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5 Small Things You Can Do to Improve Fuel Economy

By: Craig Ritchie

One of the greatest things about boating is that it’s an affordable family activity everyone can enjoy. Still, no one wants to spend more money than they have to, and that’s especially true when it comes time to gas up. Fortunately, saving money by reducing your fuel bills is actually pretty easy. Just try these proven tips from the pros.

Learn To Trim Your Boat

There’s no doubt about it – learning how to properly trim the boat can go a long way toward reducing those fuel bills.

Proper trim is all about having the right attitude – and we mean the boat’s attitude, not yours. The idea is to have the bottom of the boat running parallel with the water surface so that you maximize engine thrust and reduce drag. Running the boat with the bow too high or too low increases drag – both in the air and in the water – which means your engine has to burn more fuel than necessary.

Trim is normally adjusted by a small toggle switch that’s usually mounted on the side of the throttle lever, where it can be easily controlled by your thumb. As the boat accelerates onto plane, gently touching the trim switch up or down will alternately raise or lower the bow, allowing you to ensure the boat runs nice and level for optimal fuel economy and a more comfortable ride.

Boat planing on lake
A well trimmed boat

Throttle Back

It’s fun to go fast in the boat, and there are times when speed can be beneficial. But running the boat at full throttle all the time gets to be awfully expensive. Even throttling back just a little now and then can save a surprising amount of fuel.

In one study with a 40-foot cruiser,researchers found that throttling back by just 600 rpm cut fuel consumption by an astonishing 45 percent! Better yet, it only reduced the boat’s speed by a little over 5 mph – a drop that would be hardly noticeable to anyone on board.

Over a full season of boating, slowing down just a little can save you an awful lot of fuel, and an awful lot of money.

Boat throttle and trim
Photo courtesy Craig Ritchie

Put The Boat On A Diet

One thing about boats is that they tend to collect a lot of stuff. All that extra gear represents extra weight that the engine has to push around, and that has an obvious impact on fuel economy. Taking a few minutes now and then to unload the stuff you don’t plan to use right away can really add up and save a surprising amount of fuel over a season.

Lightening up also applies to your fuel load. As every pilot knows, a full tank represents a lot of added weight. Do you really need it? Or will half a tank of fuel be more than enough to get you through the day? If you’re serious about reducing your fuel expenses, then lightening the load by carrying only what you really need is a great place to start.

Boat storage compartments
Photo courtesy Craig Ritchie

Keep The Engine In Tune

One of the best things you can do to reduce fuel costs is to keep your engine running like a Swiss watch. While it may cost you a few dollars each year to have a qualified marine mechanic look things over, you’ll make that investment back in fuel savings, to say nothing of reduced engine wear.

Any engine tune-up will start by replacing the filters. This can make a big difference in fuel economy and engine performance, since even a partially clogged fuel filter can make the engine work a lot harder than it needs to. Air filters are equally important, since an engine that can’t breathe is an engine that can’t run as it should. Fuel filters and air filters should be replaced every year without fail.

Technicians will also check the engine for loose belts, fouled plugs, faulty ignition timing and any other potential issues that can ultimately drive up fuel costs.

A good engine tech will also make a point of checking the propeller. Most propellers accumulate their share of small dings, dents and bends over time, and this minor damage directly reduces its efficiency. The biggest problems come from cavitation, where even tiny dings in the prop can allow air pockets to form around it as it spins, reducing its bite in the water and making the engine work harder than it needs to. Always have the prop serviced with the engine, even if you can’t recall hitting anything in the water.

Most boaters schedule this simple work over the winter, when they’re not using the boat and service technicians aren’t nearly as busy. Apart from cutting their fuel bill and prolonging the life of the engine, this service protects against unexpected breakdowns out on the water – and waiting in line to have your boat fixed at the height of the season.

Servicing marine engine
Photo courtesy Craig Ritchie

Cleanliness Counts

It seems obvious, but anything you can do to reduce drag will help you save fuel and lower total operating costs.

Cleaning is especially important for boats that are kept moored at a marina where they’re in the water all the time. It doesn't take long for the hull to develop an accumulation of marine growths like algae, which increase drag when underway and have a measurable impact on fuel economy. An annual hull cleaning and the use of a good anti-fouling coating will make a big difference in how much fuel you use. Don’t neglect the propeller, the shafts and the rudder either. Protecting these surfaces with an anti-fouling agent like Propspeed that is made specifically for running gear makes a real difference.

Boats that are stored on trailers can also benefit from regular hull cleaning, and perhaps the use of a bottom wax to further reduce drag. Algae, weeds, pollen and road crud from the drive to the lake will gradually accumulate on any hull, causing increase friction as the boat moves through the water. Originally developed for Americas Cup race boats, a variety of bottom waxes can now be found in just about every boat supply shop, for both fibreglass and aluminum hulls. Most are easy to apply, and improve fuel economy by making it harder for debris to adhere to the hull.

It isn’t difficult to cut your boat’s annual fuel bill by taking just a few simple steps. Not only will you save a bunch of money, but you’ll prolong the life of your boat and get even greater enjoyment out of it.

Cleaning boat hull
Photo courtesy Craig Ritchie
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