Corollary: Perhaps the best way to transport a hero by water is to have him flying (with a bat or other air unit), and then to group him/her with one or more navies. This is better than making the hero into a navy at a port. (You sacrifice a little mobility, since your hero often has only has 14-18 movement points, instead of the 20 that a navy has, but you don't sacrifice movement points converting him to a boat. Nor do you need to find another port to get your hero out of the water. Also, your hero is not reduced to the naval unit strength of four.)