Recreational Boating Safety – Out of Fuel

Bob Currie
By Bob Currie, Recreational Boating Safety Specialist
U. S. Coast Guard Auxiliary Station Galveston Flotilla
I was sitting around the house Friday evening when our Auxiliary Sector Coordinator (ASC) sent me a text regarding a disabled pontoon boat in Galveston East Bay. It was a standard Search and Rescue text alert that read:

SAR – Disabled 16’ Pontoon boat- Siever’s Cut- INITIAL.

SCC received a report of a disabled 16’ pontoon boat IVO Siever’s Cut with 4 POB. Vessel is at anchor and out of gas. No medical concerns, no food or water on board. Owner/operator denied commercial assistance. MARB issued, SMC briefed. Case Pends. SCC Sends.

The Station Galveston Flotilla of the US Coast Guard Auxiliary operates out of the USCG Station Galveston base on Galveston Island. They aid the Coast Guard by providing maritime observation patrols in Galveston Bay; by providing recreational boating vessel safety checks; and by working alongside Coast Guard members in maritime accident investigation, small boat training, providing a safety zone, Aids to Navigation verification, in the galley, and watch standing.

“SAR” is “Search and Rescue.” “SCC” is “Sector Command Center.” “IVO” is “in view of.” “POB” is “persons on board.” “MARB” is Maritime Assistance Request Bulletin.” “SMC” is SAR Mission Coordinator.” The ASC asked if it was one of my neighbors. I said it could be and asked him to send me a contact name. From the text I knew that the owner had been denied commercial assistance and if they were in view of Siever’s Cut they would be easy to reach. He replied that a Good Samaritan had come to their rescue, so I didn’t need to help. Why was the boat owner denied commercial assistance? He was probably denied assistance because he wasn’t willing to pay the stiff rescue fee. I recommend having boat towing insurance for situations like this. There are two commercial towing companies in the area. Talk to them and find which one is closer to the area in which you normally operate.

Rule of Thirds
The owner operator of the pontoon boat violated one of the most important rules of the sea. He didn’t make sure he had enough fuel to get to his destination. The Coast Guard recommends that you follow the rule of thirds, which states that you should burn no more than one third of your fuel going out, use one third to get back, and save one third for reserve. If your destination from Point A is Point B, rather than a round trip from Point A to Point B and return, then the goal is to have one third of your fuel capacity left when you get to Point B. The fact is you almost always use more fuel coming back to land than you do going out. The prevailing winds are seaward from shore, so you usually have a tail wind helping you going out, and you must fight the wind to get back in. If you use half your tank going out as this operator obviously did, you are not going to make it back to the dock unless you take some measures to reduce fuel consumption. The way to do that is simply to slow down. Fuel consumption rate is directly related to speed. The faster you go, the greater your consumption rate. A boat operator needs to know his average fuel consumption based on RPM. It is easy to do. One simple way is to look it up on the internet. Once you have the GPH (gallons per hour) for a full range of RPMs, you can create a speed table. For instance, I know that with my boat and motor combination I burn 1.0 GPH at 2,000 RPM, 2.6 GPH at 3,000 RPM, 4.6 GPH at 4,000 RPM, 6.4 GPH at 5,000 RPM, and 9.7 GPH at 6,000 RPM. You can find the fuel consumption rates for your engine as well by going to

Next, you find out how fast you are running at those RPM with an average load and full fuel tank. My RPM table looks something like the table below. I added a fuel consumption hypothetical for a 20-mile run back to the dock.

It is obvious from the fuel consumption table that you sacrifice fuel efficiency for speed. Notice that my increase in speed with increase in RPM is not perfectly linear. If the speed vs. RPM rates were linear, I would be moving 60 mph at 6,000 RPM. Using this table, you can determine a speed that will get you back to the dock with the least amount of fuel required. This does not take into account fighting a headwind or heavier seas coming back to the dock. Of course it was smooth going out and rough coming back in. That is the way sea weather works. The different heating rates of water and land create winds that push seaward, and those winds kick up the waves.

Effect of Trim
The trim of your engine is another variable in the fuel consumption estimate. My table is based on moderate trim rather than full trim. Your boat does not handle chop well with full trim, so you need to use moderate trim when creating your fuel consumption table. As you trim your boat up, fuel consumption rate usually decreases, but trimming your boat up fully in choppy water reduces your stability to the point you could capsize or swap ends. End swapping occurs when a chine digs in at a time when the boat is not fully horizontal and is balanced on the tail instead. Older model tunnel boats are the most likely to swap ends when they become unstable. Either situation always leads to ejection of passengers and increases the likelihood of death or injuries as a result.

Food and Water
Don’t leave home without it. As the boat operator, you are responsible for the safety and well-being of your passengers. Don’t get caught out there without having food and water aboard. I always have plenty of energy bars on board, and lots of bottled water. You never know when you may become stranded. You should have enough food and water for 24 hours for each person on board.

When planning a trip on the water, be sure to follow the Rule of Thirds as recommended by the Coast Guard. Know your boat and engine’s fuel consumption rate, and prepare a fuel consumption table to help take the guess work out of your planning. If you do get caught short on fuel, notify the Coast Guard immediately, and keep them up to date on your progress back to shore. Slow down to a point where fuel consumption is as its best, and you will stand a good chance of getting back in.

For more information on boating safety, please visit the Official Website of the U.S. Coast Guard’s Boating Safety Division at Questions about the US Coast Guard Auxiliary or our free Vessel Safety Check program may be directed to me at [email protected] I am available to perform free Vessel Safety Checks, and I will come to your location to perform them. SAFE BOATING!


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