gas powered liveaboards...
You should not be smelling gasoline fumes. That is very dangerous. A proper installation of a gasoline system includes no leaks, and a passive bilge ventilation system. (An intake vent at the top of the compartment and an exhaust vent ducted to the bottom of the compartment.)
If you can smell fumes it suggests that there are leaks somewhere in your fuel system, or that your fuel tank is weeping. Either condition should be corrected.