REDUCING PROPELLER-RELATED INJURIES
Propeller strikes are one of the most serious but preventable mishaps out at sea. Learn more about the safety protocols that can help you stay safe while surfacing
As scuba divers, it is inevitable that we share the water with boats and often rely on boats to get us to and from dive sites. Therefore, it is vital that boat operators and divers are equipped with skills and information to help prevent propeller strikes.
At DAN AP, we are running a targeted safety campaign focused on propeller injuries and boat awareness as we continue to see severe injuries and loss of life resulting from avoidable propeller strikes. In fact, there have been 31 known scuba/snorkelling fatalities attributed to boat/propeller strikes in the Asia-Pacific region between 2009 and 2018. This figure is likely to be much higher, as many incidents go unreported.
Although laws vary by country (and state), divers should generally stay within 100 metres of a diver-below flag in open water. When surfacing, you should stay as close to the flag as possible. Unfortunately, many boat operators are not familiar with the flag’s meaning, or the related laws and will still come within exclusion zones. The safest place for any diver on or near the surface is as close to the dive flag as possible.
Our statistics highlight that there is a larger incidence of propeller-related accidents occurring within developing countries in the Asia-Pacific.
Why is this?
• The training and regulating of boat drivers is not as stringent in developing countries as it may be in other parts of the world
• There is a general lack of awareness of dive flags
In addition, in the event of an incident, medical facilities in remote parts of these countries are basic and not as well-equipped to deal with severe trauma.
If you are diving or snorkelling in developing countries of the Asia-Pacific, or anywhere else in the world, use signalling tools, listen carefully and be aware of boat movement while at or coming to the surface.
IN-WATER SAFETY TIPS FOR DIVERS Use Signalling Tools
Dive flags. Flying a dive flag can be an effective, and in some places required, means of alerting boats that divers are in the water. The two types of flags most commonly recognised in relation to diving are the alpha flag and the diver down flag.
The internationally recognised alpha flag is flown when the mobility of any vessel is restricted, indicating that other vessels should yield the right of way.
This flag can be flown along with the diver down flag when divers are in the water, because dive boats must maintain a close vicinity to the divers and cannot quickly move. The alpha flag indicates that divers are in the area. However, it also has other uses.
A diver down flag is recommended to alert vessels during shore diving. A floating buoy tethered to a dive reel can be used to signal where divers are located in the water. A reel towing a floating dive flag should never be attached directly to the diver. Carrying the reel helps prevent the diver from being dragged in case the flag is caught by a passing boat.
Whether the dive flag is flown on a boat or a buoy marker, the flag should be in good condition to ensure visibility. Replace the flag when the safety integrity is compromised by faded colour or rips. The diver down flag should be at least 50 centimetres by 60 centimetres (or as dictated by local laws) and flown above the vessel’s highest point. When displayed from a buoy, the flag should be at least 30 centimetres by 30 centimetres. Always make sure the flag is visible from all directions.
Surface markers. Safety tools such as surface marker buoys (SMBs), whistles and other audible signals, dive lights and signalling mirrors can be used to communicate your location to boaters after you ascend from a dive. An SMB may be used in addition to a dive flag for alerting boaters that divers are in the water. Before the dive, review how to deploy the SMB to be prepared for using it on ascent.
When using signalling devices, divers should never assume they are visible to boat operators
When using signalling devices at the surface, divers should never assume they are visible to boat operators. Glare from the sun, waves, passengers, weather conditions and other factors can make noticing a diver in the water difficult.
Be Attentive Underwater
In addition to using signalling devices and paying attention to boat traffic topside, divers must be aware of passing boats when they are underwater. Looking and listening for boats overhead is a good practice but keep in mind that poor visibility and sound localisation when underwater can interfere. In most cases, a diver should be able to hear a boat from underwater, but it may be difficult to localise the direction from which the sound is coming because sound travels approximately four times faster in water than in air. Wearing a hood may alter hearing thresholds even more.
A safety stop at five metres allows a diver to decrease nitrogen uptake and is also an opportunity to scan for boat traffic before ascending to the surface. Divers should be careful not to rely on quick reaction time in the event that they must move away from a passing boat while underwater. A boat can rapidly close in on an unknowing diver without always granting enough time to move a safe distance away. For these reasons, it is not advisable for divers to rely on observing for boats under the surface without a surface signalling device.
Have an Action Plan
A plan for treatment and evacuation of a diver struck by a boat or propeller should be in place before arrival at the dive site. To treat a laceration wound, stem the loss of blood by applying direct pressure to the wound immediately, and then applying pressure bandages. If there is an amputation of the arm or leg, a tourniquet (applied by someone with appropriate training) may be the best, or only, way to stem the bleeding. A victim of severe bleeding needs urgent medical attention. Movement should be minimised and oxygen first aid provided as it can reduce the accompanying shock. Know who to call and what role others play in responding to a medical emergency.
Research and Prevention
DAN Asia-Pacific is currently running a Propeller Injuries & Boat Awareness Safety Campaign to create awareness amongst boat operators and divers on how to safely share dive sites.
To report a diving-related incident, we encourage you to share the information via a form available on the Accident Reporting & Research section of the DAN AP website. The information on reported cases is used for case summaries and to create prevention materials.
TOP The diver down flag should be flown above the vessel’s highest point
ABOVE Surface marker buoys (SMBs) can be used to communicate your location to boaters after you ascend
ABOVE Propellor incidents are preventable as long as both divers and boat operators are alert and aware