Abstract: A marine engine exhaust system has an exhaust conduit conveying engine exhaust gas from upstream to downstream, a sensor sensing oxygen content of the exhaust gas in the conduit, and a shield located in the conduit. The shield is configured to shield the sensor from deleterious effects of liquid when liquid and exhaust gas is reverted in the exhaust conduit from downstream to upstream.

Abstract: A marine drive has a lower drive unit including a gearcase with a vertical strut having a lower horizontal torpedo with an aft propeller. An anti-ventilation plate on the strut is spaced above the torpedo. A spray shield plate on the strut is spaced above the torpedo and below the anti-ventilation plate.

Abstract: A method of setting up a reverse channel across a firewall, wherein the firewall is configured to enable entities internal to the firewall to originate connections across the firewall to entities external to the firewall but to block connections originating from entities external to the firewall, the method comprising the steps of: (a) using a server internal to the firewall to originate a connection across the firewall to a reverse channel proxy external to the firewall, the server and reverse channel proxy each having a role in relation to the connection, the server having a client role and the reverse channel proxy having a server role; and (b) initiating a role reversal process whereby the reverse channel proxy changes its role to a client role and the server changes its role to a server role.