Dinghy winter storage

Discussion in 'Boat Design' started by laukejas, Sep 26, 2015.

  1. Stumble
    Joined: Oct 2008
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    Stumble Senior Member

    So long as it's an incandescent light. Putting an LED isn't going to help much.

    The other option is a heat wand like http://www.cabelas.com/product/GOLD...=GoogleProductAds&WT.z_mc_id1=03823154&rid=20 they just warm the space a little, but the localized heat makes all the difference. I still think better ventilation would be the best option if you can manage it.

    Something like http://www.homedepot.com/p/Active-V...whEdh1JAhOuDE5_qM1VMLxoC_4vw_wcB&gclsrc=aw.ds will drop the humidity in the entire garage to match the outside.
     
  2. Petros
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    Petros Senior Member

    you have to check the electrify rates in your area, but it should not be much. yes, it is worth it, many do it with their larger trailer sailors here because of the cost of cleaning up mold and mildew inside a cabin. a larger 60 watt or higher would work even better, but also cost more. the wattage determines how much heat output (convert electricity into energy, both heat and light). The light will also resist some types of mold that grow in the dark.

    You do not need to really heat the whole garage, just get the area around the boat warmer than the rest of the garage. the slightly higher heat will drive the moisture away from the boat, you will have extra dry air in the boat since the partial vapor pressure will drop with just a few deg rise in temp around the boat, making the air extra dry. the light under an up turned boat hull, with perhaps even a tarp draped over it, will hold enough heat in it to keep mildew away.
     
  3. fredrosse
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    fredrosse USACE Steam

    Heat Source

    As Petros says, it is the watt rating of the light bulb that matters, 40 or 60 watts will provide moderate heat for an upturned hull in a space that has no wind air circulation.

    Heat from the bulb rises, so place the bulb about 30cm below the keel, slightly warm heated air will rise up into the overturned hull, filling it with air at a slightly higher temperature than the surroundings. Any significant wind circulation around the hull would probably wash away any heated air from such a small energy source.
     
  4. laukejas
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    laukejas Senior Member

    Hello again,

    I'm sorry I'm reviving this old thread that I started a while ago, but I need a little help again. As you good folk have advised me, I have suspended my beloved boat upside down in that garage on sawhorses, then hooked a 40 watt bulb underneath the hull (inside cockpit), and left her like that for the winter.

    Now that the snow has melted away (it might return yet), I have came to inspect the boat. During these months, the temperatures in the garage were always near or below freezing point. It turns out that garage has excellent natural ventilation: walls are planked, with many gaps, and you can feel the wind circulating inside, while the roof does not let the rain in. Sounds ideal? Only that it isn't. Despite ventilation and the light bulb, moisture levels are unbelievably high. When I came to inspect it last weekend, temperatures were just barely above freezing point, and every rag in that garage was soaking wet, the concrete floor was wet. And my boat has developed serious mildew:

    [​IMG]

    (Yes, these grey spots are mildew, it has covered almost the entire boat - and before storing for winter, I scrubbed her until she was shinning white).

    It appears that the light bulb trick didn't work. Fortunately, the mildew didn't set in deep - it can still be cleaned away when scrubbing hard, so it hasn't penetrated the paint (yet).

    However, it seems that even in freezing-point temperatures, moisture can make a lot of damage to my boat. I want to make sure this never happens again. I have absolutely no other place to store the boat in. Heating that garage throughout the winter or installing a serious dehumidifier is completely out of the question in terms of finances (I can barely afford to heat my own flat). What should I do? Right now, that garage is damp like a cellar, and clearly, no ventilation can help it. Why does mildew occur in such low temperatures, and what can I do to protect my boat from the moisture?
     
  5. Jamie Kennedy
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    Jamie Kennedy Senior Member

    Nice looking boat. I am surprised by the moisture as I thought you would have a very cold dry winter there. Can you store it on it's side up against a wall? That can be a very good way to store some boats, resting on their gunnel, on some wood strapping. I am guessing the garage is damp because it is getting some heat from the house and melting snow from the outside. The freeze-thaw cycles can be troublesome. It would almost be better outside the garage, on its side against the wall but under the eaves. So it would freeze, but by dry, and not suffer so many freeze thaw cycles.

    Another good option is suspended from the ceiling, of your garage, or living room. :)
     
  6. laukejas
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    laukejas Senior Member

    Well, that house was empty and not heated throughout the whole winter. So except for that little bulb, there was no heating anywhere nearby - the only freeze-thaw cycles could come from natural changes in weather...
    There's very little space in the garage to store the boat in the way you described (walls are already occupied with other stuff), but even if it's possible, would it make a lot of difference?

    As for storing outside, there were several rags left out in the porch of that house (outside, but below a roof), and even though they were protected from rain and snow, they were damp too when I arrived. It seems that despite the cold, our weather is very damp.
     
  7. Jamie Kennedy
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    Jamie Kennedy Senior Member

    You could try a tarp over the boat, pitched like a tent, just off the boat, and store the boat right side up, with two bulbs inside the cockpit under the tarp. Just enough heat to keep the air circulating and maybe enough light to stop the mildew. You can also keep working on it through the winter. Keep an eye on things. Any excuse to get away and have a few beer right? Dream of summer.


    Charles G. D. Roberts (1860-1943)

    In an Old Barn

    Tons upon tons the brown-green fragrant hay
    O'erbrims the mows beyond the time-warped eaves,
    Up to the rafters where the spider weaves,
    Though few flies wander his secluded way.
    Through a high chink one lonely golden ray,
    Wherein the dust is dancing, slants unstirred.
    In the dry hush some rustlings light are heard,
    Of winter-hidden mice at furtive play.

    Far down, the cattle in their shadowed stalls,
    Nose-deep in clover fodder's meadowy scent,
    Forget the snows that whelm their pasture streams,
    The frost that bites the world beyond their walls.
    Warm housed, they dream of summer, well content
    In day-long contemplation of their dreams.
     
  8. rasorinc
    Joined: Nov 2007
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    rasorinc Senior Member

    I think the least expensive would be to cover the bottom with old blankets or carpet
    and then a moisture proof cover over that. Leave loose on the sides and bottom just hang it there. Then increase the light bulb to an 80 watt or even a 100.
    I wonder if a heavy wax coating on the bottom would help with the mold????? You can clean it off with a hair dryer on high. What is the size of your boat?
     
  9. SaugatuckWB
    Joined: Jan 2014
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    SaugatuckWB Junior Member

    Winter Storage

    It sounds like you have created a warm (relatively) moist environment by 1. storing the boat upside down, and 2. heating it. Moisture is probably coming through the concrete floor and the warmth from the bulb is trapping the moist and warm air in the overturned hull.

    So the solution is to cover as much of the floor as possible with plastic sheeting to create a vapor barrier. It will be wet under the plastic but who cares. Then turn the boat right side up, clean it with bleach water, and cover it with a breathable tarp (canvas or worn out poly tarp) just to keep out dust, etc. Get rid of the light bulb as lower temps will retard mold growth.

    That's typical cold weather storage.
     
  10. Heimfried
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    Heimfried Senior Member

    That is really difficult to say without looking at your garage and measure the conditions. The advice to turn your boat und "heat" it with a bulb was correct and is normally helpful.

    To develop mold at a surface three requirements are needed: 1st: mold spores (are nearly everywere in the air), 2nd: an "activity of water" (German: Wasseraktivität) at the surface of 0.8 (or more) for some weeks (or longer) and 3rd "food" (nutrient medium). Low temperature slows down the development of mold but does not prevent it.

    An activity of water of 0.8 or more is given, if the relative humidity (RH) of the air of the boundary layer at the surface ist 80 % or more. (It depends strongly on the temperature of the surface and there is normally a difference to the RH of the room air!)

    For example: the air temperature in the garage is -4 °C and the RH is 95%. If the bulb would warm up the hull to -1 °C, the RH of the boundary layer would be about 74 % and your boat would be safe.

    But if the natural ventilation in your garage blows most of the the warm air (produced by the bulb) just away, it cannot warm up the hull. So if the temperature of the hull would be -3 °C the RH is 87 % and mold will occure.

    Next point: you scrubbed yout boat before storing, normally the nutrient medium should be gone then. Is it possible, that the hull paint provides nutritive substances so as organic compounds? (Maybe also the invisible rest of alga after scrubbing is enought; mold is modest.)
     
  11. laukejas
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    laukejas Senior Member

    So, do I set up a stronger bulb, or do I remove it altogether? :D I really don't understand this. Do I want low temperature, or do I want to heat the boat up? In any case, I'll try to store her vertically.

    Thank you for that fairly scientific information. I'm still a bit confused. You said that low temperature slows down mold growth. So why is it bad that natural ventilation blows away warmer air produced by the bulb?

    In any case, temperatures sway wildly during non-sailing season. The season ends at September/October, and starts again in June. Between these months, temperatures are normally between -30° and 15° Celcius, and it's not uncommon for them to fluctuate in 20 degree range in a matter of days. So it's impossible to predict what it will be like. In any case, bulb can make only a degree or two of difference.

    You see, I live in a city center, and my boat is stored on the outskirts of the city, in a wooden village house garage owned by my grandmother. That house is 20 miles away. During winter, the house is empty and not heated. The whole village is a bit swampy, so moisture levels are always high. So for me, it's pretty much "leave boat there in October, collect it in June", with only a few checks in between.

    Anyway, I'm sorry for my slow brain, but again, do I want to raise the temperature with the bulb, or instead, keep boat as cool as possible? As I said, temperatures range from -30 to 15 C during "storing season", and there is nothing I can do about it.

    P.S. You asked if the paint itself can give mildew the nutriets it needs. I used 1 part urethane alkyd enamel for outside of the boat, and typical acrylic house paint for the inside. The mildew is most noticeable on the inside, on the acrylic paint - but then again, it is white, while outside of the hull is blue, so maybe mildew is everywhere, just more difficult to spot on the blue.
     
  12. Heimfried
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    Heimfried Senior Member

    Do you like mold more, if it is grown slowly?

    Goal should be, to prevent it, right?

    If you are able to achieve a temperature of the boat hull, which is about 4 °C above the air temperature in the garage, your boat ist most likely sure, because the RH in the boundary layer is less than 80 %, even if the RH in the garage is 100 %.

    Maybe a temperature difference of 3 °C is also sufficient.
    If the boat is only 1 °C warmer, the bulb will not help at all.
     
  13. laukejas
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    laukejas Senior Member

    I see. So it's all about temperature difference, right? So, installing more and/or powerful bulbs will help?
     
  14. Heimfried
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    Heimfried Senior Member

    If I remember right, some sort of mold like to "eat" some house paints.
     

  15. Heimfried
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    Heimfried Senior Member

    Yes, but think about danger of fire.

    (If you are able to deal with a bit German, you can calculate about air temperature and humidity here: http://www.hygrothermik.de/rechner/lueftungsrechner2n.php
     
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