 They used the barge or the balinger ("barinel"), which were ancient cargo vessels of the Mediterranean Sea with a capacity of around 50 to 200 tons.These boats were fragile, with only one mast with a fixed square sail that could not overcome the navigational difficulties of southward oceanic exploration, as the strong winds, shoals and strong ocean currents easily overwhelmed their abilities.The caravel has origins in earlier Portuguese fishing boats built in the 13th century based on the medieval Islamic "qarib".