ventilation for fuel tank, fresh water tank on the ship

ship ventilation metal boat air mushroom system housing equipment valve industrial pipeline element deck pipe pipes surface vessel protection contamination vertical circulation exhaust tube fittings cylindrical entrance hemispheres vent retarding barrier tank outlet sealed bunker ingress inflow tackle installed fresh water head securing locking fuel oil rusty control construction sea work painting metal industry boat ship steel transportation air marine repair mushroom maintenance fuel port equipment industrial shipping circular nautical labor deck pipe ventilation tank vessel ventilator hull carrier dock vertical circulation exhaust harness seaman shipbuilder ballast bulk vent bulk derust shipyard marine engineering rusty head double bottom