that the vents were originally put in to help dissipate the heat a little.
On most boats the air will circulate from the aft to the front internally. With the vents on the transom the air would go in those vents (even if they're facing aft) and come out through the gangway
, just as mine did before I fully enclosed the motor
compartment. I run a bilge
blower now with the motor
running. If it goes bad I can still pull a cover loose and go back the way it was.
Motors do tend to put off a little oil
vapor when running, even if they are new. Personally I would reinstall new vents to allow the boat to breathe. Otherwise you may start collecting a residue on the interior
and if someone were down below while motoring, the only fresh air they would get is what the motor is drawing in. Even with a front hatch
open the vapors would be working their way out that forward hatch
Putting a front scoop on the forward hatch will change the direction of flow but it will gather sea spray as well.
One big problem power boaters have is exhaust
fumes coming into the cabin
area from the rear exhaust ports
. Fortunately, sailboats are fairly aerodynamic and scoop away most of the fumes.