forum.freeciv.org

I propose to add unit function flag "BarbarianTechBoat" - for boat, which can be build by Barbarians when given technology is acquired by any player.
Currently only medieval ships are available for Pirates, it is not possible to add, let say, Motor Boat, because it will appear immediately.

As a kludge for now, you can replace the caravels etc. with motorboats and destroy them in "turn_start"/"turn_begin" signal, the units will be resqued (but their number will be still limited to the original boat).