Underwater hand signals are an integral part of any diver’s certification and a great way to communicate basic messages. But communicating while technical diving might require more than basic hand or even torch signals. Technical diving has some tools in its communications toolbox that open-water divers may find useful.
Communicating while technical diving
Watch technical divers signal each other underwater and it might seem like they speak a different language. Far from it, however. Techies have developed a system of hand signals that allows them to communicate fairly complex messages with as few precise signals as possible. The reason lies in the nature of technical diving: dives are generally more complex than recreational dives, both in terms of the dive objective and equipment. Divers must adhere to plans as strictly as possible to avoid low-on-gas situations and other problems. When something unforeseen happens, divers must quickly adjust.
One-handed communication is essential. The other hand is often occupied with a torch or a reel, to name only two pieces of equipment. Single-handed signaling starts with numbers to signal gas volumes and more. And the system is not complicated — after a few practice dives, many recreational divers prefer signaling this way. There are also simple signals for depth changes, usually consisting of an upward hand movement — ‘let’s go up’ — followed by the target depth. All team members then repeat this signal to avoid misunderstandings. After all, a diver signaling ‘okay’ might be confirming any number of things. Repeating the signal ensures that both divers meant the same thing.
There are hand signals for line laying, decompression time — or leftover no-decompression time as appropriate — entanglement and adding or subtracting dive time at specific depths. Many of these would benefit recreational divers too, as it’s common to near no-deco limits, for example, on repetitive dives.
Backing up basic communications
Technical divers then add back-ups to their basic hand communications. In situations too complicated for simple hand signals, many technical divers carry wrist slates and waterproof notepads. Scribbling down a sentence or two can make an underwater conversation much easier. But even writing things down underwater is not always straightforward and it does take time. Therefore, many teams will use pre-planned phrases they can simply point to as needed.
This is also useful when an underwater dive team needs support from their surface team, including additional deco gas or a support diver. Having pre-written messages, which the surface team is already familiar with through briefings, can really speed things up in tricky situations.
But what happens when, quite literally, the lights go out? Most technical diving takes place in relatively dark waters. Most technical divers rely on lights for most, if not all, of their communications and to keep teams together. If light failure occurs or masks become unusable, technical divers revert to touch communications, basically transferring all of the one-handed signals mentioned above into short but precise messages converted either from the lead diver’s hand to the other diver’s arm or, in case the divers must travel single file, to their leg.
This method of communication is certainly complex and requires a lot of awareness and concentration. But tech divers also practice extensively during courses, as well as on dives. Touch communications can be useful in open-ocean diving, but they are essential for any serious overhead diving, including wreck and cave penetration. Anyone training for these courses will practice exercises and scenarios without a mask until feeling the way out becomes (almost) second nature.
Keep in mind that much of the success of these more complex communications depends on what happens before divers get in the water. unpracticed touch communications are just as dangerous as illegible hand writing, especially under the influence of narcosis and stress. In-depth briefings, regular skills practice and thorough de-briefs are the keys to successful communications on technical dives.
Takeaway for recreational divers
So how does communication while technical diving relate to recreational diving? On any dive, there is a chance of something unforeseen happening — current can change; divers can face equipment problems; buddy pairs can become separated. Clear communication, even for complex messages, will go a long way to help resolve any situation. Recreational divers can and should carry slates as well, not only for communication, but also to record what they may have seen. Clear, concise communication means a more enjoyable dive, whether technical or recreational.