The set should have had two crew and replaced the "sirens" with eagles or vultures, whichever is larger. The birds could have had a new human head but smaller to match the size of the bird.
Then you could have a siren with wings out or folded and the siren could perch on top of the ship. A clear pole able to be attached to the mast could be used as a perch for a siren to suggest it flying around the ship.
