Dan Best wrote:

It may be true that some overestimate wave heights by this much, but
it is hardly universal. For moderate waves, I am quite confident in
my estimates. It's really quite simple. If you know the height of
your eye above the water as you sit in the cockpit (for instance,
mine is just a hair over 6') then if the wave top is above the
horizon while you are in the trough, it is over 6', if it doesn't, it
is under 6'. By adjusting for how much it appears to be higher/lower
than the horizon, you can then get a very good estimate for waves up
to about twice your base height.

You are probably right about your wave height estimates because that is
essentially the proper method for estimating. When you just look out from
the cockpit and guess though, they'll look twice as high. Often, you'll
have to lie down at the rail to get the proper eye height to measure those
"six foot" waves.

--
Roger Long