Fri Feb 08, 2013 10:51 pm
I sincerely hope there is no way to do this.
Ancient warships were occasionaly decked out with stone- and spear-hurling engines, but these were usually just longer ranged anti-personnel weapons.
The function of most catapults and ballistae was to clear enemy troops from a section of wall that needed assaulting, rather than to bring down the wall itself. That was usually done with rams and sapping operations, and is described at great length in Frontinus' Stratagems. Frontinus also describes counter-moves. My favorite defensive tactic was to set bowls of water on each section of wall: you could tell if someone was trying to undermine the wall because the surface of the water would pick up the vibrations.
The most famous use of ships for taking a city was during Alexander's successful siege of the city of Tyre. Ships were necessary because Tyre sat on an island just offshore, but they were hardly the main event. The city was taken because Alexander built an assault mole from the mainland to the island.