Lateen sails

Discussion in 'Sailboats' started by velelatine, Nov 12, 2006.

  1. yipster
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    yipster designer

    :) your right and agree on the white sail, i never was good in abstract painting
     
  2. pebbletripper
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    pebbletripper Junior Member

    I am researching the idea that the invasion fleet of william the conqueror used a form of lateen sail with a crude form of roller reefing. This may sound bizzar but check out my trial using a viking type craft I built myself . type in bayeux sails project in you tube to see the video. All comments welcome:) Images of the bayeux ships can be seen on my website www.davidjones.uk.com soon to be updated
     
  3. ancient kayaker
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    ancient kayaker aka Terry Haines

    I plan to make a small lateen sail for a 10 ft (3m) kayak to try out this Summer.

    It will not have a mast, just the yard, attached at the bow. I am looking for the low aspect ratio to keep the CoE low with decent windward capability. The yard is fixed so it cannot be rotated to sail at different points but the sail foot is simply let out: this will generate a variable vertical lift component that might help cancel heeling force on a broad reach. No "bad tack" side. It will hinge down for bridges. With 10 ft (3 m) of yard extending from the pulpit (?) at 45 deg I can hang a 25 sq ft 4.5 sq m) sail. I previously tried 15 sq ft area, was actually able to work upwind but not easy, so 25 sq ft should be sufficient. CoE will be 4.5 ft (1.4 m) back from bow which is about level with my shoulder: I plan to use a hand-held boom to control the clew. For downwind I may have to jibe in a series of broad reaches.

    I'm not sure how well it will work but I'll try it
     
  4. pebbletripper
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    pebbletripper Junior Member

    one interesting thing about the bayeux sails images is the use of norman shields either for or aft to help compensate for problems with either upwind or downwind sailing .When I used shields mounted to the rear on a small lake with a square sail I found that instead of drifting hoplessly down wind sideways I was able to travel upwind very succesfully. A small vertical element to the rear of your vessel may be an excellent companion but a pain downwind. If you look at many vessels from egyptian times they have a raised feature at the rear like a palm frond (a small rigid mizen ) it takes the strain off of the steering for starters. Good luck
     
  5. ancient kayaker
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    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    Perhaps an ancestor of the yawl. Nice web site!

    I built a small canoe which had a pronounced preference for feathering upwind, not a bad habit and better than its oppoite but overdone in this case. I did not expect the pressure of the wind on my upper body to be so pronounced. I added a skeg to fix the problem, runs straight as a die and is great on a big lake but it is a bear to turn.

    I have a new canoe awaiting a paint job which is similar but with a slightly raised sheerline forward and a hair more rocker which should cure the problem; it will be better for the river trips I take. It is the same technique as you describe.

    It promises to be a busy year.
     
  6. sharpii2
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    sharpii2 Senior Member

    A very interesting idea.

    The sails shown on the tapestry DO look triangular.

    My guess is they were, but rigged like square sails.

    None of the yards shown seem canted to any large degree.

    I don't see where you get the roller furling idea from. I can see that would require two yards. One would attach to the mast and the other would be held by the first only at its ends. I see a great weight penalty there.

    why not just lower the yard, slab reef the sail, then raise it again.

    From what I have read, the lateen sail never really worked on the North Atlantic. One of Columbus's ships was so rigged when he set off, but was quickly changed to a square rigger once he made a nearby landfall.
     
  7. pebbletripper
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    pebbletripper Junior Member

    In this case the storm spinakers held by the helmsman and tied off at the stern would be furled by hand by twisting ,simple to regulate and allowed to billow out in gusts . I have seen such a sail that appeared in a programme filmed in Lake Victoria . The small craft had a side rudder and the helmsman held the sail which was an over long triangle from his position in the stern. Easier to adjust than trying to reef in a storm over the heads of agitated horses with 700 other boats all around in the dark !
     
  8. sharpii2
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    sharpii2 Senior Member

    Viking lateens?

    My guess is that the tapestry showed the fleet either making sail or beginning to strike the sail. As the square sails they used at the time had no boom, it seems logical that gathering up the foot of the sail would be the first step in furling and letting loose the foot would be the last step in setting sail. I don't believe they had foot ropes on the yard, so the sail could be gathered up to the yard, as in much later square riggers. Instead, they probably lowered the yard. One can imagine what a mess that would be if the foot of the sail wasn't gathered first.

    Just a thought.

    The traditional lateen had the virtue of being a better windward sail, as it did not have a long, loose luff that could buckle inward. But it had a big vice. The sail had to be rotated around the front of the mast every time one changed tacks. Either that, or the butt of the yard had to be pulled around the back of the mast, so it could always be on the leeward side. Now imagine doing that with a yard that weighed a ton or more in gusting winds and heaving seas.

    The square rig was simply more secure and more handy. And it could be made to go to windward. At least in what we would today call a close reach. A long pole was often used to hold the luff out into the wind and keep it from collapsing. I believe it was called a beatrice, or something like that. The other end of the pole was braced into a socket on the deck or windward gunwale. Hence the tradition of calling 'tacks' 'beats'.
     
  9. pebbletripper
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    pebbletripper Junior Member

    Have a look at my you tube video . type in bayeux sails project and ignore the first bit of sailing as I tried to sail across the wind. one interesting thing is the number of other images of triangular sails used downwind in the 11th c . one of the best is a storm scene try - ship boyana church in google images. And there are many more around the med. If you send me an email I will send the images. Also if you want to see the bubble trails under a viking craft and how they form , again look on the you tube page davidjonesfm@onetel.com I will repeat in case emails are restricted davidjonesfm(at sign)onetel.com
     

  10. troy2000
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    troy2000 Senior Member

    One of my favorite crackpot theories is one my dad came up with. Whatever else could be said about his mental facilities towards the end of his life, nothing ever impaired his imagination.

    He figured the way Vikings got upriver past rapids and waterfalls was to put a bigger sail on a longship, fly it up out of the water like a kite, and reel it back in upstream of the obstacles. According to him, that was the origin of the stories about flying dragons.:)
     
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