A safety stop is an important 3-minute stop that you should do at 15 feet/5 meters when making your final ascent to the surface, particularly for dives below 60 feet/18 meters.
Why are safety stops crucial
Each time you dive, you accumulate nitrogen in your blood and tissues when breathing compressed air. The deeper you go and the longer you stay underwater, the more your body absorbs nitrogen. When you make your way up to shallow water, the excess nitrogen begins to dissolve from your body which decreases the pressure of air imposed by the surrounding water.
When you ascend too quickly, it results in a rapid reduction of pressure and nitrogen gets washed quickly. The excessive pressure differential causes the formation of nitrogen bubbles in your tissues and blood vessels. It’s dangerous when these bubbles get trapped in your body because it can lead to a condition called Decompression Sickness or “the bends”.
Recommended safety stops were introduced in diving to give your body time to discharge the absorbed nitrogen before going back to the surface. It was added in the 1984 edition of the PADI Open Water Manual but it was opened to a wider audience in 1988 with the release of the Recreational Dive Planner. Through the years, the safety stop has become a common practice employed by PADI and other big dive training agencies.
During your Open Water Diver certification, you learned about dive tables and the significance of no-decompression limit (NDL) and remaining pressure groups. When you refer to your dive table and the NDL for any given depth, you’ll see that when you reach a time of 5 minutes prior to NDL, the suggested safety stop becomes an obligatory safety stop. By following the recommended and mandatory stops, you can protect yourself and your dive buddy from health hazards like Decompression Sickness.
Safety stop tips to remember
- No need to rush – Do not make the wrong assumption that once you’re done with your safety stop, you can already ascend as quickly as you want to the surface. You are still advised to keep it slow at a recommended 30-feet per minute pace to the surface to avoid the risk of lung-expansion injuries.
- Slowly but surely – When you are returning to the surface, monitor your computer or depth gauge closely to ensure that your ascent does not go faster than the recommended rate. Don’t forget to vent air from your BC as you go up and send a surface marker, especially if you’re going up away from your boat. You can use either a delayed surface marker buoy (DSMB), also known as the safety sausage or a surface marker buoy (SMB) to highlight your position in the water. This also makes it easier for the boat driver or spotter to keep track of you in the water even if you drift a little farther from the vessel. If there is low visibility or during night dives, submersible strobes or marking lights are helpful tools to mark the location of the anchor or up-line.
- Maintain proper position – Upon reaching 15 feet, you are recommended to keep your head up and place your depth gauge at chest level in order to keep your torso at the proper depth.
- Look for reference points – Aside from your depth gauge, you can also check your surroundings for reference points at 15 feet/5 meters that you can use to complete a safety stop such as shallow reefs.
- Keep a steady hand – If you’re following a rope attached to the boat, it is advisable to hold the line loosely with a single hand while keeping your arm outstretched. By doing so, you can avoid getting pulled up or down by the line.
- Monitor your own time – You should be accountable for your own safety stop that’s why it’s important to be aware of your depth and time spent underwater. Never depend on another diver to time your safety stops for you.
Mandatory safety stop
Making a safety stop is highly recommended at the end of each dive but it becomes mandatory in the following conditions:
- When you are diving to 100 feet/30 meters or beyond
- When arriving at 3 pressure groups on the No Decompression Limit (NDL) or Recreational Dive Planner (RDP).
Emergency Safety Stop
In the following situations, you may have to complete a longer safety stop than the normal practice:
- When diving 1-5 minutes longer than the NDL, you are suggested to complete an 8-minute safety stop at 15 feet/5 meters.
- When diving longer than 5 minutes beyond the NDL, you are advised to complete a 15-minute safety stop at 15 feet/5 meters.
- In the event that your timing device or computer fails, the best thing to do is to immediately but slowly ascend to 15 feet/5 meters and perform an extended safety stop.
Diving is an exciting and rewarding sport but you should always prioritize your personal safety when indulging in this activity. At Nemo Diving Center, we always follow safety protocols like making a safety stop to protect you from health hazards and ensure that you have a fun and safe diving experience.