A Lake Winnipesaukee R.P.O. cover dated August 30, 1948, franked with the 3¢ "100 Years of Progress of Women" commemorative — a thematically matched same-year issue. The printed cachet commemorates Made in Laconia Week, August 30 – September 6, 1948, incorporating the Laconia city seal and the period claim that the Mail Boat "Uncle Sam" is the world's oldest floating post office on an inland lake. Addressed to Bridgeport, Michigan. Back flap shows significant brown staining; front and cancel are clean. A rare convergence of Marine RPO postal history, women's history philately, and New Hampshire civic ephemera.