If you do not ventilate your boat after feeling, moisture and humidity can build up, leading to mold and mildew growth, which can damage the interior and create unhealthy air quality. Additionally, stagnant air can result in unpleasant odors and can cause corrosion of metal components. Proper ventilation is essential for maintaining a safe and comfortable environment on board.
A huge explosion.
There is the danger of accumulated fumes catching fire if there is a spark when an electrical device is switched on.
You have a high risk of blowing up you boat.
There will certainly be vapour from the fuel present and lighting of any naked flame could cause an explosion of this vapour.
If you do not ventilate your boat after fueling, harmful vapors may accumulate in the confined spaces, increasing the risk of fire or explosion. These fumes are flammable and can create a dangerous environment for anyone on board. Additionally, poor ventilation can lead to carbon monoxide buildup, which poses serious health risks. Properly ventilating the boat helps ensure safety and reduces the likelihood of accidents.
You need to ventilate your boat after refueling to disperse any build-up of flammable fumes - especially petrol (diesel is less dangerous). Any petrol fumes sinking into the bilges could be ignited by a spark from an electrical switch, or when smoking.
Gas fumes will stay in the bottom of the boat.
Ventilate the engine compartment, if enclosed.
Gasoline and propane fumes are most likely to accumulate in the bilge of a boat, which is the lowest compartment of the hull where water collects. It is important to regularly inspect and properly ventilate the bilge to prevent the build-up of flammable vapors.
Fuel vapours will linger in the cabin
Fuel vapours will linger in the cabin
Unusually nothing happens. BUT a build-up of fumes is possible under the right conditions. That along with an ignition source (engine starter motor etc..) can cause a catastrophic explosion. Use the blower while fueling and before starts IAW your owners manual.