How to calculate curve??
 

Hi folks, I realize my question isn't quilt related, but on the off chance someone has the info......
I am trying to finish up the end of a sail cover. [ATTACH=CONFIG]574097[/ATTACH] What we are trying to accomplish is a cover that zips to the existing cover that would wrap around the front of the mast. It seems to me that to allow for the width of the sail in the existing cover, we would have to make the front panel somewhat egg shaped, and probably put a curved zipper on the existing cover too. Is there a rule of thumb to calculate how much curve to put in, or is it just trial and error? Thanks in advance.....

boy, you have a conundrum there.Sorry I can't help.

If it were my project, I would try to remove the cover you are trying to join to, and draw a pattern on newspaper even if you have to tape several sheets together. I have not done any sail work, but I know the ends of canvas where it is hemmed can be quite thick to try and sew a zipper to (if I understand your need), so I would move the zipper just far enough in from the edge to be able to sew one side onto a single layer of the fabric. If I am wrong, try to take a closer photo and maybe I can help more...I am known as a "McGiver" with a sewing machine.

madame kelly has a good suggestion.

You could also start measuring with a tape measure to start getting some ideas of dimensions.

Have you considered using Velcro instead of a zipper? (Not sure that I totally recommend Velcro, either - but it is a thouight.)

Can you post a few more pictures? Sailboats are "unfamiliar objects" to me - - -

Probably a dumb question, but why do you want to cover the mast? To protect the mast? To prevent water from getting into the existing sail cover? Or....?

I would think trying to put a curved zipper in would be daunting. If you sew the outer zipper tape first, the inner one is going to have to be gathered because it will have ripples in it (or you would have to gather the canvas material to fit the inner zipper tape, which would also be difficult because of the thickness of canvas). I would think it would be easier to design a cover that can take a normal, straight zipper application.

I would suggest doing a trial cover, trying out the ideas suggested above, but I'd do it using a light weight like muslin, and make a proto type of the end of the sail cover "boot" to work from vs working from the original canvas sail cover. That would allow you to fit it as needed. If you made it bigger all around, you could then tuck/taper as needed, and that would give you your final size/shape needed.

I would suggest searching online. I found several articles after typing in "making a sail cover." There were several Youtube videos about how to make a sail cover. Hope this helps.

Hi
Go to www.sailrite.com They have free videos how to do this. They will answer questions on the phone.
Hope this helps
Sandra