RE: My newly built Dumas Ace Sloop
No I have four rings on mine also.
this should help you out alot, I took measurments of the spacement of the rings etc.
From the bottom of the main mast to the screw eye for the boom I have mine at 1-3/4 inch. The bottom ring I sewed onto the corner of the sail material and thats at 2 inches from the bottom of the mast.The spacing between the four rings are at 4 inches apart. The sail material reminds me of those old parachute pants, or windbreaker jackets.
yeah you just sew the rings right onto the sail, and lace the sail onto the jib boom & main boom...I'm not crazy about it either but I built on of these boat back in 1983 and it held up till it got lost between moves around 2003. I do suggest using clear testors liquid cement and gently dab a drop around each stitch for piece of mind....
Its pretty tough stuff and I just used a sewing needle and some fishing knots. The lacing for the sail to the boom is roughly 1 inch apart....
Over each knot i used clear Sig dope, you can get away testors liquid cement or clear RTV silicon too.
i would reconmend buying a pin vise from sears for around 5-8 bucks or home depot, even hobby lobby has them. The vise hold very small diameter drill bits so you can start the holes to screw the screw eyes onto the wooden dowels and deck without spliting the wood...Also the very top of the mast your going to drill a small hole thru the top to run the line from the bow to stern. A screw eye is placed 1/2 inch from the top to run a line from starboard to port.
The outer wood of this boat is a thinmahogony ply and my first Ace I used a small can of minwax varnish & sealed it up with a finishing resin and it turned out great. A white or at least a bright paint job makes it easier to see on a larger lake.....This boat sailed very well in the lakes in the forest preserves around the chicaoland area...