Running and maintaining a boat requires careful budgeting. With marine fuel prices steadily increasing, it pays off to make your boat more fuel-efficient. In this article, we’ll look at ways to improve the economy of your boat’s fuel consumption, so you can save on the diesel bill.

BEFORE LEAVING THE MARINA

Before you head out on the water, there are a lot of things you can do to improve your boat’s performance.

Clean the hull

The more growth on your hull, the more drag it will have through the water. Even a few centimetres (less than an inch) of grass and barnacles can slow the boat down. Except, you’re not just travelling slower: you’re also burning more fuel. Clean your hull regularly - the warmer the water in your area, the more often you’ll need to do it.

To keep your hull smoother, consider what type of antifouling paint to applly carefully next time it’s due to be replaced.

Service your engine

A marine engine should be serviced regularly, ideally once a year. Servicing an engine is not rocket science and many boat owners can do it themselves. It’s worth going to a shop the first time, so you can observe how it’s done and how the engine runs after a proper service.

Once you’re confident you can do it, perform a full service once a year, but keep an eye regularly on:

Oil levels
Leaks
Gearbox oil
Coolant levels
The belt tension
Fuel and water filters or the carburettor
The raw seawater strainer.

Check your prop

The condition of your propeller can affect your boat’s performance. Cleaning it once a month or so will allow you to check if there is any damage.

It’s also worth investigating if your prop is the right size for your cruising speed. Most propellers are sized based on the maximum boat speed your engine can reach. Having one that’s the correct size for the speed you go at the most can help you save fuel.

Inspect fuel flow

Having a fuel-flow metre will allow you to know how many litres (gallons) of fuel you are consuming in real time. Most new boats come with a metre installed, but it’s easy to get and fix one on older boats, too. Getting real time feedback will allow you to identify potential fuel economy problems right away.

Upgrade your engine

If you’re trying to save on fuel, you may not want to invest in a new engine, but it’s worth bearing in mind that newer engines are much more fuel efficient. So when the time to upgrade comes, investing more in a more recent model, even if second-hand, might pay off in the long run.

Lighten your load

The more weight is on board, the more drag the boat will have. So leave anything you won’t need at the dock. Don’t ditch any safety equipment behind - safety first.

Ask yourself if you need to fill up all tanks for a day trip, if you’re planning to use the dinghy, and more. Once you’ve selected the gear you need to take with you, make sure to distribute the weight evenly on the vessel, so the boat is well trimmed.

Don’t warm up the engine for too long

Older engines used to take a long time to warm up. However, newer ones are ready to go in a couple of minutes. Don’t leave the engine on idle for too long - you’ll burn fuel unnecessarily.

Reduce windage

Before setting off, check the deck for any objects that may add to wind drag. For example, a bimini or a sail in a bag. Any items that can catch the wind will slow the boat down.

ON THE WATER

Once you’re out on your boat, there are some extra things you can do to keep your fuel efficiency to an optimum level.

Get on plane

Many motorboats perform better on plane, because there is less resistance under the hull. If this is the case for your boat, try to get on plane once you leave areas subject to speed limits and no-wake zones to save fuel. Do keep an eye on your wake, though - if you’re creating a big hole, you need to adjust your trim.

Trim your boat

Boat trimming involves adjusting the angle of your outboard motor or sterndrive gearcase relative to the transom. Trim is controlled by a toggle on your control lever or dash, which can be pushed up or down.

You’ll want to make sure that the prop shaft is parallel with the water surface when you’re on plane. In this position, all the propeller force pushes the boat forward, making the boat more efficient.

Slow down

On a sailboat or older powerboat, slowing down can help you save on fuel, especially in choppy seas. If you’re in no rush, you can improve your fuel economy while enjoying more time on the water with one simple change.

Plan shorter trips

An easy and quick change to make is to go on shorter boat trips. Keep close to your home port. You can stay out the whole day anyway - just drop the hook and enjoy spending time outdoors. You can fish, swim, go to shore for a walk, use your SUP or kayak, and more.

Distribute passengers well

Just like with gear, where your crew sits counts when it comes to weight distribution. Most adults weigh over 70kg (150lbs), which is a lot when it comes to boat trim. Make sure you’re trimming the boat well underway accounting for the passengers. The boat needs to sit roughly parallel to its at-rest waterline, rather than leaning on one side.

It may sound like some of this advice won’t save you much money, but savings add up. If you combine all of these tips, your boat will be as fuel-efficient as possible. Marine diesel prices may still be too high to go on a long boat trip, but you won’t be burning extra fuel unnecessarily.

HOW CAN I MAKE MY BOAT MORE FUEL EFFICIENT? BOAT FUEL SAVING TIPS