1827 (3rd May) ”SHIP LETTER GRAVESEND” and ”SHIP LETTER MARGATE” both boxed 2-line cancels applied on ONE folded envelope by the ship letter office London. A folded letter with cds ”ELBERFELD 3/5”, Germany sent to London with red ”FRANCO” indicated payment the nearest port (prob. Bremen), ”Gravesend” cancelled by crutched cross and re-stamped with correct ”ship letter Margate”, both cancels together is an UNIQUE KNOWN combination! (M)