By model year 2013 (July 1, 2012), gasoline-powered boats will incorporate more advanced fuel systems designed and tested to activate the gas pump’s automatic shutoff feature, eliminating overfilling. Though no one should leave a boat unattended while fueling, the new system takes the effort out of knowing when the boat is full. Part of this new design is a carbon canister tucked away in the boat’s vent line and packed with a special marine-grade carbon. The carbon scrubs the hydrocarbons from the fuel vapor, eliminating fuel odors and contributing to cleaner air. The components also include new fuel lines and tank-construction materials that reduce the permeation of fuel into the line and tank material.

The technology used is nothing new; the secret lies in the valves. These components are mounted on top or in the tank and are precisely calibrated to make sure the tank fills to the proper level every time. By reacting to the fuel level in the tank, the combination of valves sends liquid fuel up to the fill neck, activating the shutoff feature in the gasoline pump nozzle. Ensuring a predetermined level in the tank eliminates traditional vent leakage from the fuel expanding due to the daily temperature rise. This also protects the carbon canister located in the vent line from becoming saturated with liquid fuel. There are some cautions:

• There are no user-serviceable parts in this system. The canister and valves have a similar useful life as the ones in your car; they’re not predicted to fail over the life of the boat.
• Should a fuel system be suspected as a failure point, a qualified service technician must make the repair to ensure the integrity of the system.
• Do Not over-fill! Just like your car, this system can be overcome by repeated attempts to “top off” or using a very slow fill, such as from a jerry can. The extra gallon is not worth the risk of having liquid fuel end up in areas that weren’t designed for it. For now, these systems are not an aftermarket solution. Rigorous industry standards, coupled with extensive manufacturer testing, have created a robust, dependable system that has different characteristics based on the model of the boat.