The spreadsheet is presented in the format of a secondary port difference table.
When the standard port tides are entered (yellow boxes) the sheet returns the secondary port tides. The example above represents the tides at Watchet, North Somerset. This spreadsheet could act as a template in order to represent any other secondary port tides. Standard port tides between 00:00 and 03:00 must be entered as (24+ the time). Times are entered in the format hh:mm Time differences are entered as whole minutes eg 105 represents 105mins, which is 1 hour and 45 minutes
The spreadsheet predictions can be checked against 'Easytide'. The following table makes such a comparison: