Making Sails

[Jack]

Hi all,

When making sails, the shape line is drawn on the bottom side
of the panel. Does it matter if at the draft line mark, the shape
line is on the high side of a straight line or on the low side at
the draft mark?

What is the usual measurement for the curvature of the shape
line?

Regards and happy sailing
Jack.

[ROY SCOTT]

Jack if you are seriously thinking of making sails then I highly recommend Larry Robinson's booklet "Making Model Yacht Sails". It can be ordered on http/://web3.foxinternet.net/robinson/page34.htm. Another useful item is the "Sailmaking Notes" (T120) from Sails Etc.
I have used these to make my first sail and try out some home thoughts. !!!They look excellent sat on the spars but have yet to be tested!!!

[Arvin S.]

When making sails, the shape line is drawn on the bottom side
of the panel. Does it matter if at the draft line mark, the shape
line is on the high side of a straight line or on the low side at
the draft mark?

Try visiting this site, it shows how they make a set of sails, not for an IOM but the theories are the same just use 4 panels
http://www.amya.org/club100/sailmkg1.htm

As for your question about shape line and draft line. Actually most of the books I have read say that most sailmakers don't even make a shape line anymore. They just use a sailmaking jig to create the sail shape.

Keep in mind that the lines and thus the edges you will be joining (broad seaming) has to be within 10mm, otherwise I am thinking it should not matter.

I have just experimented with my first IOM sails, B rig for starters. I used a home made jig just like in teh website above, and it worked nicely to give a shape. As I said it makes it almost unnecessary to make a shape line anymore. Just draw lines for the 10mm maximum seam and mark where you want maximum draft align it with your jig and start taping.

My experience is with mylar drafting film, so I am not sure if there is a big difference when using softer cloth such as ripstop dacron, etc.

I totally agree with Roy, try to get the references, books, and then you will understand it better. I have gone through maybe 5 references before I even had the guts to try making a set

Good luck!
TTFN
Arvin

[Steve Landeau]

Jack, if I'm not mistaken, you are describing the procedure to make "big boat" sails. One edge straight, one edge curved.
With model boats, from what I've been taught, a "block" is used. The block has a rise in it in the shape of a foil. The sail can be moved side to side to move and/or change the draft.
Don Ginthner at www.GBMY.com has them available on his site.

[Chairman]

Try visiting this site http://www.amya.org/club100/sailmkg1.htm

Hi Arvin

The site seems to require a userID and a password. I can't get in...

[Doug]

The AMYA is undergoing renovation. This page has been open in the past and is probably in the midst of the change. AMYA web site is asking people to report broken links.

[Arvin S.]

Try visiting this site http://www.amya.org/club100/sailmkg1.htm

Hi Arvin
The site seems to require a userID and a password. I can't get in...

Lester the site should not ask for userID or something, Doug might be right you might just have gotten a glitch during their website upgrade.

I just checked out the site just now and the text are there already but no photos yet. I have emailed the webowner informing him about the fact.

The site by the way is for EC12s but as I said great info for basic sail making.

Steve, actually I have read quite a few references in model sail making that uses a shape line and a seam line. However you are also correct and have noticed that specially with working on film materials such as mylar, using a sail block simplifies things plus it does away with the need to be doing a shape line.

TTFN
Arvin