Although we'd often like dives to last longer, as the mantra goes, we must 'plan the dive and dive the plan,' making our way back topside at the appropriate gas level or no-decompression turn points. And when it's time to head to the surface, it's important to follow safe ascent procedures.
Most training agencies feature some common steps for ascent procedures in their initial dive training courses. What are they? And, more importantly, how might you apply them in different scenarios?
The PADI and SSI systems feature lots of overlap and few differences in the Venn diagram of ascents. Within the PADI system, for example, the pneumonic STELA is often used. But what does it mean?
Step 1: Signal to your buddy
Make a final confirmation to your buddy that the dive is ending and you're both ready to ascend. Signal 'up' and wait for their confirming signal in agreement before proceeding. You should ascend together at the same rate.
A signal is also a way to confirm that you're in the right area for an ascent. You may intend to ascend using the boat's anchor line as a reference. On a wreck dive, you may be ascending up a shot line to a surface buoy. In a free- ascent, you might need to swim away from the reef into the blue to facilitate a safe boat pick up. And when shore diving, you'll want to signal for that final turn toward the beach or shoreline.
Be clear with your buddy. Signal clearly where you'll ascend, whether indicating an anchor line or a swim away from the reef. Take a compass bearing if required and wait for agreement. Be sure you're both on the same page — it's not uncommon for buddies to become separated during the final stages of the dive due to distraction or a lack of communication on the final ascent.
Step 2: Time and gas
If all has gone to plan, this should be a formality. First, double check with your buddy that you're both within agreed-upon time limits for the dive. On most recreational dives, this means confirming you're safely within your dive computer's no-deco limits. If you've inadvertently gone into decompression, you'll need to perform the required stops in accordance with your dive computer's instructions. If you've stayed too long in error, follow your contingency plan with your buddy – whether that's table or dive-computer instructions.
Check your gas. As with no-decompression limits, if you've planned and executed your dive correctly, you will plenty of gas for your final ascent, safety stop and surfacing. If there is a problem, implement your contingency plan. Either way, signal your buddy so you both know your situation.
Sometimes, at this stage, divers may deploy their DSMB when necessary. Others may deploy during the safety stop. Listen to the briefing for environmentally appropriate procedures. If a buddy team is going to deploy a DSMB, agree on who will be doing that with your buddy before the dive begins.
Step 3: Elevating
You and your buddy have agreed to go up and you know where you're ascending. You're within planned time limits and have the appropriate gas reserve. Moving shallower in the water column will mean the gas inside your BCD or drysuit will begin to expand. Elevate the appropriate area to the highest point and vent the expanding gas, which may mean holding the LPI hose of your BCD or wing in your left hand. If you're using a drysuit, ensure that the exhaust valve is open sufficiently for the ascent. Get in the habit of stowing or clipping on any accessories you don't need to leave hands free.
Similarly, when using a shot line or anchor line as a tactile reference, take the line in the right hand. Leave your left arm free to vent your extended LPI hose, reach over to your right shoulder dump valve toggle, or raise your drysuit exhaust valve.
Step 4: Look
Look where you're going. Water movement, changes in visibility, light, movement of boats, and other divers can all be potential hazards above you.
Some agencies recommended that you raise your right arm to protect your head as you surface. Others suggest grasping your weight system with your right arm prior to tilting and ascending, in case it's loosened as your exposure suit compressed under pressure. Much will depend on how and where you're making your ascent.
If you're leaving a reef for a boat pick-up, swim into the blue. This allows the boat more space to pick up divers without drifting close to the reef and potentially causing damage. Be aware of boat traffic above you. Sound, which travels four times quicker through water, can give the impression that boats are directly above you. Be sure to look around.
If you're ascending up an anchor line or shot line, watch for those ascending above you, as well as any who might be descending along the same line to begin their dive. It's common dive etiquette for ascending divers to have right of way and descending divers to make their way around, leaving the line if required. However, leave as much space as you can — it may be difficult (or impossible) for other divers to leave the line if there is a current. And expect the unexpected — not every diver is as polite as they should be and it's not uncommon to receive the odd nudge or kick from divers who lack spatial awareness.
Step 5: Ascend
Monitor your speed as you go up. Guidelines vary from 60 feet (18 m) per minute to a more conservative 30 feet (9 m) per minute, with many recreational dive computers favoring the latter. Understand your computer's display and how to decipher the information. Mount your computer somewhere you can read it during your ascent to monitor the rate. If you feel you'll struggle, link closely with your buddy and ascend no quicker than they do. If you're diving with a guide, stay slightly behind them on the ascent and ascend no quicker than they do. If you're diving independently with a buddy, stay close and ascend at the slowest member's pace.
Adjust your buoyancy at regular intervals during ascent. Let the equipment do the bulk of the work though — you shouldn't have to kick hard to ascend. Level off at 15 feet (5 m) for your safety stop. Stay neutrally buoyant and be aware of other divers. Confirm your gas supply again and confirm to your buddies all is 'ok.' If you've made a free ascent in open water, there may be water movement, so be mindful of your surroundings.
During the safety stop communicate how many minutes you have left: three, two, one. Finally, when all divers have confirmed that they've completed their stops, together you'll make the final ascent to the surface.
The last 15 feet (5 m) of the ascent is arguably the most important as there is the biggest proportionate pressure change. Stay close to your buddy. Ascend at the same rate. Monitor your ascent rate. If your team has one DSMB displayed at the surface, stay close to the person with the buoy. That's what boat traffic is looking for, not necessarily your bubbles. Surfacing several feet or meters away will leave you vulnerable.
Finally, as you breach the surface, establish positive buoyancy and signal to the dive leader that you're ok. Where possible, retain your mask and air source, ready for your exit.
There are numerous variations and individual preferences on safe ascent procedures. However, listening to the briefing, agreeing on protocol with your buddy, having a plan in place, and being aware of your surroundings will help you ascend safely with no unnecessary drama.
The post Training Fundamentals: Safe Ascent Procedures appeared first on Scuba Diver Life.
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