This is an "early Warning" to keep an eye on your yacht that is on a walk on or chain mooring over the period of the 18th to 20th March as exceptionally high spring tides are expected over this period. These tides will be the highest expierenced here in Durban for 18 years? Thanks to P Y C for this info. This is due to the Sun and Moon and some plannets all in alignmentI believe.