Sail Restitch

[jojo]

Anyone ever do this kind of work? It's a genoa sail, with sacraficial cloth. The sac cloth stitching is coming undone and needs to be restitched. Two questions:
1) I only have a straight stitch machine; is this ok, or do I need a zig zag?
2) I don't have any scrap dacron sailcloth to sew on...any advice on what kind of tension I'll need to set the machine at (tighter or looser than for normal sewing?)

Thanks,
Jo

[stitchm]

sounds like a uv strip on a roller furling genoa. It runs up the luff(forward) edge of the sail about 1 - 2' width...often done in sunbrella.

Strait stitch is ok, set it at the longest stitch length. How many feet is the luff - lengths above 30' tend to get to be fairly heavy cloth and in that case you'll want to be using a walking foot machine. Probably fairly tight tension will be required.

[Grebo]

If it's not your own boat jojo, May I suggest you stay away, I have done the odd sail repair & it's tough work. First it is a lot of sail to man handle, sorry should that be 'person' handle about, having a second pair of hands to move it about for you would help.
Some bits of the sail mainly the top & bottom can be very thick & tough to punch through.
Personally I wouldn't use straight stitch on a sail because of all the stresses & strains, unless it was an emergency, but thats just my view.  ;D
If you go for it best of luck.


BTW I am thinking big boats here, what size is it ?

Suzi

[jojo]

Grebo, the boat is a 22 footer, and it's not mine. I did work in a sail loft once upon a time, but did mostly canvas, and let the sailmaker take care of sails. But the times I did work on sails, it was easy because they had a designated zig zag machine, and the machines were in the floor, of course.

The owner claims that only the part of the sac cloth that is exposed when it is furled needs to be restitched.
Stitchm, thanks for the advice. I do have an industrial walking foot machine, and I will set the stitch to the maximum.

[Grebo]

Thats not so bad then Jojo you should be able to handle that no trouble  ;D

Suzi

[Gregg @ Keystone Sewing]

Yes, boat sail repair and manufacture is done almost exclusively with a zig zag.  This is because as mentioned the stitch needs to be able to 'stretch' for lack of better terms.  I have seen some highly technical documents from our sail loft guys, and I prefer very much to stay leave that aspect of their work to them!

[Mike8560]

If one knew  the work of sail  repair a loft here I. Sw Florida I think would do well.
Fro
to
e to time I ver asked to do this also and won't I don't know were they can go around here either 

[Gregg @ Keystone Sewing]

If one knew  the work of sail  repair a loft here I. Sw Florida I think would do well.
Fro
to
e to time I ver asked to do this also and won't I don't know were they can go around here either 

Can't agree more...wait, whoa, what was that again? 

[RandyOnR3]

  We do and have done for many years, sail making and sail repair.. We also do a good amount of racing with our FIRST42 and build all our own sails.. the main reason for zig-zag stitching on the fabric is to spread the load over a wider area in the fabric itself.. The only thing you need to watch for in single stitching is the size of the stitch and not to much of it.. when you use a short stitch on a sail, it gives a perferated line for the sail to fail. sails are not static fabric and the load of stiching needs to be spread around..
  The other issue with single stitching the sail fabric is "work-hardning" the fabric..  any place you stitch the fabric, it becomes stiff, the sail or working load of the sail is transformed to the area close to the stitching where its stiff,  every time the sail moves, its movement is stopped at the stitching because of the stiffness and after awhile the fabric will fail..
   This is one of the reasons that new technogedgy shows sails to be glued together like the 3DL Sails over a form......with NO stitching.. we have a new spinnaker or kite on our boat that has no stitching on its main seams crossing the sail.....its all glued together....

[Mike8560]

So Randy  there would be no difference in a zigzag stitch ot two stitch lines with say the same num er of holes it dosent have nothing to do with the thread itself zigzaging and two straight stich line is ok? If so that want I wondered  what's the difference I thought   

[Gregg @ Keystone Sewing]

RandyOnR3,

Very clear laymen terms information.  Any time a sail maker explained it to me, they either didn't know themselves (not that they couldn't make a custom professional racing sail) how to explain it, or the technical documentation was way too over my head to sift through.

Thanks!