Jeff wrote:

While the Rule of 12ths is a very handy tool for estimating the tide
height at any point in the cycle, I would be very careful of using to
extrapolate total range from one hour's observation. For instance, if
your observation were off by one inch, then you might mis-estimate the
full range by a foot.

I'd agree with that. The way I read the question, I took it that the only
information available was what could be observed over the next hour, hence
the extrapolation. I'd much rather know the tidal range and work from big to
small. :-)


--
Capt Scumbalino