Modern weapons on a Roman quinquereme

How would you refit a Roman quinquereme with modern weapons for ancient or modern combat?

Arm the crew with modern portable weapons and fit light cannon or heavy machine guns that the wooden hull can support without overloading it.

Modern small arms and shoulder-fired weapons offer the easiest way to increase a quinquereme's firepower without rebuilding the vessel. Portable weapons also suit the close fighting of ancient naval battles. A 20 mm cannon could replace some ancient deck artillery, while M2 Browning heavy machine guns would threaten wooden hulls and the crews behind them. Their comparatively manageable recoil makes them more plausible fittings than an octuple pom-pom mount, which is rejected as too heavy. Suggestions also include a Carl Gustaf recoilless weapon and Mark 19 grenade launchers, although the latter receives an explicit qualification about limited familiarity. The choice therefore depends on the wooden structure's ability to carry the mount and absorb its loads.