Wally wrote
N1EE wrote:

I find it handy to be able to judge high tide
by looking at the moon. I can add or subtract
to estimate when the next high or low tide will
be.

2004-05-04 11:42 PM EDT 8.21 feet High Tide

2004-05-05 5:44 AM EDT Sunrise
2004-05-05 6:06 AM EDT Moonset

You will note that the time of high tide slips
about 50 minutes every day and the interval
between high tides is about 12.5 hours.

A quick scan at my local data suggests slightly less slippage (30-40
minutes), but I'm not sure how reliable the info is. Did you use software
to
derive your numbers?

I study xtide and tables periodically. I see some variations with
what I observe. Generally, I tend to round off numbers. I don't
think it is critical if I'm off a few minutes. Especially since something
like rainfall seems to make a huge difference on our river.