Self tacking jib options

Discussion in 'Multihulls' started by Scuff, Jul 13, 2021.

  1. Scuff
    Joined: Nov 2016
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    Scuff Senior Member

    I'm trying to find information on the different ways to implement a self tacking jib. My plans came with a club footed setup. Are there improvements to be had with this setup? I've seen other pictures that show a curved jib track with no boom, and then the Hoyt boom. I'm sure there are other ways to do this.
    I'd be grateful for any insight on the different approaches and thoughts on the strengths and weaknesses.
    Thanks
     
  2. bajansailor
    Joined: Oct 2007
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    bajansailor Marine Surveyor

    Is this an existing boat, or one that you are now building?
    What class / type is she?
    If she is already sailing, can you post any photos of the existing set up?
    Re 'improvements' - there should be less labour involved in sheeting the jib in on each tack, especially when short tacking.
    But generally, I think that you would have more opportunity for tweaking the shape if you had a blade jib or similar, rather than a boomed jib.

    Edit - Re tweaking, I just saw the very neat arrangement in the photo below posted by The Q - what a brilliant idea.
     
    Last edited: Jul 13, 2021
  3. The Q
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    The Q Senior Member

    Another way is to extend the Jib club forward of the forestay and take a wire / string up the mast then back to the helm so that he can control the tension on the luff like a vang..
    [​IMG]
    This arrangement is what I'm fitting to my mini open keel boat, also it's the windward jib sheet that controls its position therefore I can pull the jib out to the opposite side to the main when running. Note My extension to the club is forward of the bow so keeping the same sail area as normal.
     
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  4. Scuff
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    Scuff Senior Member

    I'm building the boat I'm almost ready to start on the main hull. It's a horstman 27-9. Doesn't the club provide a vanging function? The sheet leads forward to the base of the boom and then turns to a winch on the portside coach. I was thinking that would pull the leech down. Would a curved traveller be an improvement?
    Q, do you have any additional pictures/info that looks like a good approach.
    Thanks.
     
  5. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    Tracks, Hoyte and club footing all could control angle of attack and foot and leach tension.
    BUT
    I've never seen the control lines added to a Hoyte.
    The one track tracker I installed foot and leach tension lines on turned out to be crewed by salty dogs who wouldn't learn new tricks. It could not control the foot and leach tension while the clew was outboard of the track.

    Hoyt booms automatically fatten the jib's draft as the sail is eased. Hopefully at the rate that is best for your boat.

    Club foots can use the same outhaul system as on a main boom to control foot tension on all points of sail. The previous mentioned extend club would tension the leach on all points as well. Clubs can be cleared off of the foredeck but bow pulpits can interfere with them.
     
  6. Scuff
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    Scuff Senior Member

    Blueknarr, the design I have does use an outhaul for the foot. There's also a note that says in order to drop the sail the outhaul will have to be eased. Can the outhaul be operated from the cockpit? That would be cool if so. Would a curved track be an improvement with this setup? As drawn it uses a section of straight track.
     
  7. Blueknarr
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    Blueknarr Senior Member

    I don't see your design, so my comments have a few assumptions.

    You say that the club must be eased to drop sail. Must be a very high clew. With the sail's foot being longer than its LP.....Self tacking tracks lose effective shaping control as the clew gets farther away.

    Run the outhaul to the tack then back to the cockpit. Simular to running a mainsail outhaul back to the mast and down

    I assume the track you referred to is for the vang. If so no track needed. Terminate a line on one deck edge. Up to a block on the club. Down to a block on the other edge of the deck. Finally aft. It will lose effectiveness when the club's block travels overboard. Then a wisker pole could provide leach tension
     
  8. Blueknarr
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    Blueknarr Senior Member

    Just thought thru the geometry a bit more.

    All jib feet are longer than the LP.

    Curved vang track on a flat deck or compensating for deck camber will maintain constant tension throughout all points of sail. Trackless or straight track will reduce tension when the boom moves inboard. But you will probably want different tension on different points of sail.
     
  9. The Q
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    The Q Senior Member

    Sorry no additional pictures that's from an international canoe site, try looking around there. For my own boat not as High performance as an IC, the mast I'm using has fittings for a spinnaker, as a single hander I'm not using those, so effectively I'm using the spinnaker halyard to the jib club end. The Club is 6 ft long, with 1 foot of it beyond the forestay. I'm arranging the jib club on a universal joint to the bow fitting, the jib stay from an eye on the jib club. the jib being furling set up. still building that at the moment..
     
  10. Scuff
    Joined: Nov 2016
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    Scuff Senior Member

    I attached a side view of the sail plan and a deck layout. The boom is 7' long and sits aft of the forestay 3'6". The track is 48" wide. The foot on the jib is listed as 9'2". Luff 31'4" leech 28'9".
     

    Attached Files:

    Last edited: Jul 14, 2021
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  11. Jethrow
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    Jethrow Junior Member

    I don't think anyone has really stressed the fact yet that if you have a curved self tacking track with no boom then the track needs to be radiused through the plane of the LP.

    This leads to the track curving up at the ends, and on a boat with a cambered foredeck the track will need some pretty substantial support.

    I thought I had a better photo of my setup but this is the best I have at the moment...
    upload_2021-7-20_8-23-5.png
     

    Attached Files:

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  12. Scuff
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    Scuff Senior Member

    With the curved track is there any benefit to keeping the boom? If the boom is retained does the curved track still need to match the LP .. it sounded like it might not. Thanks for the pictures of your setup. How did you measure to keep the track in plane?
     
  13. Blueknarr
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    Blueknarr Senior Member

    Tracks will only control a boomless sail while it is in very close proximity to the tracks. The more string between the sail and track, the less control the track has.
    The boom extends the range of control.
    LP curved tracks will maintain a constant tension throughout a tack. Straight or non-LP curved tracks will maintain a tension on either tack but not while tacking.
     
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  14. Jethrow
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    Jethrow Junior Member

    Scruff, I don't have a jib boom, my clew is very close to the track.

    With my setup, when going upwind, the car is just above the inner end of the support block seen in the photo. This is a sheeting angle of about 9 degrees, maybe a little less even.

    Easing the car down the track to the outer end gets me to about 30 degrees sheeting angle. This means I have a large amount of trim angle without needing to ease the sheet much, and I can ease the sheet more to get further downwind angle. The clew of the jib is about 4" from the track when sheeted tight.

    The plane of the track is 90 degrees off the tight forestay and the track is radiused to this distance. It is easy enough to visualise approximately where the track will be by holding a batten against the sail and extending out along the approximate jib sheet and swinging the clew with a tight leech and foot through the sheeting arc. My system uses a cascading purchase system so no winches are needed.

    The jib sheet goes from the clew, through a block on the car and forward to the base of the forestay. This allows the jib car to travel the length of the track without the sheet tension changing. Having the end of the jibsheet located the same distance from the centre and the tips of the track is important so that the sheet tension does not change throughout the sheeting angle range. There is a similar equisdistant point up the mast but it is usually much higher. Some self-tacker boats use this up the mast sheeting to keep the foredeck clear of swinging ropes.

    Hope this makes sense and is somewhat helpful...
     

  15. Scuff
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    Scuff Senior Member

    I think based on my understanding that the design provided is a good one and pretty simple to implement vs me attempting the curved track. Since this is a boomed sail would a vang be a good upgrade much the same as it is on a mainsail? Thanks for all the help on this I really appreciate it.
     
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