Hi Fernando,
I think Atlantia may be right about your piece. It may be an 'optical illusion' but there appears to be evidence (on the surface of the iron) that bands once held the cannon to a handle (see pictures below). I know the general agreement is that this is a signalling 'device' (and it probably is) but if a 'maritime' item ..this would 'double-up' nicely as a grape shot/ 'shrapnal' hand cannon ...useful for clearing the 'decks'. Most Navys of the time, would not want to laden their sailing ships unnecessarily (little space and the excess weight would impede speed and manoeuvrability) so items tended to have a 'dual purpose' ....or in your cannon's case a 'duel purpose'
Kind Regards David