Securing Seas and Shores: Fleets of the Roman empire

In the usual wide ranging discussion Jasper, Michael, Lindsay and special guest Jesse Obert look at the Roman Navy. Questioning the received view of the fleets being used in anti piracy duties, and were the fleets even standing forces or more of an adhoc thing brought together when needs must?

And the fleets what kind of shipping did they comprise of, and how did they make war?