Team Cave Diving in UK Sumps

Team cave diving presents unique challenges in UK sumps. The cold water, restricted passages and low visibility found in British caves create an environment that differs greatly from the large, clear cave systems where traditional team-diving methods developed.

This review examines how divers who normally operate independently can adapt selected team-diving principles to UK side-mount cave diving.

The information does not replace the formal team-diving training that other organisations use in different cave environments. True team cave diving relies on specific procedures, communication methods and shared skills that divers must learn within the relevant team or training system.

Because of the nature of many UK sumps, the Cave Diving Group (CDG) often uses the term group diving rather than team cave diving.

Group diving refers to two or more divers entering the water together. It can improve safety, efficiency and problem-solving during suitable dives. However, it does not replace the individual competence required for British cave diving.

In some UK sumps, especially tight or zero-visibility passages, a solo approach remains the safer option.

Team diving or Group Diving?

A recent review and update of the CDG risk assessment along with a review of Project 2020 prompted an analysis of the frequency of solo dives versus multiple divers in the same sump. The analysis, based in dives recorded in the CDG NL, showed that divers work together frequently for a variety of reasons with the average being 2.05 divers present for each dive. The CDG manual acknowledges (page 37) team diving and gives some basic guidance without any detail.

Multiple solo divers in the same sump create additional risks unless divers coordinate their actions. By learning from team diving methodology the group diving techniques listed in this document can reduce risks and avoid confusion.

Group diving can offer greater safety in some situations, and CDG divers already use it, most notably during training and experience building dives. CDG divers typically use a side mounted, independent cylinder configuration that does not support gas donation for the majority of dives in the UK. That said, team diving is not a replacement for individual competence, nor is it a method of dependence. It compliments the competence of each individual diver and when used in the right place, enhances redundancy, efficiency and safety.

What constitutes team cave diving:

• Divers must maintain visual or physical contact with each other.
• Divers communicate with each other routinely using passive light signals, hand
• signals or light signals.
• Divers offer assistance to each other in the event of problems and emergencies.
• Divers work together to achieve a goal.
• Identical procedures, protocols, skill set, experience and knowledge.

Must haves for team cave diving to work:

• Underwater communication skills.
• Pre dive team briefing.
• Division of tasks between divers as required for the specific objective of the dive. • Diving skills to protect visibility.
• Diving skills to donate a breathing set including air sharing.
• Familiarity with team members personal dive equipment configuration.

The advantages of team cave diving are:

• More eyes – divers can spot problems for each other.
• More brains – more possible answers to problems.
• More hands – divers can help each other by problem solving and fixing issues.
• More labour – a large job can be broken down into small individual tasks and distributed between team members.
• More gas – gas reserves may be pooled, managed, handed off or fetched by a team member.

A group of CDG solo divers does not meet the team cave diving requirements described above but there is no reason why some of the advantages of team cave diving cannot be achieved for some dives. By adapting team diving techniques and adding them to the solo skill set divers working in a group will be better placed to help each other out should the need arise or combine their effort to achieve a complex task. The divers will still not be considered a team but they can be considered a group if they have and use the necessary skills. Each diver in the group will be a solo diver who can help other group members.

Dives that are most likely to benefit from a group diving approach:

• Open water training dives.
• Experience building dives in sumps.
• Surveying dives when working to a high survey grade.
• Underwater digging.
• Transportation of large items of equipment through a sump. • Underwater filming (photography and videography).
• Staging cylinders for longer/deeper dives.
• Social diving.
• Multiple divers passing the same sump to cave beyond.
• Dives requiring large quantities of bailout gas.

Sumps that make it difficult to gain from the advantages of team cave diving are:

• Tight sumps which limit access to other team members.
• Short sumps where it is quicker to return to base to resolve a problem.
• Sumps with very low or zero visibility where communication becomes very difficult.
• Sumps with high flow where maintaining relative distance from team members may prove difficult.

Group diving principals

Configuration changes:

UK cave diving requires a side mounted, independent cylinder configuration for the majority of sites. This configuration does not suit team cave diving well, so divers may need to modify their equipment depending on the dive objective and group skills.

• Long hose: One of the biggest advantages of team diving is the ability to donate gas. Divers carry a long hose on the right-hand sidemount cylinder so they can donate gas easily to another diver.
• Hand held light: Helmet mounted lights make using light signals impractical and will dazzle other divers when attempting hand signals. A hand mounted light makes passive light signals and deliberate signalling easy.
• Brain: Group diving will need changes to the mindset of the solo diver not only in learning new skills but also in how to apply them to get the best advantage.

Underwater communication skills needed for team cave diving:

• To get access to some of the advantages of team cave diving, divers need to communicate. There are several methods, hand signals, light signals, touch and rebreather divers may attempt slow and clear enunciation of words into their breathing loop.
• A diver may struggle to read hand signals when another diver’s lights dazzle them. Group members should direct their lights downwards towards the hand signals (or switch them off) and away from other group members eyes.
• Divers can create clearer light signals with a hand-mounted or handheld light instead of relying only on helmet-mounted lights. In practice a mixture of the two signal types will be most useful, hand signals when group members are facing each other and light signals when the group is swimming along in line astern. Light signals are best created by directing a tightly focused beam on the floor of the sump underneath or slightly ahead of the diver in front. Passive light signals make it easier for the divers in front to communicate with those behind without having to turn and look. The movements available to signal clearly with a light are limited, a torch beam can be rotated clockwise and anticlockwise or moved in a straight line left to right or up and down.
• Once divers can communicate effectively with each other they can work as a group to achieve an end goal but communication is clearly limited to a few agreed signals. More complex messages will need wetnotes. This is time consuming and can largely be avoided with a detailed pre-dive briefing so that each group member knows what their allocated role is on the dive.

Hand signals:

• End dive – one handed thumbs up as used in open water training.
• Okay – as used in open water training.
• Problem – flat hand, rocking side to side.
• Out of air – hand across the throat in a cutting movement.
• Bubbles – repeatedly touch thumb and index fingers together to indicate gas leak in equipment.
• Read your gauges – two fingers in the upward facing palm of the other hand.
• Stop Moving – one hand, fingers rolled over into palm that is facing the diver being signalled to stop.
• You watch me (training dives) – one hand, point to the diver who needs to watch then point two fingers towards your mask and then point to yourself.
• Repeat task or drill (training dives) – two hands, rotate hands around each other horizontally.
• Shut your eyes (training dives) – one hand over mask, there must be an agreed eyes open signal usually a tap on the shoulder.
• One handed numbers – 1 through five, front of hand; 6 through 9, back of hand.
• What is your deco – clenched fist with raised little finger.

Light signals:

• Slow steady clockwise rotation – okay.
• Slow steady left right horizontal sweep – attention.
• Rapid up and down horizontal sweep – help/emergency. (Whatever gets the attention of other divers in the group.)

Touch signals:

• Tap on the shoulder – end drill and open your eyes.
• Tap on the head – end dive.
• Hold a hand – to guide a diver into touch contact with the line.
• Hold a hand stationary on the line – stop moving.
• Leg squeezes – push: go forward, pull: back up, squeeze: stop, loss of contact: stop, repeated squeezes: emergency.

Pre-dive group briefing

The pre dive briefing is where the individual divers form into a group with a shared objective. Without it there is no group. The briefing needs to be led by one person who will run through the proposed dive and check that all group members understand the plan and how they will work together to achieve the goal of the dive. On a social dive this may be as simple as a basic dive in to a point and returning in an established group order. On an underwater digging trip, the briefing may have to cover complex activities such as building scaffold supports or moving spoil away from the dig face.

This will include:

• The objective of the dive.
• Turn point or pressures.
• Exit plan (this may include more than one option depending on circumstances especially when doing multi sump trips).
• Line details including all junctions, air-bells, exit bearing, significant features and line condition.
• Passage details including restrictions, passage conditions with regard to movement and visibility, depth, current, unstable sections and any known differences.
• A detailed run through of underwater tasks including who will is responsible for each step.
• Verify hand/light signals to be used on the dive paying particular attention to task specific signals.
• Division of tasks between divers as required for the specific objective of the dive.

The need for division of tasks is highly dive dependent. For some dives it will be less task intensive, such as social dives or divers simply passing through a sump. For dives that will move equipment through a sump or carry out digging in the sump, task division will be a critical factor in the amount that is achieved on the dive.

• Tasks are to be matched with each diver’s ability – Do not taskload anyone.
• A task must have a clear beginning and end point, as overlapping tasks can create confusion.
• Part of a task that requires interaction with other divers must be clearly defined.

Diving skills to protect visibility.

Protecting visibility is good when solo diving and critical when group diving. Loss of visibility effects the simplicity of light and hand communication.

• Team divers need to take great care to use techniques that will not disturb silt and other deposits.
• Divers must maintain good buoyancy and trim.
• Divers must use appropriate propulsion techniques such as the flutter kick, frogkick or pull, pull and glide.

Gas sharing using a long hose.

The reason for team cave diving is assistance by the team members if required, in the event of a serious gas failure or contamination of the gas supply, a long hose that can be donated easily to another diver is carried on the right hand sidemount cylinder. The long hose is generally two meters in length and can be either stowed along the length of the cylinder or half stowed with the remainder hog looped around the divers neck. In the event of gas sharing being necessary the out of gas diver can swim next to the donating diver or if passage size is small the out of gas diver swims in front of the donating diver. The long hose gives the ability to pass restrictions whilst sharing gas. It’s highly recommended that divers maintain physical contact during gas sharing and the drill is practiced regularly.

Gas sharing by donating a breathing set.

The use of independent breathing sets by the CDG along with faulty breathing set drills makes a complete loss of gas very unlikely. The one situation which can easily create such a double breathing set failure is contaminated gas from a bad fill. In the UK, when only using two cylinders, gas contamination is likely to be noticed at the start of the dive or when the dive first gains depth. In this situation a team member can donate a breathing set if the size of the passage allows, the donating diver will be well within thirds.

• Signal an emergency out of gas.
• Team member donates a second stage.
• Once the compromised diver is comfortable swap cylinders (steel cylinderssignificantly effect buoyancy so the donating diver may have to pick up the breathing set that the compromised diver removed to maintain buoyancy).
• Exit.

Summary

Diving as a group requires some additional skills on top of the usual solo skills while at the same time maintaining these solo diving skills. Below is a list of the new skills needed for group diving along with some solo skills which divers can become complacent with when group diving.

• All divers must be connected to dive base by a continuous line at all times.
• The group must travel at the pace of the slowest member.
• When one diver ends the dive all divers head out together.
• All group members must use individual line markers at junctions.
• Divers must not remove other diver’s junction markers.
• All divers in the group must have the necessary communication skills.
• All divers in the group must be able to dive without reducing the visibility.
• Immediately prior to the dive all group members must take part in a detailed briefing to prepare the group to work together.
• Communicate with each other during the dive, keep track of other group members.
• Group members in need of help must remain still to allow other divers to easilyview, assess and resolve a problem.
• If a group loses track of one of its members, stop perform a visual search, if that fails return along the line to dive base.
• If a diver loses track of the rest of the group, stop perform a visual search, if that fails return along the line to dive base.
• When passing a narrow section of passage the lead group member waits for the last diver to pass through it before proceeding.
• Do not use small air-bells as a group, any oxygen in airspace will deplete quickly.
• In the event of loss of visibility maintain contact with the line and continue the dive while attempting to re- establish contact with the other members of the group.
• After passing a constriction all divers in the group must wait until the last diver is through and signals okay.