Access to OB sanitary discharge valve

[CC-25 Ray]

While replacing the Y valve and several hosed on my older Carolina Classic 25 sanitary waste system I thought I might as well check the hose condition and connection to the OB discharge hull connector; however I couldn't determine how to access this connection. My sanitary system OB discharge hull connection is located outboard of the waste hold-up tank on the port side, midships at or just above the water line.
Is this hull connector equipped with an isolation valve? Any advice appreciated .