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Thread: Bad workman blaming tools?

  1. #1
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    Default Bad workman blaming tools?

    I've got the same boat and sail as the one shown below. 15' Wenonah Prospector and an Endless River sail.



    I've been out a couple of times and found it fine for going down wind and across the wind. I've been using a combination of an old ottertail as a lee-board and jamming a paddle to accomplish the same thing (sometimes both together) and was getting good results adjusting the board/paddle position back and forth to move between a broad reach, beam reach and what would have been a close reach if the boat had kept moving.




    So why can't I sail upwind?

    A bit of reading suggests the reason for not going anywhere upwind is:
    (a)the unsophisticated sail not providing enough drive (big problem)
    (b)too small a leeboard not giving that drive something to work against (smaller problem)

    But I've also seen people saying they can sail upwind with this rig.

    So if I want to sail upwind, do I need better skills or a better sail?
    Last edited by AHPP; 18th-April-2014 at 11:56 AM.

  2. #2
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    What angle to the true wind can you manage?

    What other craft have you sailed?
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  3. #3
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    With due consideration to the fact I could have misjudged how well I was doing, I reckon I made 90 degrees (maybe a little less once I'd been pushed sideways a bit). This is without any kind of weathervane on the boat and without recording the track or anything. Just judging the wind by looking at it and aiming for buoys, points on shore etc.

    Have sailed Laser and Topper dinghies 4 or 5 times, not competitively but I could make them work OK single and double handed and with and without jib.

  4. #4
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    Factors:
    1 - Parasitic drag - the hull and paddler have a greater area than the sail.
    2 - Sail shape and Trim - Boomless sprits have a bit of a reputation for being very difficult to trim effectively - much practice required.
    3 - Sub optimal appendages - getting to weather effectively depends on the L/D ratios of both air and water foils - both pretty poor in this case - and if the boat stops moving then water foils become almost completely ineffective.
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  5. #5
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    Can you explain 3 in simpler terms please.

  6. #6
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    L/D is the lift to drag ratio.

    For a reasonable explanation see "High Speed Sailing - Design Factors" by Joseph Norwood jr, isbn 0 229 11595 0
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  7. #7
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    If I was seeking a shortcut answer (which I am), do I have any hope of sailing to windward with my setup?

  8. #8
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    You ought to be able to better 90 degrees, but it might take some practice and perhaps a better leeboard.
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  9. #9
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    Ta.

  10. #10
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    I don't see the size of the leeboard, and don't understand the beavertail.
    An actual leeboard of bigger size than a paddle, and an actual rudder would help.
    The leeboard needs to be placed in the proper position relative to the sail, the center of effort of the sail needs to be a little ways aft of the center of the leeboard. Center of Effort can be taken as the center of the sail and leeboard (in the water). If the center of the sail is far aft of the center of the leeboard you won't be able to get it to turn away from the wind, and if the leeboard is too far aft of the sail you won't get it to turn up into the wind.
    The angle of the main sheet shown allows the top of the sail to twist off. This eliminates much of the sail area for going to windward. Move the attachment of the sheet farther forward, so it is pulling more down (but not completely down)
    You might look at some of the other threads on this site just to see an example which is working well.

  11. #11
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    Quote Originally Posted by MarcUp
    I don't see the size of the leeboard, and don't understand the beavertail.
    An actual leeboard of bigger size than a paddle, and an actual rudder would help.
    Quote Originally Posted by AHPP
    I've been using a combination of an old ottertail as a lee-board and jamming a paddle to accomplish the same thing (sometimes both together)
    Was a paddle; is now a lee-board. I have a bit of strap round the centre thwart and what remains of the shaft and stuff the blade down the side of the boat.
    I did wonder whether it was too small but it's what I have.



    -------------------------------------------------

    Quote Originally Posted by MarcUp
    The leeboard needs to be placed in the proper position relative to the sail, the center of effort of the sail needs to be a little ways aft of the center of the leeboard. Center of Effort can be taken as the center of the sail and leeboard (in the water). If the center of the sail is far aft of the center of the leeboard you won't be able to get it to turn away from the wind, and if the leeboard is too far aft of the sail you won't get it to turn up into the wind.
    Quote Originally Posted by AHPP
    ...and was getting good results adjusting the board/paddle position back and forth to move between a broad reach, beam reach and what would have been a close reach if the boat had kept moving.
    The centre of effort and centre of lateral resistance relationship is fine, I think.

    -------------------------------------------------

    Quote Originally Posted by MarcUp
    The angle of the main sheet shown allows the top of the sail to twist off. This eliminates much of the sail area for going to windward. Move the attachment of the sheet farther forward, so it is pulling more down (but not completely down)
    Quote Originally Posted by AHPP
    (a)the unsophisticated sail not providing enough drive
    I think this is what DougR meant when he was talking about the difficulty of trimming this sort of sail. I could run the sheet from the bottom of the sprit to the standard bottom corner to try and add tension (and reduce twist) but I'm not confident it'll work. Equally, I could I split the sheet to attach at the bottom and top corner of the sail but am similarly not confident it'll help.

  12. #12
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    The Ottertail does look a little small, better to go big. Small will significantly penalize you as far as going to windward. Additionally if you cannot keep the ottertail perfectly in line with the center of the boat you will have a terrible time. Thanks for explaining/ showing what you are using. You would probably be better off with a flat board hung over the gunwale to keep it straight.
    Don't attach the sheet to the top of the sail you will have lots more difficulty in adjustment.
    In the picture above there appears to be a cross member (wood) just in front of where the sheet is attached now. If that duplicates your setup, just move the attach point forward. I'm not sure about using the bottom of the spirit, my imagination is not working I guess.

    Good luck.

  13. #13
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    Cheers.

  14. #14
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    I bought an old mirror centreboard off ebay for about a fiver, I think, when I was looking for a leeboard for my canoe. Solway Dory sold me a sail and a thwart with angled iron to hang the board off and clamping handle to hold it on. The board was almost certainly bigger that it needed to be, but worked very well for going upwind (and I could have cut it down if I'd wanted/needed to). I have since picked up a proper foil (the mirror centre board is barely shaped beyond a slight trailing edge) second hand, but my point is you can probably improve your leeboard very easily.

    If you ask around you may well be able to get a better sail second hand, if cost is discouraging you from going down the SD route. I found them very good value, though, and found that making my own leeboard was the way to save money while starting out.

    HTH
    Ian

  15. #15
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    I'm sure I have a suitable piece of wood back home. Thanks.

  16. #16
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    Not to create a firestorm of controversy, but you HAVE heard this joke, right?

    Q. What is the universal sign of distress in a small open boat?

    A. A boomless spritsail.



    From a long and (sometimes) learned discussion on boomless spritsails - worth reading.

    http://forum.woodenboat.com/showthre...add-sprit-boom

    It includes this gem of a picture
    Last edited by DougR; 19th-April-2014 at 04:19 PM.
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  17. #17
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    I'm not especially bothered by what the potential of the rig is long as I know what the potential is. I already consider myself in bonus territory being able to go across the wind.

    Had a read of the thread and I think I get the idea. I take it you like that pic because it's a boomless sprit that works?

  18. #18
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    Nah - its just a very pretty picture.
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  19. #19

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    For what its worth, looking at your picture I think you are unlikely to achieve much better (if any) than 90 degrees to the wind. In my opinion the sail needs to be further forward and your leeboard would need to be directly under the center of effort for the sail.

    I would enjoy the sailing with your current rig and if necessary paddle upwind.

  20. #20
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    The picture DougR posted looks like it would do pretty good upwind especially on that tack.
    If the leeboard on the other side and the rudder are big enough I would guess it is as good as many other non-bermudan sails.

    That picture looks like my suggestion of a higher angle on the main sheet might be completely wrong.
    The sail is setting pretty good and doesn't look like there is any significant twist.

    I suppose I ought to actually sail one before making suggestions.
    Last edited by MarcUp; 21st-April-2014 at 12:33 AM.

  21. #21
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    The main problem with the Endless River sprit sail is that it is too small for efficient upwind sailing, and it wont generate enough power unless it is blowing really strongly. Add to that a less than ideal shape, an inefficient leeboard etc and you are up against it. You can definitely blame your tools. However, even with a good sail and leeboard, if you are not a good sailor, you will only go half as fast and not point as high as a good sailor.

  22. #22
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    Thanks, all.

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