“Fair Winds and Following Seas” is a gesture of good luck to those we will miss and sailors who have served with honor and courage. The combination of phrases implies that a vessel will have good winds, and not have to pound into the waves. The phrase can be used as a toast or salutation between mariners. It is often used at a “beginning” ceremony such as a commissioning ceremony, as well as in retirement, change of command, or farewell ceremonies.
Following seas are defined by Bowditch’s American Practical Navigator as “A sea in which the waves move in the general direction of the heading” and can be dangerous if the winds and sea are too strong. But the mariners’ traditional blessing implies that both are comfortably rolling in the same direction as the boat.