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Thread: Chines

  1. #1
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    Default Chines

    Are chines a fashion statement or the shape of boats to come ?

    What are the advantages and disadvantages ?

    paul

  2. #2
    boguing is offline Registered User
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    If the boat from which they cause aesthetic displeasure might surf or even plane, then maybe a good idea.

    If not, then a fashion statement.

    Having seriously played with patrol boat hull forms in a towing tank, I can tell you that spray rails are equally effective. Do bear in mind that we ran the patrol boats at zero heel, and then ask how a designer can guarantee the heel angle at which a chine will deliver flow separation.

    You already knew that though.

  3. #3
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    I think chines are primarily used in metal boats to enable the hull to be manufactured in either flat plates or in single curvature pieces. Rolling a double curvature onto a sheet is time consuming and expensive and has to be test fitted until it is right. A boat with chines the plates can simply be bent to shape around the structure and welded on.

    I guess it also applies to plywood boats.

    Ross

  4. #4
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    I was referring to the trend of seeing chines on racing and cruiser/racer sailing boats.

    paul

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    Claims to increase form stability and provide more area to enourage flat downwind performance. May well have an influence on reducing griping of rudders when wide bummed boats heel. Been used for some time on Thomas designed boats, but caught on recently with some of the big builders in an attempt to improve handling of lighter displacement wide flat bottomed boats. Time will tell if it is a fad or real advance.

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    Quote Originally Posted by paulburn View Post
    Are chines a fashion statement or the shape of boats to come ?

    What are the advantages and disadvantages ?

    paul
    I assume you are talking about chines on the quarters of modern round-bilge AWBs, as first seen in cruising boats in smaller British Hunters.

    Like the ancient Westerly bow knuckle, first seen on the Centaur, chines aft give a smidgeon more volume inside to use for accommodation. I suspect that making the aft cabin berths less tapered and slightly bigger is a major reason for the trend.

    There is also the fact - well known to car makers, that ridges in curved surfaces stiffen the structure, and allow you to get away with slightly less materials for the same overall stiffness. Production boatbuilders are currently working VERY hard to reduce costs and still turn out shiny saleable boxes.

    Finally, they may just improve heeled handling in some boats.

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    I used to own a plywood YW People's Boat (sounds very socialist, don't it?) when I was in Hong Kong. She sailed very well and I liked her so much that I seriously considered shipping her back to the UK but it would have cost too much. I bought the plans with the intention of building one here but never did. I disposed of them to someone on this forum a couple of years ago so hopefully he has built one.

    The Americans seem to like them (sharpies, they call them). Some of the designs are quite attractive (see books by Howard Chappelle). I suppose there would be more if it hadn't been for the invention of GRP yachts.
    'The lyf so short
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  8. #8
    oldsaltoz is offline Registered User
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    Quote Originally Posted by paulburn View Post
    I was referring to the trend of seeing chines on racing and cruiser/racer sailing boats.

    paul
    I'm pretty sure the return of chines is all about cost saving.

    No mold required, so less set up cost, no mold cleaning and polishing after each hull turn out.

    Easy to modify length and width with minimum fuss and low cost.

    Speed of production.

    And the list goes on.

    Good luck and fair winds.
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  9. #9
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    Gordonmc is offline Registered User
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    Quote Originally Posted by oldsaltoz View Post
    I'm pretty sure the return of chines is all about cost saving.

    No mold required, so less set up cost, no mold cleaning and polishing after each hull turn out.

    Easy to modify length and width with minimum fuss and low cost.

    Speed of production.

    I don't believe it is down to cost.
    My previous boat, a Hillyard 8-Ton had hard chines - it is carvel, mahogany on oak construction and I cannot see how the hull design would have presented a saving over a wine-glass contour.
    More likely the first owner specified he wanted a flatter shoal draft profile below the water-line for bilge plates with the additional gain of more internal useable space.
    The Golden Hind has a similar profile and so (I think) does the Eventide.
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  10. #10
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    I also think it isn't cost savings, because they are still laid up in molds.

    I believe that on race boats the theory is that that - particularly reaching - the boat leans over to a certain angle, then sits on the chine, presenting a flat surface that encourages planing.



    Last edited by bbg; 25-04-12 at 10:00.
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