: That is good advice. No matter what hull you paddle, you need to have good
: strength and stamina to propel it at high speeds for long periods of time.

My interest was to inform those that don't paddle regularly that saddling themselves with a pint-sized cutsie-pooh canoe or kayak will mean more work if they want to go any distance. And they may have trouble keeping up with those in longer hulls.

: Do you have any source that correlates glide with waterline length? I have
: never heard that...

I read it somewhere long ago and it has seemes to be my experience.

: Are you talking about Greenland kayaks only? - if we take into account ALL
: arctic kayaks, they ranged from less than 9' long for the Koryak types to
: 26' for some of the East Canadian types. Not all native kayakers had the
: same answers to what kayak works best; most if not all tailored their
: craft to suit local conditions and patterns of use which were rather
: different than what most modern paddlers encounter. There is no rule that
: correlates length with sea worthiness, there are too many exceptions that
: indicate longer kayaks are not always better, even for strong paddlers;
: doubly so for novice and less-strong paddlers who do not have the strength
: to continually push a longer hull to the speed where it sees any
: advantage.

Native canoes were all fairly long, too. Since assembling the required materials was difficult for any native boatbuilders they would have built short rather than long. So, I surmize, they had a damned good reason to build long.
I wasn't commenting on seaworthiness. Some of the original baidarka recreations were only usable by the most expert of paddlers.
For paddlers who are expert or novice the same metrics apply. If you want to spend long periods on open water you will reduce the required workload if you shy away from short waterline boats.
At some length wetted area and weight will make matters worse. But in the range we operate in, 12'-17', I don't think that comes into play.
All of the special use kayaks I'm familiar with(recovery and retrieval) were intended for sheltered water and short periods of work. I don't think those fit into this arguement.