There is the danger of accumulated fumes catching fire if there is a spark when an electrical device is switched on.
A huge explosion.
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.
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.
Gas fumes will stay in the bottom of the boat.
check the tank
Ventilate the engine compartment, if enclosed.
An important step when refueling a boat is ensuring electrical switches are off.
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.
closing all hatches and doors while refueling
A blower should be operated in a boat before starting the engine and periodically while the engine is running, especially if the boat has an enclosed engine compartment. This helps to ventilate any potentially hazardous fumes or gases, such as gasoline vapors, which can accumulate and pose a risk of explosion. Additionally, it's good practice to run the blower for a few minutes after refueling to ensure that any residual vapors are cleared. Always check the manufacturer's guidelines for specific recommendations related to your boat.
Fuel vapours will linger in the cabin