Here is the story of the tripeiros nickname. In 1415, ships and boats were built on the banks of the Douro to conquer Ceuta. The reason for this adventure was secret and in the shipyards the rumors were many and varied.
One day, Infant D. Henry the Navigator unexpectedly appeared in Porto to see the progress of the work and, although he was satisfied with the effort made, he believed that more could be done. Then, the Infanta confides to Master Vaz, the faithful person in charge of the construction, the real reasons for the company. He asked the master and his men for more efforts and sacrifices.
Master Vaz assured the Infanta that they would do the same thing as about thirty years ago, during the war with Castile. They gave all the meat in town to supply the boats and ate only the guts.
Moved, D.Henrique told him that this name of "tripeiros" - a nickname given to them thirty years ago - was a real honor for the inhabitants of Porto.