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Thread: Sail types - and efficacy

  1. #1
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    Default Sail types - and efficacy

    Oppies with different sails



    And a comparison article.
    http://www.lukawskiyachts.com/mona/class.htm

  2. #2
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    On a sailing canoe; I prefer a bermudan with round mast reefing for simplicity, upwind performance, quick easy reefing on the water and therefore safety (due to the last item).

    On the river I sometimes use a lugsail - good for for sailing under bridges.

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    Fascinating !

  4. #4
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    The Crab Claw in the picture could be seen as a bermudan upside down. This puts the maximum area higher up. Wind is generally slightly stronger higher up so this rig will generate more force for a given wind strength. It also will generate larger overturning moments (ie capsizing forces) so as the wind gets stronger you would be at a disadvantage. For cruising ,away from a race rescue boat, the easy reefing ability of the bermudan and lower centre of effort
    wins every time.
    Also if you look at the race results over 2 races the variation could be a good indicator that it was skipper ability or luck that gave these results. 2 races would not give a significant result. There should be many races over different conditions with the skippers swapping boats to get a statistically more accurate result. Thought provoking though.
    Last edited by DaveS; 26th-September-2012 at 07:36 AM.

  5. #5
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    "Thought provoking" is about right.

    I've seen crab-claw(AKA oceanic lateen) sails rigged in a number of different ways - some of which produce a much lower centre of effort.

    They are a bit of a horror if you want to reef - the Mediterranean lateen takes an unexpected approach to this problem.

  6. #6
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    Speaking of sail types, here is an interesting video of a reproduction of a pirogue, built by an enthusiast here in Quebec, Canada. The sliding mast foot is interesting.

    http://www.youtube.com/watch?v=YQ-YF...ature=youtu.be

  7. #7
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    I never really understood the advantage of shunting a Crab Claw. (Sliding the base along the gunwale) It seems like a lot of work to sail back in the opposite direction whereas using a normal sailing rig, you would just put in a tack and turn the boat around. Perhaps as a river ferry it makes some sense I guess!

    I also don't like the way they reef. Nope not a big fan I'm sorry!

  8. #8
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    Quote Originally Posted by Steamerpoint View Post
    I never really understood the advantage of shunting a Crab Claw. (Sliding the base along the gunwale) It seems like a lot of work to sail back in the opposite direction whereas using a normal sailing rig, you would just put in a tack and turn the boat around. Perhaps as a river ferry it makes some sense I guess!

    I also don't like the way they reef. Nope not a big fan I'm sorry!
    the shunt is so the outriger is always on the windword side , and the reafing is similer to what uropeans yoused on sprit sails caled a braling line , it simply lifter the sail and sprit up and across to make room for loding cargo an to youse the sprit or boom as a loading gantry .
    why wold you wont sumthing so complicated on a canoe ? simpal is always best .

  9. #9
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    Quote Originally Posted by Steamerpoint View Post
    I never really understood the advantage of shunting a Crab Claw. .....
    The shunting business only begins to make sense once you have understood the hullform of the kiribati proa - these will do twenty knots - and can get to weather in under nine inches of water - subtle and very very clever.

  10. #10
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    Thanks Doug & Mick. So they essentially sail better with the outrigger upwind and therefore really need to sail backwards rather than turning through the wind. That makes sense I guess.

  11. #11
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    Shunting proas dont work well in the confines of a river on small narrow lake, but out in the ocean where you may be sailing out to another island on one tack and sailing back on the other the slowness of tacking is not an issue. With the outrigger on the upwind side it is possible to "fly" the outrigger for a faster sail.

  12. #12
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    If it's the sail rather than the boat you're interested in then Marchaj's - Sail Performance: Techniques to Maximise Sail Power (ISBN 0-07-141310-3) is worth reading.

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