The spectacle is fascinating. Every six hours or so, the water flows out of the harbour and the yachts slowly sink to the bottom. A skipper seizes the opportunity, trudges through the silt and examines the underwater hull of his yacht.
It is this regular ebb and flow that gives areas such as the Wadden Sea, the North Sea, the English Channel or Brittany their special charm. The constant inflow and outflow of water creates unique natural landscapes with an enormous wealth of species.
On the other hand, there is respect for the effects of the tides, especially among non-resident sailors. The fluctuating water levels add an extra dimension to cruise planning. Due to the draught and changing current conditions, not every destination can be reached at every time of day. Knowing this becomes the decisive criterion.
Entire books can be filled with the theories on how to predict ebb and flow. Fortunately, so much physical expertise is not necessary for sailing practice. Some basic knowledge is enough to understand the processes.
You can read about how fluctuating water levels occur and what is needed for safe navigation in YACHT 23/2010, on newsstands from 27 October.
