When You See A Red Flag With A White Diagonal Stripe, Do This


Abigail ScottByAbigail Scott
Updated on 8/13/2022

Imagine yourself out on the water, relaxing in your powerboat while the sun shines and the water is at a perfect temperature. Then, suddenly, a red flag with a white diagonal stripe appears in front of you. Do you know what steps to take next?

When you are out on the water and see a red flag with a white diagonal stripe, this indicates that you are getting close to a group of scuba diving people. Be sure to slow down your boat and maintain a distance of at least 300 feet from the flag. Awareness of others around you is vital to maintaining the water's cleanliness for everyone. This indicates that you will need to be familiar with and comprehend the meaning of a wide array of signals and flags used to direct the flow of boat traffic.

After all, ensuring your safety behind the wheel and warding off potential dangers below the water are essential components of boating safety.

In the following paragraphs, we will discuss the significance of the red flag and what steps you should take if you encounter one. In addition, we will provide some professional tips for responding appropriately if you find yourself in the water with a specific subset of watersports enthusiasts.

Do you want further information? Continue reading to arm yourself with the critical knowledge you'll require to keep yourself and others around you safe.

What Exactly Does That Red Flag Mean?


Denzel James Dockery, a veteran of the United States Navy, designed this flag back in 1956. In addition, Ted Nixon of US Divers was the one who popularized it in subsequent years. This essential gear, also known as the diver down flag, is something that every scuba group should bring along with them and display.

To comply with the legislation, divers in the United States of America, Canada, and certain nations in Europe are required to display it while they are underwater. However, there is a significant likelihood that the diving group is not immediately beneath their flag.

Scuba divers should maintain a distance of no more than 300 feet (90 meters) from their dive flag or stationary buoy in open water. The recommended distance is one hundred feet or thirty meters shorter in waterways such as rivers, inlets, and channels. In addition, scuba diving groups should make plans to surface within 45 meters (150 feet) of their dive flag whenever possible.


The diver down flag needs to be at least 20 inches by 24 inches and should be flown from the highest position on the vessel. This will ensure that it is seen from a considerable distance. If the flag is to be displayed from a surface marker buoy, it needs to be mounted in an upright posture, and it needs to be at least 12 inches by 12 inches in size.

Additionally, the blue and white alpha flag is permitted to be flown by divers in some areas of the world. When a vessel's mobility is limited in some way, this internationally recognized symbol is displayed to let other people know about it. It is common to practice to fly this flag alongside the diver down flag whenever there are divers present in the water. It signifies that other vessels should give way to the boat that is currently in the water.

Safety Concerns When Boating Near Scuba Divers

It would help if you never put yourself in the position of divers while you're driving or captaining a boat since it's irresponsible. When in doubt, maintain a distance of at least 300 feet between your vessel and its flag.

Bear in mind that despite the fact that displaying the diver down flag is mandated by law, not all dive groups choose to do so. You should constantly be on the watch for persons in the water, even if you do not see a flag or buoy indicating that there are people in the water. After all, the alertness of the operator is the most effective technique to forestall the occurrence of mishaps.

Safety Advice Related To Scuba Diving

Keep in mind that surface divers won't always be easy to spot since this is another crucial fact to keep in mind.

It may be difficult to see the waterline if you are in small, open watercraft such as a Jon boat due to the glare from the sun and rough weather conditions such as heavy waves and swell. It's not uncommon to have larger pontoon boats packed to capacity with visitors milling about. This could potentially obstruct your view while you are driving the ship, which is one of the many reasons why passengers should remain seated whenever the boat is moving.

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If you are aware that there are divers underwater nearby, it is imperative that you establish direct communication with the vessel that they are aboard. Even when it is not turning, you should make sure that these scuba divers do not come into contact with the propeller of your submarine. Even a stationary propeller poses a threat of severe injury if it comes into unintended touch with a person.

Make sure that there are no divers in the area or underneath your propeller before you start your boat. This can be performed by having a conversation with their captain or driver and keeping an eye out for bubbles coming from the ground below.


Despite your best efforts to avoid them, accidents can still occur. Make sure that your boat has everything on board that is required to handle any emergency that may arise while it is out on the water. This should include a staff that has considerable training in emergency first aid as well as a first-aid package, an oxygen unit, communication devices, and a communication device.

In addition to this, you should have a strategy ready to implement in case of an emergency. This comprehensive list of protocols should contain instructions on what to do in the event of an injury or accident, as well as specifics of how to evacuate the area in an emergency.

How To Proceed

On the water, your safety should always come before everything else, no matter how much fun you're having! If you see a red flag with a white diagonal stripe on it, your best bet is to keep moving in the opposite direction.

Divers could be required to carry out their safety stop at depths as shallow as 15 feet (five meters), depending on the circumstances. Even though the submerged group can hear and see your engine, they will have difficulty determining which direction you are approaching because of how loud it is. Staying away from the location totally is the most prudent line of action to take in order to keep everybody safe.

Don't freak out if you inadvertently come closer to divers who are working at deep than you wanted to.


To begin, you need to bring your boat to a complete halt and turn off the motor as quickly as possible. Although this may be bad for your engine, it is vital in order to ensure the safety of the divers who are below you. In the blink of an eye, a moving propeller can cause significant harm to a person.

As soon as your boat has come to a complete stop, elevate your prop if you can. Divers who surface in the vicinity won't put themselves in danger of inadvertently cutting themselves or bumping their heads on this substantial piece of metal if they do this.

Make touch with the dive boat and make an effort to determine where the group is submerged so that you can depart the area in a controlled manner and without risk.

Safety Advice Related To Scuba Diving

There are a few other essential considerations to consider regarding the safety of scuba divers and boaters.

Dive groups will sometimes display a surface marker buoy instead of flying the alpha flag or the red flag in certain circumstances. This particular kind of marker, which can also be referred to as an SMB or a DSMB, is utilized by dive groups in specific scenarios when they are underwater.

In certain instances, dive groups may intend to ascend to the surface in a location that is distinct from the one where they entered the water. This type of dive is referred to as a drift dive. In this particular scenario, the SMB or DSMB is utilized so that their boat can more easily indicate their location and track them as they go through the sea.

The prudent usage of this buoy during a dive group's safety stop or in the event that the group becomes separated underwater is another possibility. The vast majority of the time, deploying this flag is to make contact with their vessel rather than to serve as a warning to those in the area.

Even if your boat isn't moving, you should never forget to consider the safety of the divers swimming below it. This involves lowering swim platforms, ladders, and anchors, in particular. These objects are typically quite heavy and have the potential to injure divers if they come into contact with them while they are working at depth.


Other hazards include fishing lines, lures, nets, and traps. There is a significant possibility of unintentional entanglement due to the ease with which fishing gear can become entangled with dive gear. This can be one of the most severe emergencies a diver faces while underwater, and in some cases, it can even result in the diver drowning.

If there are divers in the vicinity, it is vital for the people riding on your boat to use extreme caution whenever they are entering or exiting the sea. Accidentally jumping onto the aluminum or steel tank of a diver might easily cause a swimmer to get a severe injury. In addition, depending on whether they are engaging in recreational or technical activities, the group of divers may be transporting heavy equipment that, if made touch with by non-participants, could cause injury to those individuals.

In conclusion, it is essential to be aware that divers communicate with one another on the surface via hand signals. A diver is indicating that everything is okay by making a massive circle with both arms raised above their heads. However, a diver who makes the motion of wiping their windscreen with both arms indicates that they are in a state of distress and may be suggesting that they are in a potential emergency scenario.


If you come across a diver who is having trouble, you should only go into the water if there is no other option. To begin, you need to make an effort to perform an in-water rescue by making use of floating gear such as a life jacket or a safety ring. You might also attempt tossing the diver a rope or extending a paddle towards them to make contact with them.

It is imperative that you keep these items on board in order to safeguard yourself and the other passengers. You never know when someone from your vessel can accidently fall in or become terrified on the surface, needing a similar rescue procedure. If this happens, you will need to be prepared.

Enjoyable And Risk-Free Activities For All


You are prepared to have a safe and enjoyable day on the water now that you have some knowledge about the red flag that is displayed by scuba divers and what to do in the event that you come across it.

Whether you're spending your time above or below the water, it's important to keep in mind that boating safety is an essential component of watersports. In addition, whenever there is any uncertainty, you should always err on the side of caution.

It is vital to remember that boating safety is a fundamental component of watersports and that this should be the case regardless of whether you spend your time above or below the water. In addition, you should always err on the side of caution, even if there is just the slightest amount of uncertainty.