OMG!!!!! Fernando, you lucky dog! You've called it right on. A boarding ax it is!! Beared blade, wege-type spike end, haft with half balled butt and hole for lanyard ring. Side by side langets, rounded eye socket. Yours has similar traits to both the Brit patterns (shape of spike, side langets, round eye) as well as the French (blade shape). Perhaps made for private purchase, aka privateer vs merchantman. Green with envy!
The real question for me is what period. 19th c. most assuredly, but pre-Age of Fighting Sail or after. Patterns like this existed before 1830, but the spike on yours reminescent of later 19th c. Brit patterns. I suspect more mid century, based on the almost chizel shaped spike. I don't suppose you happened to find two of them while out shopping and don't have the space for the other, at which I will graciously take it off your hands!
Forgot to ask, Fernando, if you suspect this to be a Spansih or Portuguese pattern of the above mentioned types. I'm familiar with French, English, Dutch/Scandinavian, American types. I've seen ones from Sardinia, Italy, East India, one reportedly Imperial Russian pattern. I know NOTHING, however, about the Span/Portuguese patterns, however.