllers can be had from companies that sell and repair electric forklifts, floor sweeping machines and associated equippment. They also have low power motors wich usually power the auxiliary drives in forklifts or from sweeping machines. If you want new, there is a series of vendors in Europe where you can buy everything.
     

  6. rwatson
    Joined: Aug 2007
    Posts: 5,134
    Likes: 140, Points: 63, Legacy Rep: 1749
    Location: Tasmania,Australia

    rwatson Senior Member

    waikikin likes this.
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