Eye-Opening Facts About the Cost of Boat Gas

How Much Does Boat Gas Cost?

Boating is one of America’s favorite pastimes, with over 87 million people participating at least once a year. There are nearly 12 million registered boats in the country. That makes the question of the cost of fuel a vital one.

Factors Affecting the Cost

Several elements come into play when you try to determine the cost of fuel. They include:

  • Location
  • Type of gas
  • Octane rating
  • Kind of boat
  • Cruising speed

Most boats are of a tailorable size under 26 feet. That means a lot of people are getting them fueled up at their local gas station—probably when they’re getting gas for their vehicle too. Others who have their vessel at the dock at their house or marina often get cans to bring back and get the job done. They also pay the same price

That takes the mystery out of what it costs in some cases. But it doesn’t tell the entire story.

Many choose to buy fuel on the water at a gas dock or marina. And what you dish out for the convenience and full service factors into the price per gallon. Depending on where you live, you may end up paying 50 percent or more.

You have to remember that marinas and anything boat-related are seasonal businesses. So, prices are naturally going to be higher. But it’s not the only thing affecting what you pay at the pump.

Type of Gas

Your boat likely takes gasoline instead of diesel. Most vessels over 45 feet run better and more efficiently. There is one other point to consider, oxygenated versus non-oxygenated.

The former has ethanol in it. It may also contain other additives. The purpose is to reduce carbon monoxide emissions. The latter is the opposite. It can burn less clean, but it cuts down on corrosion.

That’s a big deal if you have an older boat because it’s better to use non-oxygenated. It also means you’re going to pay more. You can expect to see run $0.10 or more per gallon. And not every station carries it either. You’ll need to do some research to find one near you.

Speaking of older boats, there’s another point you must weigh when considering the cost of boat gas—lead.

Of course, you’re not going to get it at your local BP. However, you will need to add a lead substitute to your fuel tank or risk having to rebuild the cylinder heads. It might sway you to think about new boat prices.

Octane Rating

You’ll find that boats aren’t a lot different than cars when it comes to the octane rating. You’ll see a recommended figure from the manufacturer. That’s the gas you want to get. It’s a reflection of the type of engine and its compression ratio.

If you have a high-performance vessel like a speed boat or high-end fishing boat, you need to ante up for the higher octane gas for optimal operation. It typically runs about $0.02 to $0.05 per gallon more than regular.

Kind of Boat

What you take on the water also plays a role in what you’ll pay for fuel. Generally, newer boats get better gas mileage than older ones if just because of technology upgrades like fuel injection.

But, let’s be clear. Fuel economy is not a major selling factor for a boat. Water puts up a lot of resistance. It’s variable too. You won’t boat in the same water twice. And you’ll pay more for going an equal distance than you would in a car.

Calculating fuel consumption isn’t the same when you’re on the water. Instead, you determine the gallons per hour based on its horsepower and fuel type first. A quick way to figure it out is to divide your gasoline engine’s horsepower by 10.

A 250-horsepower is about 25 gallons per hour (GPH). That is at peak output and not an average of your overall boating performance. It will vary depending on your RPMs, the state of your engine, and many other factors like wind speed, waves, and even the condition of your hull. You can also use a flow meter to get a precise number.

You could drill it down to miles per hour, but it isn’t pretty. Using the example above, you get about 0.8 mph going 20 mph across the lake. Ouch!

But all isn’t lost. The trick is finding that sweet spot on your RPM dial to optimize your boat’s fuel economy and save money on gas.

Cruising Speed

Generally, the faster you go, the more fuel your boat burns. Also, heavier vessels use more just because of their size. But your optimal cruising speed puts you in the driver’s seat.

It takes some patience, but it’s worth the effort. Pay attention to your RPMs and the corresponding flow rate. For gasoline-powered boats, you’re looking at around 3,000 to 3,500.

But it also makes a difference whether you’re driving a pontoon or speed boat. With the former, you’re not breaking any records. The latter probably makes you a frequent visitor to the gas dock. It goes back to your style of boating.

Some people prefer coasting along slowly. That’s not ideal since you’ll likely spend more in the long run unless you’re a sailboat trader. Others like to skip across the water. If they’re in their RPM sweet spot, they’ll optimize their usage.

Size matters too. A yacht will measure around 20 to 30 feet, often more. The figures on fuel economy change if you push 45 feet, which brings diesel fuel to the table. The advantage that it offers is that you can plan your gas budget easier with less volatile prices.

Calculating the Cost

Let’s go back to the 250-horsepower powerboat. Let’s say you boat about once a week. You cruise for about four hours each outing. At 25 GPH, you’re using 100 gallons every time.


If you have a pontoon, the GPH is lower. Many come are around 5 GPH. That will bring your outing cost down to $65 and $260 a month. Yacht owners will see similar savings with lower prices on diesel fuel and better GPH.

The adage about the meaning of the acronym, B-O-A-T or break out another thousand, applies to the gas as well as the repairs. However, it’s hard to put a price on the enjoyment of cruising across the glass surface of a lake. It’s like going on vacation every time you go out on the water