Diesel Owners Save Big

The offshore pursuit of pelagic game fish is becoming more expensive with each passing summer. With an uncertain economy and the price of fuel climbing, many boaters are downsizing or worst yet, getting rid of their vessels altogether. But what if the passion is too great and you live and fish in a coastal region where you need a large sportfish to reach prolific offshore waters? What if you are like me and diesel practically runs through your veins?


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Based in Destin, during the summer of 2010 much of the northern Gulf was closed due to the oil spill. Since we were yearning to marlin fish, Doc Conkle, owner of the 50-foot G&S Miss Babbie, and I decided we needed to get out of the Gulf and head to The Bahamas. The game plan was to fish our way down along the east side of the closure line toward the Florida Keys. From there we would ultimately make the crossing and cruise the Old Bahama Channel to our final destination of Long Island.

If you aren't in a rush, allow some extra time to reach your destination and you will save big!

Without a time restraint the plan was to cruise at 8 knots in hopes of achieving maximum fuel efficiency. Powered by a pair of 660 HP QSM11 Cummins and a 15 kW generator, the 50-foot G&S averaged five gallons per hour at 720 rpm. That translates to only 120 gallons burned during every 24-hour period.

When I asked Buddy Gentry from G&S Boats what makes his yachts so efficient he had a few things to share. “First and foremost we keep the boats light. Secondly, prop pockets add efficiency by decreasing shaft angle. Another design criterion is weight distribution. Fuel is the main thing to worry about and ideally the fore and aft attitude of the boat should change very little regardless of the amount of fuel in the tanks.”

Buddy’s design concepts are certainly important, but when it comes to fuel efficiency they are just a few of the many influential factors that must be considered. Regardless of what boat you are running, the following recommendations for diesel operators are clearly more important now than ever before.


Diesel engines need two basic elements to operate at peak performance—clean fuel and clean air. To achieve maximum efficiency you should keep your power plants maintained above the manufacturer’s recommended schedule. I clean my air blankets and air filters every week. My dual Racor fuel/water separators are inspected daily and I replace them at the first sign of discoloration. The fact of the matter is that if you keep your filters and air intakes clean, your engines will burn less fuel.


It should come as no surprise that decreasing your load is one of the easiest ways to increase fuel efficiency. Shed some weight by eliminating unnecessary items regardless of the duration of the trip. Bring only what you really need. It will also be in your best interest to save weight by avoiding topping off your fuel tanks when you know you don’t need a full tank. Every gallon of diesel weighs approximately seven pounds. The same holds true with your water tanks, with freshwater tipping the scales at nearly eight pounds per gallon.


If you aren’t in a rush, allow extra time to reach your destination and you will save big! Let’s say your express or convertible runs at 30 knots hammers down. A 20 nautical mile run to and from your favorite stomping grounds takes about 40 minutes each way. If you burn somewhere in the neighborhood of 50 gallons per hour, at approximately $5.00/gallon, that is $500 in fuel burn and you haven’t wet a line yet. Chop the throttles down to 3/4 rack, say 24 knots, and your cruise will take 50 minutes. Ten minutes longer each way, but you only burn approximately 30 gallons per hour. The savings will add up to thousands of dollars over the course of the year for only twenty extra minutes in travel time.


There is a huge myth that you have to fish at 8 to 10 knots, have a huge boiling wake and a good wave pattern behind the boat in order to catch billfish on trolled lures. I recently modified my trolling speed from 8.5 knots down to 7 knots. I’ve shortened my spread and added a little more angle height out of my riggers. My higher speed lures still breathe and smoke at slower speeds and they still produce. Not only has my hook-up ratio increased, but I also save big at the pump.

It’s no secret that our sport is getting more and more expensive. If you are a charter captain this means passing costs off to clients or simply killing the bottom line. Remember that fuel isn’t the only expense associated with fishing and what you save on diesel you can reinvest in tackle and accessories. Please follow the aforementioned tips so today’s rising fuel costs don’t keep you off the water.

Additional Fuel Saving Tips

  • Keep your boat’s bottom clean. Unwanted marine growth zaps power and wastes fuel.
  • Use trim tabs to reduce drag and keep your boat on plane at lower RPMs.
  • The shortest distance between two points is a straight line. Even when using an autopilot check your wake to make sure you aren’t zigzagging around the ocean.
  • Save money with fuel delivery services or join a fuel membership program at your local marina.