Boat grounding: How to avoid running aground

3rd December 2021 Elena Manighetti

Boat grounding: How to avoid running aground

A popular saying, especially among sailors, is: “There are two kinds of boaters: those who have run aground, and those who will.”

A variation is: “There are two kinds of boaters: those who have run aground, and those who lie about it.” Boat groundings happen; in fact, they are fairly common. As embarrassing as it may be to ground your boat, rest assured: we have all done it, or we will, one day. It’s easy to misjudge the depth of a channel, miscalculate a tide, or drive on shifting sands unaware. All it can take is a little distraction to hit the bottom.

Soft grounding

Often, running aground in mud or sand at low speed doesn’t cause much damage. Sometimes, you can even remove yourself unassisted and go home unscathed. This is called a soft grounding.

Hard grounding

If you ground at high speed on a hard bottom, you may get stuck and the impact could leave big holes in the boat’s hull. That’s called a hard grounding. In these cases, the engine may break down and you may start taking on water. It’s also possible that the force of the crash will make people fall overboard and turn the equipment onboard into projectiles that can injure the crew. It’s extremely dangerous. 

For these reasons, you’ll want to approach shallower patches, channels, submerged rocks, and shifting sands at low speed.

How to avoid running aground

While running aground can be extremely dangerous, it’s not so difficult to avoid. The key is to stay alert and focused on driving at all times. We have some handy tips for you on the topic.

Keep a sharp lookout

As written in the COLREGs, you need to keep a close lookout while boating. This means having a dedicated person on deck to scan the water all around you. Look out for buoys, markers, shoals, and sandbars (as well as other boats). If you spot these well in time, you’ll be able to react before you get too close. 

Most boating accidents happen on a calm, clear day with light winds. This is because boaters aren’t as vigilant in favourable conditions. When you get closer to shore and busy areas, shift 100% of your attention to driving the boat.

Learn to read the water

Being able to gauge the depth of an area is essential to keeping water under your hull. For boaters who are used to motoring or sailing in the brown waters of an inland waterway or lake, it can be hard to estimate depth in clear water - the bottom can look deceivingly shallow.

There’s a handy rhyme that can help you remember what different colours mean: brown, brown, run aground; white, white, you just might; green, green, in between; blue, blue, sail on through. Having a chart on hand will help you remove any doubts. If you don’t have one, decrease the revs and avoid the area.

Check the charts often

Reading a chart is a basic skill every boater should have. Charts will alert you of most underwater dangers. Aids to Navigation will help you figure out where they are located. If you don’t carry charts (you really should), make sure to use a boating app, such as Deckee, and to learn the most important Aids to Navigation. When you see a buoy in the water, slow down immediately and check the chart. If the buoy isn’t on it, steer well away from it anyway.

Maintain a safe speed

Speed limits are in place to keep everyone on the water safe. It’s very important that you have time to act if you see an underwater hazard. For this reason, you should always follow the recommended speed limit.

Double-check tide times

Many groundings happen because of a tide miscalculation. To avoid getting stuck in the channel on the way home, make sure you double-check the tide times and review your calculations. Chances are you’ve planned to head back too late for the current conditions. You could get delayed due to strong winds or rough seas. Always review your plan at least twice.

Set a shallow-water alarm

If you have a depth sounder, you can set an alarm to go off once you reach a certain depth. Set the alarm a couple of meters above your draft. The sound will alert you, so you can slow down and scan the water nearby.

What to do if you run aground

Don’t panic and put the boat into neutral. Ask your crew if they are OK. If someone is injured, offer assistance to them first. If necessary, call the emergency services. If someone is not wearing a life jacket, ask them to put one on immediately.

Provided everyone on board is well, take the time to assess the situation. Are you taking in any water? Look at the chart - what have you likely hit? Did you misjudge the tide times? If you grounded in seagrass or coral, you’ll need to call for assistance. You could cause terrible damage and may be subject to penalties and fines.

In case you’re taking in water, you’ll need to call for help and make preparations to launch the life raft, if you have one. Don’t try to reverse off the ground - you could sink.

If you’re not taking in water and everyone is fine, lift the outboard or outdrive up to check for prop damage. In case it looks like the engine can work, turn it on and leave it in neutral. Drop the kedge anchor as far from the boat as possible - if you have a dinghy, use it. This will prevent the boat from being driven further aground.

Try to shift the weight of the boat away from where it touches the ground. To do this, ask the crew to move around the boat. If you’re alone, you may need to wait for some wave, wake, or tide action. You can use a boat hook or oar to push off the ground or you can even try to pull on the kedge anchor chain. If there are any boats around, you could contact them over the radio and ask them to give you a yank. You may need to tilt the engine upwards to move the boat.

When it feels like you’re floating, put the engine in reverse and back up very slowly. Once you’ve moved away from the area, check again for leaks. You may be able to temporarily close small cracks and holes with a wooden plug, an emergency epoxy repair kit, or an instant leak sealant. 

If you have run aground due to the tide going out, you may have to wait until there is enough water to float again. Simply check for damage and relax.

The best way to avoid a hard grounding is to keep a sharp lookout and respect the speed limits. A soft grounding at low speed doesn’t usually cause much damage and most boaters will experience it at least once in a lifetime.

Please don’t rely on the information in this article solely to go boating. Take a boat safety course or ask an experienced friend to give you private lessons before going out on your own. In some countries, you need to take a license to drive a certain size boat. Find out more in this article. Emergency services act differently around the world. Look up when and who to call for help in the country you’re boating in.


Download the Deckee app from the App Store or Google Play - it will help you prevent your boat from running aground. On the map, you will be able to view and inspect all Aids to Navigation, as well as speed limit zones. You can also log your trips, measure distances, and receive weather warnings and alerts.

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