Where did the pea coat get it's name?

PEA COAT SAILORS WHO HAVE TO ENDURE PEA-SOUP WEATHER OFTEN DON  THEIR  PEA  COATS  BUT  THE  COAT’S  NAME  ISN’T DERIVED FROM THE WEATHER.

 THE HEAVY TOP COAT WORN IN COLD, MISERABLE WEATHER BY  SEAFARING  MEN  WAS  ONCE  TAILORED  FROM  PILOT CLOTH - A HEAVY, COARSE, STOUT KIND OF TWILLED BLUE CLOTH WITH THE NAP ON ONE SIDE. THE  CLOTH WAS SOMETIMES CALLED P-CLOTH FOR THE INITIAL LETTER OF THE WORD AND THE GARMENT MADE FROM IT WAS CALLED A P-JACKET - LATER A PEA COAT.

THE TERM HAS BEEN USED SINCE 1723 TO DENOTE COATS MADE FROM THAT CLOTH.