> SO: It seems like the hull is 2.5 oz mat + 8 oz cloth, a total of 10.5 oz.

Not quite; woven products (cloth, woven roving) are usually spec'd in oz/sq yd while mat is in oz/sq ft. So, if european suppliers do the same his boat is really 2.5 oz/ft * 9ft/yd + 8oz/yd = 30oz/yd. According to what others have posted, this is a very light layup. Nigel Dennis boats are not very light boats (by design - they are made to stand up to heavy use), so we either measure differently from the Europeans or the use of mat makes the difference. Mat does use more resin than woven products, so that may result in a thicker and heavier finished laminate. I'll let you know when (if?) I get to the bottom of this.