The limits of soft covering materials - canvass??

Discussion in 'Boatbuilding' started by MarkC, Sep 25, 2005.

  1. MarkC
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    MarkC Senior Member

    I am wondering what 'hard' parts of a boat can be replaced by 'soft coverings' - what is the limit of the cloths? How much punnishment can treated canvass / sunbrella / pvc cloth etc take?

    I know about its use in folding-kyaks - I was more interested in boats/yachts.

    I starting thinking this after reading Ian Nicholson in his book 'small steel craft' suggesting in one chapter that hard parts could be replaced with cloth. He suggests the weight-savings (especially for steel boats) could be substantial, for example;

    "The essence of the scheme is that instead of using steel plating (or wood) for the aft end of the wheel-house, a Terylene, PVC or canvas curtain is substituted. Weight-saving is dramatic, because the curtain will be of the order of one-fiftieth of the steel weight".

    Ok - a wheel-house, dodgers (of course) - but what about other parts like - a cabin-house-top (probably not to be walked on) or the whole cabin house itself? What about parts of the deck? After-deck? Cockpit seats? Zip-door instead of wash-boards?

    I wonder what the tear-strength of the heaviest cloth would be? - UV issues asside.

    For attaching, I can imagine that bolts would have to be used instead of clips. Ian Nicholson recommends bolts at 4 inch intervals. Or is there another fastening method?

    For interiors, I have seen toilet, pantry and cupboard doors being replaced by canvass with strong attachments and heavy-duty zips for entry access - seems very successful.

    Clearly maintenance issues are important - perhaps they would have to be replaced every five years or so when subject to the elements.

    With today's modern cloths, why can't this work?
     
  2. MarkC
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    MarkC Senior Member

    Here is a canvass-fan! - (Mattotoole) talking about a canvass dodger.


     
  3. yipster
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    yipster designer

    i'm a -if well done- canvas fan but dont go bananas with it
     
  4. Bergalia
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    Bergalia Senior Member

    The limits of soft covering material

    From your address, Yipster, I assume you'd be sailing in not infrequently heavy seas - so I suggest any area prone to wash would be out. This leaves virtually only partitions and fitting below deck - so other than a saving in weight I can't really see a point of it. Unless you have only inland water ways in mind - then sure - any area not subject to heavy boots would be fine.
    For maintenance on the old canvas sails used on Scots' working boats (canvas weight 1lb per square yard - about 5mm thick) we used an annual dressing of fish oil and red lead. Dirty and stinky - but rot proof. But the canvas needed changing at most only at ten year intervals. (It then became overalls for the crew...)
    Sorry I can't be more help. How about a specific idea of the craft you have in mind, then we can all work on it. :rolleyes:
     
  5. yipster
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    yipster designer

    [​IMG] ah, were talking different sorts of "canvas" i'm talking luxory bimini's and the like. here a pic of a canvas i had made many years ago giving more space than the factory sunbrella with ysing glas windows that after 17 years is still good while this bigger custom tent windows cracked out and the canvas deteriorated after only 2 summers. also got a tonneau cover and a winter canvas and am tossing with the idea -canvas is expensive also- making a new summer canvas like in the pic. now i want to leave out the rear bar by maybe putting the radar arch back a bit or turn it around so the bar hinges in, make sliding rails in the arch to mount the canvas like on new boats, got an industry sawing machine and plan diy this time couse having a tent like this made easely sets you back 3k. so nothing but good about sunbrella but never wash it like i did or it srinks lengtwise and gets wider over the beam. i dont care much for canvas ventilation story's that it has te be cotton, so i'm looking into lightweight poly textiles now that lets light in, fold away easy and live forever. there is a a lot more to be said bout canvas, like forexample i saw solarcells that roll up, wouldnt that be nice to integrate etc.

    did some motoring on the north sea ( and med ) but boats berth is on the big inland lake now. for sailboats a small canvas cover can do miracles also in rough wheater and with a little style in them they look good also. now for real canvas 5 mm thick thats another story i guess...

    attached a bimini diy txt
     

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  6. Bergalia
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    Bergalia Senior Member

    The limits of soft covering materials - canvass ?

    I see the problem clearly now Yipster. Not what I had in mind. Sorry. Only material I can think of is that stuff they use on tonneau covers for sports cars. Expensive though, I should think. But might be worth exploring vintage car restoration people. But no doubt wiser fingers are already tapping the keys. Good luck my friend. :cool:
     

  7. MarkC
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    MarkC Senior Member

    Thanks for the replys so far.

    Dodgers and dog-houses are good, but I was suggesting actually replacing sections with soft coverings.

    For an example, what about this very nice steel motor-cruiser by Ganley:

    [​IMG]

    [​IMG]

    What if I substituted the all steel/wood dog-house/steering cabin - with a permanent frame and canvass-top and sides?

    To go even further - what about the entire cabin (the sides and the roof) with some way of openning the cabin-sides for ventilation. Plastic windows or maybe a permanent windshield. OK - the mast is in a steel collar, the lines and winches are all set-up etc.

    Could the covering be as strong as wood??

    Here is a nice steel John Pugh 32 - with a large cabin where it could work.

    [​IMG]

    I was thinking of the weight-savings primarily. Ventilation issues too.

    Yes 'wash-zone', breaking waves, heavy boots and knives and the cold are important - but a mega-tough modern treated canvass, PVC or other cloth - properly attached with bolts - perhaps painted with a top acrylic etc. could work? All run past a NA - yacht designer of course.
     

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    Last edited: Sep 27, 2005
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