Do jet boats use more gas?
That depends.
A lot of the information on the internet about jet boats is old or not fair comparisons. It’s in the interest of other boat manufacturers to put down jet boats as they are the competition. Jet boats have come a long way, and not enough people are making fair comparisons, so let’s do a few.
Let’s Do Comparisons
The few comparisons you do see are the ones comparing the boats on the length and not HP. It doesn’t take a rocket scientist to know a 150HP boat will use less gas than a 250HP jet boat. More HP will always use more gas no matter the boat.
But when you compare a jet boat with a similar HP engine to other boats, the fuel consumption doesn’t differ much.
For example…
A Scarab 195 250HP Jet Boat will consume 18 GPH at wide-open throttle. (link)
A MerCruiser 5.0 MPI – 305 cid at 260HP will consume 18.5 GPH at wide open throttle. (link)
A Volvo Penta 5.0 Gi – 305 cid 225HP will consume 18.2 GPH at wide open throttle. (link)
Now, let’s do a boat to boat comparison.
A Scarab 195 200HP Jet Boat will consume 16 GPH at wide-open throttle. (link)
A SEA RAY SPX 190 with a 200-HP MerCruiser 4.5L engine will consume 16.3 GPH at wide-open throttle. (here) and (here)
When you compare not only boat size but engine size, we see a jet boat is not too far off from other boats.
The Truth About Fuel Consumption
As seen from the section above, a jet boat is not too far off from other boats when you compare apples to apples.
What we really learn is that all boats suck when it comes to fuel consumption.
It requires a lot of energy to move something through the water. You can test this your self when you move your hand underwater. In comparison to running your hand in the air, running it through water is harder.
You shouldn’t only be concerning yourself with fuel consumption. Even if a jet boat did use a lot more gas, there are other things it does to make up for it.
Jet Boat Trade-Offs
I talked about this in my pros and cons of jet boats.
There are trade-offs with a jet boat that make them worth it.
Jet boats are simpler than other boats. Fewer things to go wrong and fewer things to break. This means maintenance is easier if not cheaper than other boats.
You also have the safety factor of jet boats that other boats grossly lack. For example, a jet boat doesn’t have any exposed props that could cut or hurt someone. A jet boat has it’s impeller tucked inside the boat. It’s hard to put a price on something like this as you don’t have to worry about the kids getting hurt from the exposed blade of the propeller. No matter the boat, you should have the engine off with people in the rear due to fumes and safety, but even with an engine off props are still sharp.
Jet boats are also easier to drive than other boats. Other boats use trim, and as talked about in this post, trim is to make up the shortcoming of other boats. A jet boat doesn’t need trim because it’s bow rise is almost nothing.
Not having a boat in the right trim can cause you to consume more gas too. If you’re not trimming it right, you could be using more gas than a jet boat.
Having trim on a boat is like having a manual transmission car. You need to make sure you’re in the “right gear” or the machine won’t run right. A jet boat doesn’t have trim and is more like driving an automatic car. With a jet boat, you have less to fiddle around and thus, you can spend more time having fun on the water.
Jet Boat Settings
Modern jet boats have come a long way compared to the older jet boats.
The jet boats you get today have many fuel-saving features like driving modes that other boats lack.
You don’t need full power all the time; sometimes, you just want to cruise. You can put many jet boats in an ECO mode, which cuts fuel consumption way down.
What makes these settings so interesting is the engines themselves. As talked about in my pros and cons of jet boats post, I tell you that jet boats use purpose-built marine engines. Other boats reuse engines you often find in SUVs.
Since the jet boat engine is purpose-built, they’re lighter, easier to work on, and can be tuned easier for performance or fuel saving. This is why you see driving modes more on Jet Boats and Jet Skis as the people who made the boat also made the engine. Other boat manufacturers buy truck engines and retrofit them for the marine environment.