This issue shows barges used by Portuguese and foreign monarchs, several of them now located in the Navy Museum in Lisbon. The stamps don’t do them much justice.
The 1780 royal barge was ordered Queen Mary I. It required 78 oarsmen and was last used in 1957 to transport the Queen of England during her visit to Portugal. Queen Mary I had the ‘Saveira Dourada’ barge built for her daughter-in-law Princess Carlota Joaquina. The barge is 13.5m long and requires 14 oarsmen. It was last used in 1905 to transport members of the British royal family.
The stamps were designed by Alberto Cutileiro, lithographed by Litografia Nacional on enamelled paper sheets with perforation 14½, and were issued on 23 July (according to Michel) or 18 December (according to Gibbons) 1964 .