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What is the Best Way to Avoid Running Aground?

Fact checked by William Hart

what is the best way to avoid running aground

Running aground is one of the most common accidents in the world of boating, ranked only after ship-on-ship collisions. Most of the time, it only brings embarrassment and small damages. But in severe cases, it might result in total loss of the vessel and even human casualties.

The key to avoiding a ship running aground is to know your boat’s draft, estimate the water underneath your vessel (do so by reading nautical charts, calculating tidal fluctuation, and observing the water color changes), and use the help of a depth finder. You can also practice maneuvering your boat near sandy shoals.

Knowing the answer to “What is the best way to avoid running aground” will save you from costly and awkward moments. So, keep reading for explanations of each method.

Table of Contents

What Does Running Aground Mean?


1. Definition

Boat running aground happens when the water is not deep enough to keep the vessel afloat, making it impossible to drive the boat out of its stuck position. The situation can be referred to as ship grounding or ship stranding.

Sometimes, operators do this intentionally for ship maintenance or cargo landing. But it might happen as accident and require external help if the operator can’t handle the situation.

2. Causes

What are the causes? Such accidents occur due to tidal fluctuations, shifts in markers, and changes in the bottom structures of the waterway. There are multiple reasons and excuses, but it is the operator’s misjudgment of the water depths.

In the second part of this article, we will guide you to estimate the water level of the area you are heading towards.

3. Potential damages

In most cases, running aground only causes damage to the hull. Since modern ships are usually made from lighter and more flexible materials, you might see larger proportions of damage. But they are less expensive and time-consuming to repair.

In more serious cases, the damage might be irreversible. If your inboard/outboard boat runs aground, while navigating at high speed, the accident might lead to total loss of the vessel and even human casualties.

The Best Measures to Avoid Running Aground

Running aground might happen to everyone, but you can reduce the damage when knowing the best measures against it. Here are a few.

1. Calculate your boat’s draft beforehand

What should you do to prevent running aground in the first place? Calculate your boat’s draft!

Knowing how far your keel extends under the water is key to staying afloat. Most manufacturers publish boat draft measurements. But if yours don’t, grab a measuring tape and do it yourself.

You should measure vertically from the lowest point of the boat’s bottom to the waterline. Whenever you need, compare this number with the water depth provided on nautical charts. If the number is lower than the water level, your boat will get stranded on that water body.

  • Note: Weight can fluctuate a boat’s draft. Extra passengers or a full load of gear and fuel will increase your boat’s draft by one to several inches. Bear this in mind so you’ll never misestimate and run aground.

2. Make use of nautical charts


Nautical charts are fundamental to avoiding boating accidents. They use a system of navigational aids to notify boaters about water depths, threats, safe water bodies, and regulations. To steer clear of shallow waters, look for the hazard, cardinal, and lateral markers.

On the map, hazard non-lateral aids are presented by diamond shapes with a cross. On the water, they are white markers with orange diamonds and black lettering. These aids inform you about shallow banks, rocky bottoms, floating objects – anything that might get your boat stranded.

Other than that, keep an eye out for cardinal and lateral markers. Cardinal marks have distinctive black and yellow markings, while lateral aids are red and green. They all indicate the safe sides you should pass on.

Since natural causes can shift the positions of navigational aids, make sure you have an up-to-date chart. In addition, maintain a sharp lookout for any unusual occurrences. Before you navigate unfamiliar waters, prepare by learning the area’s chart.

3. Be careful of tidal water


Take the tides into account whenever you travel in tidal water.

A tidal coast usually has two higher-water and two lower-water levels each day. The water depths you see on nautical charts are MLW (mean low of the lower water), which indicates the lowest water level on average.

The actual depth will be the MLW plus the height of the wave at that time. Thus, it is generally safe to navigate the water if your boat’s draft measurement is less than the water depth provided by charts. Remember to proceed with cautions, though.

On what occasions do you need to be cautious? Safely passing a tidal waterway early in the morning doesn’t mean you can do the same in the afternoon. Don’t assume that the water won’t change much. The most reliable fact to count on is comparing the map’s figure and your boat’s draft.

Additionally, don’t dock your boat on falling tides. Try resisting the attempt to beach your boat and discover a remote landmass. As the tides start to go out, your boat will be left stranded. If you are lucky, the water might rise a couple of hours later. But in other cases, you will have to call for help or wait overnight.

4. Keep a sharp lookout for color changes in the water


Most running aground accidents happen on calm and clear days when it is supposed to be safe. Thus, always operate a vessel with caution and thoughtfulness. Besides keeping an eye out for buoys and markers, you should notice any color changes in the water.

Deep waters look darker than shallow waters, sandy shoals can look like bright white spots, and shallow weed beds appear in dark green colors. The key is to look for any unusual changes.

Try to avoid abnormal areas. Sticking to water bodies with the same color means staying in the same depth range. Also, keep your eyes peeled for waves that break in one spot over and over. The phenomenon indicates shallow bars.

5. Install a depth finder


Maps can not keep up with constant changes in the water, and observations can fool you, but a depth finder is a device you can trust. It does exactly what its name says – find and display water’s depth information.

However, learn how your finder is calibrated. Does it measure from the device or from the lowest point of your boat to the seabed? Make sure you understand its functions thoroughly. Misinterpreting information on depth finders can lead you straight into trouble.

Another excellent feature of these devices is the ability to alert you when they find the bottom too close. You can set the statistical point when you want the alarm to go off. You can even turn off the alarm if you want to.

6. Practice maneuvering your boat skillfully


“Operating a boat” and “operating a boat skillfully and mindfully” are two different terms. Captains who wander on shallow waters regularly need to sharpen their boating skills.

What action should you take? The most important skill is to learn when to stop your vessel. Should you attempt to go a bit more to pass a shallow area, possibly, or should you quickly stop and reverse your vessel to find a detour? I bet we all know the latter is the safer choice.

You should also learn how to brake quickly and safely. Like driving a car, you must stay calm and react smartly to incidents. Practice several times and see how long it takes for your vessel to stop completely while going at different speeds.

Whenever you travel near sandy banks, put your vessel at idle speed so you can stop it in time. Doing so will help reduce the damage in unfortunate events.

Besides, you might be tempted to trim the outdrive as far up as possible to travel faster and more smoothly, but don’t do so in shallow waters. Leave it a few inches down, so you can tilt it up a little to find room to back off the vessel in the worst-case scenario.


All in all, boat stranding can be avoided by understanding your boat’s draft, knowing how to use the nautical chart effectively, being aware of tidal waves and color changes in the water, installing a depth finder, and sharpening your boating skills.

We hope the six methods provided help you answer the question “What is the best way to avoid running aground” clearly. Now, feel free to explore a new waterway, go hunting for the rare fish that only lives in those shallow banks, and discover a remote island on which just a few people have set foot.

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