New moons & Full moons are responsible for Spring Tides. Moon's & Sun's gravity in line.

Question

1st quarter & last quarter are responsible for Neap Tides. Moon's gravity 90 degrees to Sun's gravity.

This is generally accepted & understood.

However if you look in a tide table or nautical almanac you will note the highest spring tide in a cycle will occur 2 days after the new & full moon.

Likewise the smallest neap tides occur a couple of days after 1 st quarter & last quarter.

So the generally accepted situation as described above is not in fact entirely accurate and somewhat of a simplification.

Please can anyone explain in more detail.

Thank you

Mike

Answer 1

http://en.wikipedia.org/wiki/Tide

In most places there is a delay between the moon and the tide. The reasons vary, but in general, it is due to some delay in the water flow caused by restricted inlets or shallow depth. It varies considerable, I experienced this in Rhode Island, and Panama. That wiki article notes some examples of the age of the tide. Local tide tables usually take it into account.