A Diver Loses the Anchor Line
A pleasant balmy morning and the divers are out for a plunge into the sea at a favorite dive site. The anchor is picked on a feature that comes up to 20 m, but the sand is at 40 m so there's always the expectation that you could end up needing to go to that depth. Some current, though not too bad, but the wind and the current are opposed so the anchor line forms a big arc under the boat and over 50 meters of line is let out. The divers go in, two together going first to check the anchor and set it well, then some minutes later the second group with 3 divers start to go down the anchor line. Now, fast forward to only a handful of minutes later. The third member of the second group has vanished on the way to the bottom. Imagine how all of the divers concerned now feel - the two divers who have lost a buddy, and that buddy who has separated from the others, many kilometers offshore.
The buddies who discovered that diver X was missing reacted as most of us might do - some quick signals and one waits at the bottom of the anchor line, while the other ascends the anchor expecting to find the missing partner somewhere along the rope. However, they don't find them - and they continue up to the boat in case diver X has had a problem, aborted the dive and gone back to the boat. A quick check of the boat reveals that the missing diver isn't there. Adrenalin is really pumping now. Quickly back down the anchor to pull all the divers back so a search can commence. A message is written on a slate so that this can be shown to the first group and used to recall the first divers - who by now have a fair amount of nitrogen on board and need to vent off at 5 meters for a while. Message relayed, and the anchor is quickly placed ready to pull and all now ascend to make their safety or degassing stops. The diver from the second group who didn't yo-yo up and down the line cuts the safety stop and goes up to the boat. Shortly after, all are relieved when a big OK signal is signed in the water back to those on the line. The missing diver is now back in the boat.
The diver who went missing had followed the others down the line and passing ~ 30 meters as the line extended horizontally to the top of a ridge on the underwater reef could see the bottom below them, released the anchor line and descended. However, there was a bit of a current and the visibility wasn't great and he suddenly finds he can't see the anchor line. He makes the decision to continue to the bottom in the hope that he will find the others, or at least see their air bubbles ahead so they can find them. However, this proves not to be the case, and so he commences a free water ascent. Pushing maximum ascent rates and skipping the safety stop (this certainly warranted doing so) he comes to the surface and looks for the boat. Good procedure - he makes a full 360 degree turn to find it, but nothing is to be seen. Another full 360 - and again nothing, and a growing sinking feeling in his stomach. Once more, and this time he and the boat are at the top of a wave at the same time and the top of the dive flag is spotted, still some way away and up-current, but reason enough for a big sigh of relief. A solid 5 minute swim to reach the 30 meter mermaid line, but then OK, and back into the boat.
After the divers are back in the boat, and then back on the shore, much discussion ensues. All ended up safely, though with rapidly beating hearts. Some luck, but also some very sound actions. What positive things can we take from this incident, and what are things worth considering if this happens to any of us on another dive?
- Unless there is a clearly stated reason to do so, always hold onto the anchor line all the way down and make sure you come up on it also. Currents, poor visibility, and depth all combine to make this a must.
- If you are descending with a group, descend at the rate of the slowest in that group. This often will mean you'll need to turn around and check on others. Usually, a delay could just be problems equalizing ears, but it could be gear getting tangled and a real need for a buddy to help out. In any case, if the anchor has already been set, do you want to be consuming air at depth for 5 minutes while you wait for a buddy to come down and meet you? You can use a lot of air while waiting at depth!
- Is there an agreed "lost buddy procedure"? The one generally taught to open water students is if you lose your buddy, look around the immediate area for no more than a minute and then make a controlled ascent to the surface. More advanced circumstances can benefit from something different, and to make this work you all should discuss these options. In this case there could have been good arguments for both of the remaining divers in the second group not to separate and to ascend the line together, but given that a "lost buddy procedure" had not been explicitly discussed and that they were still connected by the anchor line, leaving one diver on the bottom of the anchor in case the missing diver came into sight was not unreasonable. Equally, in current and a poor visibility situation, after losing sight of the anchor line and the other divers it would probably have been better for the "lost" diver to have gone directly to the surface and not the bottom - chances are this could have seen all of the three divers in the second group reunited at the surface and still able to recommence their dive.
- Going all the way back to the boat and checking in there was a very good action. It permitted a rapid recall of all divers so that if someone was lost at sea, the boat could start looking before that person had drifted too many kilometers downstream.
- If you have to, you'll need to make a blue-water (free) ascent. When doing this always try and swim into the current and use your gauges/compass to control ascent rate and direction. Remember that a safety stop is not an obligation, and sometimes safety requires that you go straight to the surface and find the boat.
- When you get to the boat after a separating from a group and making a free ascent, it would be helpful to signal to any others coming back up the line that you are OK.
- While the SS doesn't like noisy underwater hooters/buzzers connected to your low pressure feed when they are used to communicate generally, they can be a very good device when used strictly in emergencies to recall a dive. Also, making a repeated regular noise with a weight on a tank or the hull of the boat - we'd suggest three thumps repeated regularly - can be a good thing to remember. We are also aware of situations where a repeated pattern of revving the boat motor has been used as a dive recall signal, though this one can get confused by other boats around. Of course unless we all are aware of these sound signals in our environment, and the fact that they can have meanings, they have little use - so always be alert and consider the possibility!
- Diving in a group of three definitely requires extra planning and vigilance. Any extra person in a buddy group multiplies the number of buddies you need to watch for, the potential options with communications and lost buddy situations, and any potential problems and possible misunderstandings. It can be done safely, but there are more things to consider.
- Finally, no one is too experienced to discuss safety/ emergency procedures before a dive. Reading minds isn't something that experienced divers are especially good at, so even they should discuss in advance what the best options in the majority of situations would be.