In-water signalling devices and floats are crucial tools that enhance diver safety by improving visibility and communication. In this guide, we explore the different types of signalling devices, their uses, and how they contribute to a safer diving experience.
Types of in-water signalling devices
1. Surface Marker Buoys (SMBs)
- Definition: An SMB is a brightly colored float used by divers to signal their presence to surface vessels and support boats.
- Usage: SMBs are typically deployed at the start or end of a dive to mark a diver's position. This helps surface vessels and dive boats maintain awareness of where divers are located.
- Benefits: The bright colors (usually orange or yellow) and visibility of SMBs reduce the likelihood of accidents by alerting boaters to divers below the surface.
2. Delayed Surface Marker Buoys (DSMBs)
- Definition: A DSMB is similar to an SMB but is deployed during the ascent to mark a diver’s position as they rise to the surface.
- Usage: DSMBs are deployed from depth to provide early warning to boaters that divers are ascending. This is especially useful in high-traffic areas and for divers engaged in safety stops..
- Benefits: DSMBs help ensure that boat traffic avoids the area, reducing the risk of accidents when divers are at their most vulnerable during ascent.
3. Dive Flags
- Alpha Flag: The blue and white Alpha flag signals to other vessels that a diver is down and that other boats must keep a safe distance.
- DAN Flag: The red and white DAN flag is another commonly used flag to indicate divers are in the water.
- Usage: Dive flags can be mounted on a buoy, float, or boat, and must be clearly visible to be effective.
4. Audible signalling devices
- Whistles and Air Horns: Devices like whistles or air horns attached to a diver's BCD can be used to attract attention at the surface.
- Usage: These are especially useful in situations where visibility is poor, and a diver needs to attract their dive boat or communicate with other divers at the surface.
- Benefits: Audible signalling devices provide an extra layer of safety by allowing divers to signal for help if visual markers aren’t sufficient.
5. Signal mirrors and flashlights
- Signal Mirrors: Mirrors are used to reflect sunlight and create a highly visible flash that can be seen from a distance. They are particularly effective when divers need to attract the attention of boats.
- Underwater Flashlights: Flashlights can be used for communication during low-light conditions, such as night dives or in murky water.
- Usage: Mirrors and flashlights are excellent for gaining visibility when other means are unavailable or ineffective.
How to use in-water signalling devices effectively
1. Deploying an SMB or DSMB
- Practice Deployment and retrieval: Deploying and retrieving an SMB or DSMB requires practice to avoid entanglement or uncontrolled ascents. Divers should practice using these devices in controlled environments before using them in open water. See the video below for examples.
2. Attaching Signalling Devices to Your Kit
- Whistles and Mirrors: Attach these devices securely to your BCD in an easily accessible location. In an emergency, you should be able to reach and use them without any trouble.
- Floats and Flags: Floats and dive flags should be deployed before entering the water and maintained in an easily visible position throughout the dive.
Common mistakes and how to avoid them
1. Not carrying a signalling device
Many divers skip carrying signalling devices if they think conditions are “safe enough.” However, weather and surface traffic can change rapidly. It’s crucial to carry at least one visual and one audible device on every dive.
2. Improper deployment of DSMBs
Deploying a DSMB incorrectly can lead to entanglement or an uncontrolled ascent. Practice deploying DSMBs in controlled conditions until you are comfortable and proficient.
3. Neglecting Maintenance
Signalling devices can become damaged if not cared for properly. Make sure to rinse them with fresh water after every dive and store them in a dry place to extend their lifespan.
Conclusion
In-water signalling devices and floats are essential tools for any diver. They enhance safety by improving visibility, enabling communication, and providing ways to signal for help during emergencies. Whether you're a recreational diver or a professional, having the right signalling equipment—and knowing how to use it properly—can make the difference between a safe dive and a dangerous situation. Always ensure your equipment is in good condition, practice your deployment skills, and be prepared for any situation that may arise.
