Ah Slimmy. You are beginning to sound like a land lubber. The exhaust fan  is 
called a bilge exhaust fan. I run it on the Chris Craft for several minutes  
prior to hitting the starter key. You do this to eliminate any gas fumes in 
the  engine compartment. Since the engine on the R22 is hanging on the stern, 
why  install an exhaust fan?
Did I start this.....again?
 
 
Rummy