Diesel Aspiration ?

[seayou77]

My sailboat came with a Grey 412 gas engine, now she sports a Yanmar 4JH3E, Diesel. There is a nifty box aft. of the Mizzen step, which serves to force aire into, the engine compartment as well as exhaust from the engine compartment; via two 4 inch flex. vent hoses. The thing that is nifty bout the box is that it is set with doors to secure the box for heavy weather. Note, this is a passive system.
What I'd like to do is rebuild this box such that it could be used as a deck box for storage. I would like to install a blower in one flex hose, and alow the other to remain a passive exhaust vent. Two aft. facing cowl vents, will service the dorade box.
My question is whether eliminating the passive air inlet will possibly starve the diesel engine for air? The Engine box is under the companion way ladder. The whole area under the cockpit aft. to the transome is the engine room.
Does the diesel require more airflow than the gas engine. I am of the impression that the ventillation system was to take the gas fumes out of the cabin/ engine compartment. The new engine box is being fitted with sound down insulation.
Thanks for input/opinions!

[seayou77]

Thanks Mike, I realize that turning my vents around and I'm flooding two times the four inch hose into the engine compartment. Did not consider closing any vents, just making the passive system draw air out. Considering the malaise an air starved engine can cause, I will make adjustments that flood the compartment or leave it be. The fact that the passive system could be closed off and forgotten, left a bit to be desired. Thanks for your response; I'd never thought that dry rot could be caused by an oxygen starved environment. ugly! ;)