Any well insulated boats on the market? 23ft - 30ft

Discussion in 'Boat Design' started by Wellington, Jun 27, 2018.

  1. Wellington
    Joined: Jun 2018
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    Wellington Junior Member

    Does anyone know of any boat brands from scandinavia which are known to be heavily insulated for cold weather conditions? I am also on the look out for a motor sailer with 6ft headroom and a good wide beam and canoe stern in the same length range. Any Suggestions?
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    I suppose this is where GRP sandwich construction shows one of its advantages, but how effective 12-15mm of foam is in insulating a hull in frigid waters, is probably doubtful.
  3. Wellington
    Joined: Jun 2018
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    Wellington Junior Member

    Thanks. Ill take a look at foam sandwich boats. regards
  4. Tiny Turnip
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    Tiny Turnip Senior Member

    My understanding is that with boats as compared with buildings, any insulation tends to be relatively thin, so as not to eat into cabin space, and is there to provide resistance to condensation (less cold interior surfaces to the cabin skin) rather than a serious attempt to reduce heat loss.

    Mr E makes good points.

    I suspect that most heat loss will be not be conducted through the cabin skin, but lost through ventilation, and the pretty constant movement in and out of the companion way.

    Fuelling a heater will be a very small fraction of the overall costs of running a boat.

    The cheapest and most effective place to put insulation is next to your skin. I'm a fan of buffalo systems clothing and sleeping bags, but its fair to say I do enjoy my sailing a bit rough round the edges...
  5. HJS
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    HJS Member

    Why a canoe stern? What's the benefit on a motor sailer?

  6. Wellington
    Joined: Jun 2018
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    Wellington Junior Member

    Yep, that would make sense. had not thought of it from that angle. Thanks for the useful practical tips. kind regards
  7. Niclas Vestman
    Joined: Aug 2017
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    Location: Malmoe, Sweden

    Niclas Vestman Senior Member

    Interesting questions. I'm Scandinavian, and I get your point on good insulation. I made a quick calculation and came to the conclusion that good insulation matters. Although, after some investigation, it doesn't make sense to make a sandwich core thick enough to handle all insulation needs. A hull about 27' would have at least 10mm. Insulation rating (lambda) for foam is about 3W per m2 hull area, and per 10mm thickness and per degre temperature difference. For about 35m2 cabin area and 10 deg C outside temp, 22 deg inside temp, a 10mm foam sandwich would loose 3W*35m2*12dT=1260W continous, or about 30kWh/24h. Adding 10mm foam as interior lining would cut that in half. That should equate to about 5L or 2,5L in a diesel heater. In ideally controlled ventilation, an absolute minimum is 5L/second/person. But to avoid moisture 10L/s/p would be better. In reality opening hatches, and wind sucking out air would probably add substantially to the air exchange. Using 15L/s/p, 1,296W to heat 1L air/deg. Resulting in 15*1,296*12=233W continously or about 5,6kWh/24h. That's less than 1/5th per person compared to a 10mm sandwich hull radiation heatloss. If living on a boat, at least in periods, I'd opt for 10+10mm insulation, and maybe a simple DIY heat exchanger, and probably a wallas or similar heater. In moderate cold climate, no winter use, a solar heater, and the roughly 100W continous body heat per person, might render a heater superficial.

  8. Wellington
    Joined: Jun 2018
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    Wellington Junior Member

    Well you sure did your sums. But im hoping living on a small boat wont be a constant battle shifting between too hot and too cold. i'm told it is very difficult to regulate heat in small spaces so i guess dealing with condensation will be quite a big issue. i like the look of the refleks drip heaters. they seem like a god solution. thanks for the detailed math.
    Niclas Vestman likes this.
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