So I've been doing a little research as i'm considering trying to write an alternative history novel in which Carausius' independent romano-britain survives. In doing so I've been researching the late Roman navy but most of the information I've found seems to be focused on earlier periods. Did the Roman's continue to favour boarding actions? How extensive was the use of ship mounted artillery and if so what kinds of engines and ammunition was most common? How important was archers, slingers, javelins throwers ect? How might the roman navy developed had it lasted longer and had maintained a reasonable amount of funding.