I am planning a passage to Fanning Island to deliver medical and school supplies and have an extended stay… how do I determine “slack water” for the English Harbor entrance when I arrive?

Probably the best way to assess the time of slack is to get the tide table for that area – there are various versions available that cover the entire world. The old fashioned way to guestimate the time of slack high is to ascertain the position of the moon at a given place – when the moon is right above (or exactly below) Fanning, this is when you should have high water there. The exact moment of slack water may be affected by local currents as well as wind, but it is a fairly easy way to work it all out.

Jimmy Cornell, noonsite