Tidal flows around Fair Isle
Whilst planning a recent passage from Pierowall, Westray to Fair Isle's North Harbour we struggled to align the information in CCC Sailing Directions, not only with The Admiralty Tidal Atlas but with information given on pages 66 & 68 of the Sailing Directions themselves.
A phone conversation with the skipper of The Good Shepherd (later confirmed by our experiences on arrival & departure) show page 68's guidance to be more correct than page 66.
Supplementary advice:
Avoid arriving <1hr prior to Local HW, which approximately the same as HW Dover.
Make an approach from the North in order to avoid a long slog against the tide up the East coast.