:Rather, just measure it at the points where
: the waterline crosses the stems. Just my humble suggestion.

Hi Roger,

The stems, especialy on a Greenland kayak, slope up and away from the keel
near the ends. If you were to measure the rocker, as you say, at the
intersection of the waterline and the stems, then the reading couldn't
possibly reflect the actual rocker. Some kayaks have flat keels, but steep
stems. In other words, they actually have no rocker, but at the stems, the
waterline would indicate that there is lots of rocker. The most accurate
measure of rocker would be at the intersection of the keel and stems. The
measurement of which would be from that point ( stem / stern/ keel transition
to the baseline represented by the lowest point of the keel.

FWIW, I posted a diagram of the Sea Riders side profile a couple days ago,
displaying this measuring method. Perhaps you didn't see it or it
wasn't clear.

Best,

Tom