When I was trying out and looking at boats in search of one that would serve as a long distance touring kayak, I too was very aware of boat width. Along the way, I looked at some very narrow boats; I even tried a few out and merely sat in some. Long distance to me means that I will be spending long periods of time in the saddle. Not one of the ultra skinny boats was comfortable for more than a few minutes. One boat I tried was so tight that I couldn't even squirm around.
I began to wonder if some designers are more concerned with skinny as a status symbol as much as a performance factor. I've come to believe that a properly designed boat doesn't sacrifice one aspect in order to maximise another--especially if the kayak is going to do more than one thing.
I'm sure that the guys at Novus Composites could have gone for a narrower boat when they designed the Expedition, but what I've come to realize is that they do things their way and as far as I've seen it's usually for a very good reason. I personally wouldn't want to give up one ounce of this boat's stability and believe me, speed is not a problem.
Width does matter to some extent, though the issue is how much stability/comfort etc. do you want to give up in the process.
I'm about 180lbs (should prob be 170) and could easily fit into a 20-21 inch boat. From the rough formula I used to calculate top boat speed, an increase from say 20 to 25 inches can shave an entire knot off the top speed. Another thing, the hull design of your boat is designed to track really well, so your views about skegs may not apply towards other boats.
Again, this boat is designed for larger people, it's 24" wide and 13" deep, that is a LOT of volume. This boat is a lot like the Current Designs. So stating a starting weight of 190 may in fact be accurate.
Though skill is required to get a boat to top speed, moot point for most people and hence the NC 19 is fine for anyone. I feel that I am really putting in more and more effort in my 16.7 and I'm not going any faster, I can feel the paddles just straining to keep up. Hence this thread ..