Properly fueling a boat is easy, but there are a few dos and don’ts to keep in mind. 
It may seem a bit strange at first, but learning how to fuel a boat should actually be thought of as a part of basic boating safety.
Most people will naturally associate fueling up boats with fueling up cars, but there are a number of important differences. And not only does your safety depend on a proper fueling job, the environment’s safety does, too.
Basic Boat Fueling Procedures
How you fuel your boat will vary a bit depending on what type of boat it is, and what sort of power system it has. The most critical differences? There are two. First, between boats with enclosed engine compartments or engine rooms versus those with outboards. And second, between boats with cabins and those without.
If your boat runs on diesel this is less of an issue (though it still counts) because diesel is less of a fire hazard than gas, but gas-powered boats with enclosed engine compartments are always at danger of fumes building up inside. Most manufacturers recommend you run a bilge blower not only after fueling up, but any time you start the boat after it’s been sitting for more than a few minutes. So if your boat is equipped with a blower, be sure to use it immediately after fueling and prior to turning the ignition key. With outboard boats, since there’s no enclosed engine compartment you won’t have to worry about this. 
On boats with cabins, you should also close up all doors, ports, and hatches prior to fueling. This will help prevent fumes from becoming trapped in the enclosed spaces. After fueling, open up the cabin and give it a “sniff test” to make sure your nose doesn’t detect any fumes. If your boat doesn’t have a cabin, again, you don’t have to worry about the issue.
Aside from those finer points, the basic fueling process is fairly straightforward:
- Double-check the dock lines to make sure they’re properly attached and the boat is secure.
- Remove the fill cap.
- Put the nozzle into the fuel fill.
- Pull and hold the trigger mechanism to keep the fuel flowing.
- Stop adding fuel when the tank is full.
- Replace the fill cap and secure it tightly.
What NOT to do When Fueling Your Boat
Whenever you’re fueling your boat up on the water it’s important to remember that preventing the spilling of unburned fuel is critical. Any fuel spill that leaves a sheen on the water must, by law, be reported to the US Coast Guard via the National Response Center at 800-424-8802.
There are several ways you can minimize the chances of a spill while fueling:
- First, note that fuel pumps at marinas don’t lock in the “on” position as they do at gas stations on land, but must be manually held in place the entire time you’re fueling the boat. This is so you can respond immediately if any fuel does begin to spill, so whatever you do, don’t prop the pump’s trigger mechanism on.
- Secondly, place an absorbent cloth or “fuel diaper” next to the fuel fill while adding fuel to the tanks.
- And third, stop short of filling the tanks all the way up and never try to top them off. With many boats you can hear the fuel gurgling up shortly before the tank is full and if this is true on your boat, the moment you hear it gurgle it’s a good idea to go ahead and shut off the pump.
Another common issue you’ll want to prevent is putting the fuel into the wrong fill. On most modern boats the fuel fills are clearly marked, but sometimes the difference between the fuel fill and the water tank isn’t entirely obvious. And more than one careless boater has pumped fuel right onto the deck after accidentally placing the pump nozzle into a fishing rod holder.
One final tip: always be very careful to add the appropriate fuel to your boat. If you’re not entirely sure what type of fuel to use in your boat, see Choosing the Right Fuel and Oil for Your Marine Engine.
