reverse sheer

Discussion in 'Sailboats' started by tshino, Aug 29, 2009.

  1. tshino
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    tshino Junior Member

    I am looking to trace the origin and evolution of reverse or positive sheer in sailboat design. The earliest example I am aware of is Buttercup, 1937, designed by Robert Clark. I have not seen drawings of Lord Riverdale's 1st Bluebird and wonder if that is precedent, and if not, what was? Can anyone shed light on this?
     
  2. Gary Baigent
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    Gary Baigent Senior Member

    Some of the earliest would be the fast sailing Sneakboxes (based on low wooded waterfowl gunboats, hence the higher midsections) from the US in the 1830's. These were foreunners of Sandbaggers - although the latter were not reverse sheer. Manfred Curry designed a reverse sheer, lightweight, big planing dinghy in mid 1930's??. Howard I Chapelle designed a bloody fast 22 foot racing sloop centreboarder a bit later. There's one here on the Waitemata. If you look at some ancient North American canoes, Micmac and Chaleur Bay, both designs sometimes sailed, the Chaleur Bay are sea going designs and these two had pronounced reverse sheer - and you're talking centuries back here. Kodiak Island kayaks also had reverse sheer - now you're going back many hundreds of years.
     
  3. tshino
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    tshino Junior Member

    thanks for that Gary...

    I am looking at a kayak design of the Netsilik, a caribou hunting weapon from central arctic Canada, collected in 1913, and it too has reverse sheer. I am asking more about how this idea entered western design thinking in the early 20th C. Duckboats are an interesting line of inquiry. Thanks.
     
  4. Ramona
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    Ramona Senior Member

    I think with small yachts around 22 feet its hard to have a good looking sheerline and retain some interior room. May as well have reverse sheer and pick up more room. Tasman 22 was a good example in Australia in the 1960's.
     
  5. ancient kayaker
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    ancient kayaker aka Terry Haines

    If you look at a sailing monohull with conventional sheer as it heels, water is lapping at the midships sheerline except where the hull wave drops. Even with flat sheer same thing happens. So reverse sheer, while not pleasing the the normal sailor's eye, makes a lot of sense by raising the sheer at midships.

    Typically such boats are low at the stem and stern; I would think that would make for a wet boat that can also get pooped easier than most, but would cut down hull windage which should improve leeway and speed. A cabin and high coaming does the same thing more comfortably but less efficiently.

    As a kayaker I am sensitive to the effect of the wind on the hull; it can make it hard work to maintain course even downwind on some boats.
     
  6. Paul B

    Paul B Previous Member


    I'm not sure what a normal sailor is, but I like a well drawn hogged sheerline.

    Carl Schumacher used it on his Express 27, and John Reichel used it on his Melges 32. Both look great.
     

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  7. jmolan
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    jmolan Junior Member

    I believe the Searunners all have reverse sheer. In addition they have camber side to side. Water NEVER collects on the deck of these boats. It is pretty hard to get water on deck to start with...:)
     

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  8. ancient kayaker
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    ancient kayaker aka Terry Haines

    Those look to have considerable freeboard which would tend to make them dry boats. reverse sheer looks OK to me, logical thing to do, but I don't see the point on a cat. Must be other factors I am not seeing. Like Ramona said, it also adds to interior space.
     
  9. jmolan
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    jmolan Junior Member

    yes, freeboard helps to keep er' dry. Not having a big chunk of lead strapped to the bottom of the boat helps too! :D
     
  10. booster
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    booster Senior Member

    Ljungström

    The reversed sheer by Ljungström shall not be forgotten. His innovative rig is interesting as well.
    Regards,
    Booster
     
  11. Tanton
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    Tanton Senior Member

    Reverse sheer.

    Not to be forgotten, the reverse sheers adopted on many Illingworth and Primerose designs. Blue Charm; Dambuster. Outlaw; Midnight etc.
     
  12. booster
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    booster Senior Member

    Fredrik Ljungström, 1875 - 1964

    Hi!
    Yes, Tanton several designers have done the sheer and shall not be forgotten.
    Regards,
    Booster

    fredrikljung.jpg

    ljungstrom.jpg
     
  13. messabout
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    messabout Senior Member

    Much hogwash has been spoken about the beauty of a boat with a lovely sheerline. Acknowledged wizards like Chapelle make a big deal of it. Conventional taste admires a lively sweep in the sheer. My question is this: how did we decide what is pretty and what is not? Is there something buried in our genetic code that demands that such and such a curve is attractive. (alright guys I am talking about boats not women)

    Much has been written about the golden ratio too. Somewhere around five eighths to one I am told. Supposed to be the magic proportion.

    Reverse sheers, for me, look kind of sexy and somehow suggest speed. My M20 scow had that look and I loved it. I also see plumb bows as a speed symbol, particularly if the boat is a speedy one, say like an International canoe or an Int14. On the other hand I see traditional Maine lobsterboats and Hamptons as objects for admiration. They have exaggerated sheers and towering bows. The Mainers have probably done that stuff as a matter of practical design for their area, not for aesthetics. But for the general public there is no accounting for taste is there.
     
  14. ancient kayaker
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    ancient kayaker aka Terry Haines

    Well, I'm no MA but if I had to design an open boat to survive at sea I wouldn't give it reverse sheer even if it were a sailboat. In a big sea I would either want to run before it or face into it, so the high bow and bouyant stern may save my life, if I have the understanding of it, and the low midships would be easier to climb back into, or ship oars, or fish or do a whole lot of things except present a large area for the wind to play with. But it wouldn't win races. I don't see it as a matter of esthetics either way, just giving a boat what it needs in order to do its job.

    I have designed and built several canoes. They evolved over time, now they all have higher stems than sterns so they don't weathercock in a crosswind, plumb stems so they cut through waves instead of rising over them which wastes energy, and minimum freeboard midships for easy paddling. It is just happenstance that everyone who comments on them likes their looks.

    I agree that designing for appearance for its own sake is pointless. or perhaps the point is salesmanship. But generally there is a balance to a well designed functional object, especially something like a boat that is all curves in order to do its job. The big exception being, of course, some of Phil Bolger's designs -but not all of them- but then he was in a class of his own.

    OK, so you weren't speaking of women Messabout, but you must have noticed that the better looking ones are usually also in good health.
     

  15. booster
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    booster Senior Member

    Reverse rocker

    Hi!
    Yes, reverse sheer is sometimes beautiful. However, it takes a lot of design-effort to make it beautiful. The ultimate goal for a boat-designer must be to make reverse rocker looking nice.
    Regards,
    Booster
     
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