The Chinese have been seen test firing artillery, tanks and rocket launchers from the decks of cargo ships. Except for the tanks, this is not unusual. During World War II, the Allies mounted multiple rocket launchers on ships to provide fire support for amphibious landings. During the Vietnam war, American artillery was mounted on barges for use along Vietnamese rivers. But the Chinese are taking this a step farther. Apparently they intend to use large (130mm and 152mm) guns from the decks of cargo ships, to provide direct fire against shore targets. Normally, these big guns fire "indirectly" (up, at an angle, at distant targets the gun crew cannot see.) Firing directly at a target they can see is the only practical way for artillery crews to use artillery on ships. The big guns on warships have a lot of additional fire control equipment to enable them to take into account the movement of the ship when they fire indirectly. It's not known if the photos of Chinese artillery firing from cargo ship decks is just an experiment or part of a project to make practice of this technique. If China were to attempt an invasion of Taiwan, this kind of improvisation would make sense. For those Chinese cargo ships that survived Taiwanese submarines, mines, aircraft and missiles, would need all the firepower they could get once they got close to shore. Taiwanese artillery, and even tanks, have been seem practice firing at floating targets just off shore.