1753 Built as a frigate in Havana, Cuba for the Spanish Navy.
Armament 30 guns.
Stanley Gibbons gives her as a ship-of-the-line the book Trafalgar and the Spanish Navy by Harbron has a list with all the vessels built in Havana, and there is not a ship-of-the-line with the name TRIUNFO only a frigate. When you count the gunports there must been more as 30 guns on board, so it looks that the wrong ship is depict on the stamp.
More info on the ship welcome.
Cuba 1989 3c sg3451, scott?