How Shallow Can a Jet Ski Run?

Jet skiing is one of my favorite ways to spend hours in the water. From high speed runs to exploring backwaters, jet skis can do it all. People use them to fish areas not accessible by bigger boats or from shores. But you have to careful where you take your jet ski to avoid damage.

Jet ski engines should not be ran in depths less than two to three feet to prevent debris from being sucked into the impeller and pump, possibly causing serious damage.Jet skis can float with engine off in as little as 6 inches, but you risk hull scratches.

Remember, jet skis are propelled by powerfully sucking in water and then jetting it out. That vacuum effect can pull in a lot more than just water. Even large rocks can be sucked in. Using some simple prep and knowledge, you can avoid common mistakes that could end up costing you a lot of money.

Jet skis need to avoid shallow water less than 3 feet deep

Getting Started

You’ve just bought your first jet ski. You can’t wait to get it into the water. You’ve purchased accessories, a matching lifejacket, and have it loaded up on your trailer to head to the water. But have you done your research? Do you know what areas to steer clear of, or how to deal with shallow water?

Personal watercraft are different from a lot of other watercraft because they do not have an exposed prop. While that has its benefits, it also means that we must be more careful with the depth of water we use it in.

Because there is no prop or engine exposed, they are easier to use in shallow water. A jet ski won’t get caught on anything or damage the prop on a reef or stone. But the pump can quickly become flooded with unwanted debris, and that debris can damage the engine. And shallow obstacles can scratch or even crack the hull.

When that engine gets fired up, water gets sucked into the pump after the impeller begins spinning. The suction is extremely powerful, so if you are in shallow water, it won’t take long before the pump begins drawing in lots of debris such as sand, mud, stones, or shells. Or really, anything on the floor of the water.

All PWC’s have an intake grate cover that prevents some large objects from entering. But the flow of water cannot be restricted by anything, or the ski‘s performance will be hampered and the engine may overheat.

So these intake grates are not made of fine mesh. The openings have to be large enough to provide power and engine cooling. See Why Jet Skis Overheat and What to Do About It.

This means pretty significant debris can get past the grate. In our second year of ownership, our marina reinforced the bank behind our jet docks with gravel under the waterline. We did not know this. The result was a new pump, wear ring and impeller for the RXP-X. Ouch!

Consider all the elements you’ll be facing and make sure you know what to avoid and how to prepare for a fun day out on the water.  Not treating your ski correctly can ruin the fun. If you are taking a long trip to an unfamiliar area, trailer prep is important. But you also need to scout out the riding zones and keep an eye out for sudden depth changes.

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How to Approach Your Day on the Water

Part of the fun of a personal watercraft is the freedom to use it in many different types of water. In addition, they are often easier to transport than a boat, and faster and more maneuverable.  Plus, their smaller size makes for more storage flexibility.  And learning to use one is easy. Many serious fishermen are using jet skis to fish (my post) so they can access tighter areas and shallow waters that have no land access and that boats can’t reach.

Keeping in mind these items will ensure a fun day on the water.

Body of Water and its Floor

Depending on the type of water you’re in, you may have more or less than you need to worry about. Think about the difference on the floor of the body of water you’re in. They will bring different elements that will influence your personal watercraft.

  • Rivers: When out on a river, you have a lot of additional debris to consider. Think of what riverbeds have a lot more of than a river or lake:
  • Mud
    • Sticks
    • Stones
    • Grass
    • Small creatures
    • Leaves

It can end up being a little trickier when you get to shallow water, solely because there are a lot of things that the pump could suck up. Whether you are out there for fishing, a joy ride, or taking in some of the sights, you will want to be sure you steer clear of the edges of the riverbed where it will get shallower.

You’ll have better chances of getting unwanted debris stuck in your pump if you drift along the edges. Be especially careful if you are out there fishing, because it is easy to drift and not pay attention to how far you’ve gone.

  • Lakes: Lakes can have very similar conditions to a river to consider. Whether there is sand or mud at the bottom, there tends to be more flora in lakes and rivers than you deal with out on the ocean. 

If you’re go-to body of water is going to be a lake, it is essential to know what the surface is like under the water, and make sure that as you launch or head back, you’re allowing it to idle when you get to the shoreline. 

Grass and sand won’t cause too much of an issue, as long as you don’t let it continue to happen. But the plastic trash, twigs, and rocks are where you need to be careful.

  • Oceans: One advantage of being in a large body of water is helping to cleanse the pump if something does get sucked up in there. When you launch, if you notice some debris has gotten sucked up, you can literally just flush it out when you’re out on open water. If you push your RPM’s higher and let it run cleanly in that deeper water for a while, it should help to clear anything that was stuck in there. 

But on the flip side, you need to be aware of sand bars. Know the area you are going to be in, and if there are any spots that may have higher sand bars that could affect your ride. 

The other element to be aware of in the ocean is going to be seaweed. Like grass, it won’t usually cause a significant problem. But since it has a tendency to tangle more than grass, it still has the potential to become a problem.

No matter the body of water, just make sure you are aware of your surroundings and try to flush anything out right away that has been sucked into the pump. Whenever you can get in or out of the water on a dock, take that opportunity. Being able to start and finish in deeper water helps a great deal. Just be extra careful to not ding or scratch your jet ski on the dock.

What if my jet ski sucks up trash?

If you know that you’ve ridden your PWC or jet ski over possible debris, your jet ski is bogging down or you feel a vibration, quickly glance around to make sure you’re in a safe area, then shut off the motor immediately. Follow these steps to try and clear the object or material.

  • Remove the key from the ignition
  • Rock your jet ski from side to side quickly several times
  • Restart the motor and listen for any signs of pump blockage such as rattles or abnormal tone
  • If all sounds good, give it some throttle and listen to the engine noise. If all seems OK, accelerate to see if performance is normal
  • If the PWC bogs down, it doesn’t sound right or you feel a vibration, shut it down again
  • If possible, move your jet ski to a safe dock or shore area to check
  • If water is clear, you may be able to visually inspect the intake. Look behind the grill on the bottom rear. Clear any visible debris and try again
  • Don’t jam any tool or stick into the intake to dislodge an object, as you may damage the impeller prop or surrounding wear ring, which will degrade performance or even require replacement
  • If your PWC still acts or sounds like it has a problem, you may need to pull it out and reinspect. Your trailer can help here
  • If the problem still persists, you’ll either need to take it back to your garage or to your preferred shop
7/26/2020. Not our rope. No idea how we picked it up.

We recently noticed a slight reduction in top speed of the RXT 260 after a lake trip away from home. No real hesitation or bogging down. No error codes or vibration. But I thought I’d check anyway. Found the above tow rope wrapped around the impeller shaft.

It isn’t ours, which are all red or blue, and we haven’t towed with that ski for 2 years. I have no idea where it came from. I used a thin pair of scissors to cut it away in layers because I couldn’t get my knife in there. It took 5 minutes.

I’ll need to check the pump at some point in case small pieces were sucked in. Moral of the story, inspect everything regularly.

Other Factors to Consider

When you understand how your jet ski operates, and you take into consideration all of the safety aspects, you will always be able to have more fun. It will become second nature that you take these things into account so you can let go and have a great time. 

  • Speed – if you’re in shallow water, keep it slow so that the pump doesn’t overwork itself and suck everything in. Wait until you’re in 3 feet of water before starting and running your ski.
  • Tips on flushing the pump – Lift the stern several times, going up and down, to flush the pump after you get it off the beach. This will help remove excess dirt and sand.

The Personal Watercraft Industry Association has some great tips on water safety and things to consider when you’re out on the water. While the depth of the water is an important consideration, there are also other elements you should be aware of before taking your jet ski out.

Hit the Water

Avoiding common errors made by many new users will help ensure a fun day out on the water for you. Know the area (on the surface and underneath), be aware of the conditions, and make sure to keep that pump free and clear of debris, and you will be ready for a fun-filled day on your jet ski.

Tim Conner, M.D.

Tim Conner, M.D. started boating in 1974. He has been involved in recreational boating continuously since then. Dr. Conner has been active in boating and watersports safety education for decades. He rode his first jet ski in 1997, and rejoined the personal watercraft arena in 2012 with a Sea-Doo GTX 155, followed by 2 supercharged SeaDoos. Scuba certification came in 1988, and he and the family have traveled the world snorkeling and scuba diving for decades. The family has recently taken up paddle boarding. Click the photo for a lot more.

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You need to be aware of the depth and type of water in which you're operating a jet ski.  When riding a PWC in shallow water, keep it slow to avoid sucking objects into the pump.