My comments on the construction and hull shape of the Little Wing 15.5 are the same as in my review of the Little Wing 12.5: almost flawless both inside and out, and a fast, stable and 'forgiving hull.
I requested a more rugged "expedition" layup be used for my LW 15.5, since I had some minor denting in the hull of my LW 12.5 after several years of weekly use. The expedition layup consists of a carbon/fiberglass/carbon "sandwich" on the outside of a Corecell foam core with a single layer of carbon on the inside of the hull. My boat weighs 32 Lbs vs. 28 Lbs for the normal all carbon layup. It is still very light weight for a kayak of this size with a 14'8" waterline length.
I have paddled my LW 15.5 3-4 times per week for three months in various types of water including 2-4-ft waves and surf landings in Lake Superior. Like my LW 12.5, the 15.5 is fast for its overall length and stable in rough water, and it is almost 'intuitive' in its tracking and turning - it simply goes where you want it to go. The difference is my 15.5 does not dent when making moderately hard landings or encountering unexpected obstacles under the water. I installed Keel Easy keel strips on the bow and stern sections of my boat, the first and last 2-3 ft, which I would recommend for any composite kayak as it prevents abrasion in those areas.
The 15.5, as would be expected with its longer waterline length, is both faster, smoother-riding and has more glide in choppy water than the 12.5. For comparison, I normally cruise in the 12.5 at 3.8-4.0 mph, but in the 15.5 I can average 4.2-4.5 mph. The hull shape seems very efficient. In group paddles with intermediate-level paddlers on Lake Superior and other large lakes I have no trouble staying at the front of the group; I often have to wait for others in their 17-ft kayaks to catch up.
Overall, I am very pleased with the LW 15.5. Now that I have a Little Wing with the more rugged layup, I cannot think of anything that I would change.