Thanks for posting this Scott.
Interesting. It is an article as opposed to a study. Perhaps using the sailboat analogy was ill considered.

Testing a bunch of kayaks one day, on flat water, and using a GPS, I noticed the Greenland style yaks kicked up a wake and seemed like they were really moving. The steep bow yaks didn't have much wake so they didn't seem as fast. The GPS cut through the false appearances--the Greenlands were all a knot slower.
When I'm in waves around other kayaks, my memory is that the long bow Greenland kayaks seem to bury their bows in waves more and jump up and down. My Great Auk which I steepened the bow (but probably not enough to make it all that different from its original design) seems more level.

I once thought about bow wing-lets, which the theory is that when the bow gets buried the wing-lets lift the bow... I finally rejected the concept for two reasons, first, often when the bow is going to get buried it's not into solid water, it's usually into a mix of water and air and secondly, the most powerful force on a kayak is buoyancy. The proof of this is to see how far you can push a soccer ball under the water--the deeper it goes the more it fights to come back up. Volume trumps shape. (Formula and tests for buoyancy on a submerged object is that once it's completely submerged it will have the same buoyant force all the way down. If you do try this with a soccer ball, wear a hockey goalie's mask--it will hit you in the face. I don't think the designers of outrigger ama's have fully considered this. They should be taller, razor narrow on the keel and wide on top.)

For sea paddling, I'll always go for the longest hull line. Above the practical waterline (is there a term for the part of the hull above the waterline that is likely to be submerged enough times that consideration should be made for fair? ) Well above this area, I say spread out and create volume.

To plug Epic's 18 footer. A friend who's paddled a lot of long fast boats said that all in all the Epic 18 foot was the best: stable and fast. Near similar designs seem completely different. If I bought a factory-yak, that's what I'd get.