On 505 we have the off shore plug in as water can get down below when the bow dips into short steep waves. Salt water managed to get into some of my wire connections for the nav lights. good to replace those wires every 25 years.
The dorade is same, same as the engine air ventilation ones on the stern -- one faces forward and one faces back.
the forward one connected to a dryer hose goes to the bottom of the engine compartment and the back one goes to the top of the engine compartment. at least that's how it works on the 500 series.
