Originally Posted by MJBrown
Brad those hoses should lead to bilge blowers mounted on the stern. Look for the vents on the stern to see where they exit. The fans should only run when the engine is on as they're there to take the heat and any fumes out of the engine compartment. Most all Beneteaus' have the same or similiar system.
(Thanks Malcome, I figured they were needed, but not sure why, since they travel through a gap that is at the bottom of the aft bulkhead where the air would have flowed in anyway.)
The big hoses go up near the holes in the "transom". So they are sucking some outside air. There is no blower on those, but there is a blower on a separate 3" diameter hose. I figure that there's enough air being consumed by the diesel that it's constantly sucking new/cool air into the engine compartment.
I haven't figured out how to turn the 3" blower on yet.
Also haven't figured out what the button is for, top center of the engine controls. It's click-on, click-off. Here's a picture, it's to the right of the battery light.
And a view behind the panel