ASF Free Diving Code of Practice

1.

Definitions

4.

Equipment

1.1.1

Free diving

4.1.1

Lights

1.1.2

Supplied air diving

4.1.2

Second light source

4.2.1

Masks

2.

Methods & Cautions

4.2.2

Goggles

2.1.1

Lines

4.2.3

Snorkels

2.1.2

High water levels

4.3.1

Fins

2.2.1

Trapped air pockets

4.4.1

Wetsuits

2.2.2

Pressurised air pockets

4.4.2

Weight belts

2.2.3

Foul air pockets

4.5.1

Dry suits

2.3.1

Hyperventilation

2.3.1

Hyperventilation

5.

Signals

2.4.1

Zero visibility

5.1.1

Agreed signals

2.5.1

Equipment aids

5.1.2

Suggested signals

2.5.2

Attaching equipment

5.2.1

Additional signals

3.

Lines

6.

Competence & Experience

3.1.2

Lines to suit environment

6.1.1

Treat with respect

3.1.3

Line replacement

6.1.2

Rescue call-outs

3.2.1

One line per passage

6.2.1

Competence in water

3.2.2

Lines in divided passages

6.3.1

Prior training

3.2.3

Securing lines

6.3.2

Dive skills

3.2.4

Intermediate tie-offs

6.4.1

Consider party experience

3.2.5

Secure line-ends

6.4.2

Silting of sumps

3.3.1

Laying new line

3.3.2

Secure new line to diver

1. Definitions

1.1.1 The use of breath-held free diving techniques to pass through (sumps) or into (syphons) water-filled passages that do not have vertical access to an air surface overhead.

1.1.2 Cave diving using SCUBA or other supplied breathing apparatus is covered in a separate code, ASF Cave Diving Code of Practice'.

2. Methods And Cautions

2.1.1 Every free diver must use a line in accordance with Section 3 of this Code.

2.1.2 Caution must be exercised in the event of higher than normal water level, as a dive may become considerably longer than expected or the line may end before an air space is reached.

2.2.1 Air trapped in roof pockets should not be breathed or relied upon (see 2.2.2 and 2.2.3).

2.2.2 Air trapped in roof pockets can be at higher than surface pressures. If this air is breathed and held during ascent, the free diver risks baratrauma of the respiratory system.

2.2.3 Again, air trapped in roof pockets may be foul air.

2.3.1 Hyperventilation, to increase the free diver's breath holding capacity, is discouraged. The risk of drowning if the free diver were to black out from this practice is much greater in this environment.

2.4.1 The intending free diver must be prepared to encounter zero visibility when contemplating such a dive, even if the water at first appears clear.

2.5.1 The use of equipment to aid a free dive into an underwater passage should be considered if practical (see Section 4).

2.5.2 Hooks, opening clips or karabiners without screw-gates must not be used to attach equipment to the free diver as they increase the risk of entanglement.

3. Lines

3.1.1 Lines, whether permanently fixed or temporary, may be floating or non-floating. However, they must have a breaking strain exceeding 500 kg.

3.1.2 Some cave environments will require a more substantial line, which must be used accordingly and/or replaced more frequently.

3.1.3 Lines used by cave divers are usually lighter and should be replaced with one of an appropriate strength.

3.2.1 Only one fixed line should be used or left through any waterfilled passage (see also 3.2.2).

3.2.2 In the case of a divided passage where both sections are negotiable, then a second line, well separated from the first line leading from the closest air space, is preferred rather than to use an underwater junction in the lines.

3.2.3 Any line must be firmly secured at each end above normal water level and well clear of any overhead projections.

3.2.4 Any intermediate tie-off that is used to avoid the line pulling into narrow restrictions must be easy to negotiate so as to avoid loss of direction or entanglement in zero visibility conditions.

3.2.5 Under no circumstances is a free end of line to be left unsecured.

Free diving into unknown sumps and/or sumps with no fixed lines must be done with a continuous line from the free diver leading back to the start of the dive.

3.3.2 A line can be laid by a free diver using a reel or it can be paid out by a surface party. Using either method, the line or reel must be made secure to the diver.

4. Equipment

4.1.1 Lights must be of a type to be reliable in operation when submerged, preferably waterproof to the intended depth of the dive.

4.1.2 A second source of light should also be carried by free divers.

4.2.1 A mask is considered to be a beneficial aid - unless the free diver is reasonably experienced, a mask should be used for cave diving.

4.2.2 Goggles should only be used in the place of a mask for very shallow ducks or dives, as the diver cannot fully compensate for the change of pressure that occurs with increased depth.

4.2.3 A snorkel should not be used or attached to the face mask strap for free diving. It may have an application for moving along water-filled passage only where there is overhead air space.

4.3.1 Fins are also considered to be a beneficial aid as they increase the diver's stability and propulsion whilst underwater. They may be omitted for short and/or restrictive free dives.

4.4.1 Wetsuits can also be used to provide insulation to reduce body heat loss when immersed in water (see also 4.4.2).

4.4.2 A weight belt should be considered if using a wetsuit (or other buoyant device), so that the diver can maintain neutral buoyancy for the dive - this is especially important if full wetsuits are used.

4.5.1 Dry or semi-dry suits may be used in place of a wetsuit, as in 4.4.1.

5. Signals

5.1.1 A method of signalling the next diver should be determined if a party of cavers is to pass through a sump.

5.1.2 If no other signalling method is to be used, the following line signals should be adopted:

(i) One tug - repeated every 10 seconds until acknowledged. To be used to signal `sump clear' or in reply, `I'm ready to enter sump'.

(ii) Two tugs - repeated every 10 seconds until acknowledged. To be used to signal `stay put - I am returning' or in reply `I will stay put'.

(iii) Three or more tugs -'I need help'.

5.2.1 If paying a line out to a free diver, the following signals are to be used in addition to

5.1.2:

(i) Continuous pull -'pay line out'.

(ii) Slack line -'take line in'.

6. Competence and Experience

6.1.1 Free diving is a potentially dangerous activity and must be treated with respect.

6.1.2 Consideration must be given to a call-out procedure to properly trained and equipped cave divers in the event that overdue free divers do not return or are trapped by increased water levels.

6.2.1 No person should attempt to free dive in a cave unless reasonably competent in water with another water-related activity or sport eg. snorkel, diving, surfing, etc.

6.3.1 If a person has no previous free diving in caves experience, then a training program should precede their first dive (see 6.3.2).

6.3.2 The following should be handled with ease before considering your first free dive into a cave:

(i) Follow line through underwater obstacle course.

(ii) Using blackouts to simulate silting.

(iii) Practise using and not using aids, as in Section 4 - Equipment.

(iv) Practise use of signals, as in Section 5 - Signals.

6.4.1 Consider the experience or inexperience of others if in a caving party about to attempt a free dive.

6.4.2 Remember, a clear sump will silt when the water is disturbed eg. by a free diver entering or moving through the water. This will make a return or a subsequent free diver's pass much more difficult.