The fuel tank area on my boat has clear opening where the fuel lines and wires pass over bulkheads into the bilge plus area around the sides where the vent an fill lines pass through, plenty of area for air to move.
Since I installed that vent, the small standing water that collects in the bilge evaporates after a few days, so I would say a win win over just letting the deck plate leak.
the picture - that's the fuel cell area on a parker...note the foam on both side of the stringers ?? the deck sits on those stringers...the aft bulkhead is indeed cut,to allow fuel lines to pass - the bulkhead's plywood,the hole isn't sealed,it's drilled through with a small hole saw - no chafe protection either...
that fuel cell area,it's sealed,meaning,if water leaks through either one of the deck plates on the deck,that water remains in that area - deck plates leak...take note of that picture - the "grey areas" - that's foam,which was supporting the tanks,and the grey,is the cheap enamel paint the tank manufacture uses on the tank's surface...
that's water,water that's leaked in the area through the deck plates - the foam that was surrounding the tank,it's been removed to allow removal of the tank - that foam was completely waterlogged...the boat,it's was sitting on land for approx. 5yrs,before I began repairing the structural problems - dry rotted stringers,dry rotted decking,dry rotted bulkheads,you get the picture here,yes ??
will ventilation help ?? it can't hurt...but,will it dry the entire area ?? you tell me

that's basically a sealed area,not much of an air flow is gonna take place in there,and,as far as the bilge is concerned,only opening is a hole approx. 1- 1 1/4" diameter,that connects the bilge to the tank cell area...
this is the third parker I've cut apart to perform major structural repairs to - everyone,has had similar poor construction techniques used by the factory - including the use of iron nails holding unprotected plywood together...
I believe you follow my business facebook page,yes ?? you've seen the pictures,and I believe you made a few comments on them,yes ??
sorry for the side track here guys...
