Attwood's shower sump systems deliver the performance you've been asking for. Standard Box size that offers fast water flow into and out of sump. The lid snaps in to allow quick installation (and removal for cleaning) and includes a gasket to seal the sump box against overflow. The sump box even includes an air to prevent air locks. Meets or exceeds all applicable of the ABYC and USCG.
Standard Box Size
Gallons Per Hour = 500 GPH | Gallons Per Minute = NONE | Operation = Automatic | Outlet Size = 3/4" | Power - Max Continuous (Amps) = 1.5 amp | Volts = 12v