The 1940 medal is different from all the others as it was awarded to a nation’s sailors for wartime mobilization of their largely amateur corps who participated in the rescue of Allied troops trapped on the beaches at Dunkerque.

 

From the citation :

 

Naval forces, fishermen, yachtsmen, ship yard workers, men of all callings left their shops or their desks, some without change of clothing and joined in this gallant effort to evacuate the apparently doomed army.

 

Further:

 

To British yachtsmen who took part in this rescue, both those who survived the hazardous undertaking and those who gave their lives in the attempt, The Cruising Club of America awards its Blue Water Medal for 1940.

 

Commodore Bob Drew arranged that original 1940 medal to be on display for the  anniversary party at the USNA in Annapolis.  He reports the regular home of the medal, on display, is the Royal Thames Yacht Club in London.