This is one of the most common questions people ask when they see a large boat at the dock. The short answer is: it can be expensive, but the exact cost depends on fuel capacity, engine type, and current fuel prices.
For a typical 50-foot boat, filling the tank can cost anywhere from a few thousand dollars to well over $5,000 in a single fill-up.
Typical fuel capacity of a 50-foot boat
Most 50-foot boats carry between 500 and 1,000 gallons of fuel. The exact number depends on the type of boat:
- Center consoles: 600–1,000+ gallons
- Motor yachts: 500–800 gallons
- Sportfish boats: 700–1,200 gallons
Larger fuel tanks allow for longer offshore runs, but they also mean higher fill-up costs.
Fuel price makes a big difference
Marine fuel prices vary by location, but in places like Florida, diesel or gasoline at marinas typically ranges from $4 to $7 per gallon.
Using those numbers, here’s what a full tank looks like:
- 500 gallons: $2,000 – $3,500
- 800 gallons: $3,200 – $5,600
- 1,000 gallons: $4,000 – $7,000
Real-world example
If you have a 50-foot center console with an 800-gallon tank and fuel costs $5.50 per gallon, a full fill-up would cost:
800 × $5.50 = $4,400
That’s for one fill. Many owners do not run the tank empty each trip, but even partial refuels can still cost thousands.
How quickly does a 50-foot boat burn fuel?
Fuel burn depends on engines and speed, but a 50-foot boat can easily burn:
- 40–80 gallons per hour at cruising speed
- 100+ gallons per hour at high speed
That means a long day offshore can burn hundreds of gallons, which adds up quickly at marina fuel prices.
Why marina fuel is more expensive
Fuel at marinas costs more than at gas stations due to transportation, storage, and waterfront operations. Convenience also plays a role, since fueling happens directly at the dock.
Ways owners manage fuel costs
Experienced boaters often take steps to reduce fuel expenses:
- Cruising at efficient speeds instead of wide-open throttle
- Planning routes to minimize unnecessary running
- Refueling before tanks are completely empty
- Using fuel docks with lower pricing when available
Is it always this expensive?
Not every outing requires a full tank. Many owners top off fuel gradually, depending on usage. However, when it’s time to fully refuel, the cost can still come as a shock to new buyers.
Final thoughts
Filling up a 50-foot boat is not cheap. Most owners should expect to spend anywhere from $3,000 to $6,000+ per full tank, depending on fuel capacity and prices.
Fuel is one of the biggest ongoing costs of boating, and understanding it upfront helps set realistic expectations before stepping into ownership.
