You don't want ot cut the stuff in half in advance. That would give you square sides which you would have to trim away away later, wasting quite a bit.

Once the hull is finished, sanded, sealed, and the seal coat sanded, then you can unroll your cloth right on the hull. Place it off center so the selvedge edge is close to the sheer line, and maybe 2 inches beyond. Now you can cut the cloth so that you have about 2 inches of excess hanging over the edge all the way around.

That leaves you with a 60 inch wide piece with a notch cut in it. Because the end of the boat uses much less fabric than the middle of the boat, when you do the deck you can start laying out your cloth from about the middle of that notch. Just laying this out on the deck and tugging it along a bit will show you the most economical place to cut.

Again, I suggest using a paper mockup first. You may find that 45 inch cloth will work just as well and be more economical than 60 inch cloth.

Just as an experiment, sketch out an area on a strip of paper which is 2 inches wide and 11 inches long--the full length of a sheet of bond or copy paper. Now draw in this area two 5-inch-long ovals, about 1.5 inches wide--football shapes. Start one at each end of the strip, and leaving a one inch gap separating them in the middle of the strip. Center them on the width of the strip. Now, if you took a scissors and cut out those footballs you drew you will have a lot of paper left over. Snip off the 4 corners of this "waste" where the paper is narrowest. This would be about the place where the footballs were widest. Those four pieces can be flipped so that they cover the inside of the deck. Now cut the remaining piece in half and you get two long pieces which can cover the inside of the hull. It may actually be easier to cover the inside of the hull with two pieces as you can rotate the hull so that the glass is horizontal, not vertical. If you tried doing that with glass covering both sides of the interior, the epoxy saturated top half would fall away from the wood and make a mess!

Now you may find that you get a better use of materials if you don't start cutting the footballs from the very ends, but instead start them 1/2 inch in from the ends. That gives you bigger pieces from those 4 corners, and the footballs touch at the center of your paper strip. Or, you may need a slightly longer strip so you can start the fotballs further in from the ends, and also leave a gap between them in the center, and still have some excess for cutting strips (square cut, or bias) from the remainder of your cloth. A full-sized paper mockup will tell you all you need to know.

To eliminate frayed edges and unraveled fabric, outline the place where you want to cut with masking tape, and cut right through the tape and cloth.

Getting a "bulk" discount by buying a lot more than you need rarely is cost effective. You have to store the excess and keep it clean or it becomes useless. If you have other projects in mind that need these materials, then fine--go for it. Otherwise, save your money so you can buy all the neat accessories you'll want to add later. One way to get a bulk discount that might work is to buy longer lengths of lighter cloth, and use mroe of it. For example: Instead of using 4 ounce or 6 ounce cloth you could buy 2 ounce cloth and use 2 or 3 layers to get the same weight of glass fibers in the same areas. this way you could use 3 layers on the hull, 2 on the deck, and just be working with onel weight of cloth. Instead of buying 8 yards of 6 ounce, you would get 25 yards of 2 ounce. Check your catalogs, do the math, see what makes the most sense.

Hope this helps

PGJ