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Clarification statement on Alternative Supply training and going diving

Important information for BSAC Instructors and Diving Officers

Jeff Reed, National Diving Officer, March 2010

Clarification Statement on Alternative Supply training and going diving

This document details the policy and recommendations of BSAC with respect to the various techniques and configurations for Alternative Supply for another diver while both diving and teaching diving. 

(You can also download a PDF version of this statement)  

The National Diving Committee (NDC) has the responsibility to ensure that training in Alternative Supply (AS) techniques is delivered consistently and to appropriate standards, in particular for inexperienced divers. We are concerned that inconsistency in the Alternative Supply technique taught to divers may lead to confusion and this is potentially dangerous. It is important that instructors teach to the current syllabus only and, where instructors have personal preferences for other techniques, they should not introduce them into the BSAC Diver Training syllabus without written approval of the BSAC National Diving Officer.

For gas sharing with another diver, the current recommended techniques have been determined so that they are appropriate for:

• All levels of diver, from those just starting their training to the very experienced

• Open circuit and rebreather divers


In late 2009, the NDC Technical team issued two documents to Technical Instructors regarding the use of two methods of Alternative Supply whilst diving and undergoing diver training with BSAC:

i. Hogarthian Rigging, sometimes referred to as “Hog Wrapping” or “Long Hose Wrapping”

ii. Primary Take and /or Primary Donate methods for use in out of diving gas situations.

The publication of the initial document, first distributed in early December 2009, met with a significant response - both positive and negative - from BSAC members and the diving community at large and resulted in the second document being released to respond to some of the immediate comments received by BSAC. Since the second document publication, responses continue to be received either by direct communication to NDC Technical Group or via the BSAC internet forum. However, it is clear that there continues to be confusion and frustration on this issue. BSAC believe that this is occurring because of misinformation and misinterpretation of the BSAC position.

The purpose of this document is to restate and clarify the BSAC position with respect to the above two points.

BSAC intend that this document stands alone and to avoid further confusion, reference to the previous two communications is not made. Any further revisions or additions to this document will be made through document updates and clarification statements being added into the current BSAC Diver Training system.

In arriving at our recommendations the following sources of information were used:

a. BSAC Diver Training Programme, 2002, updated to Rev 4 and issued on January 1st 2008

b. Consultation with lawyers on the Liability Act (reviewed by an independent team of lawyers on February 3rd 2010)

c. Consultation with the BSAC and independent insurers (on February 6th 2010)

d. BSAC Safe Diving policy and documentation.

e. Analysis of the BSAC incident reports database for the report years covering 1997 – 2009 (BSAC Incidents Advisor / NDO)

f. BSAC Safeguarding policy

g. Articles of Association and Rules of BSAC

Additional Background Information / Comments:

Analysis of BSAC Incident Reports

We analysed incidents report data and determined the following:

a) The most common failure mode of a regulator was free-flow whilst filling a DSMB or lifting bag (i.e. 31 % of the total recorded incidents involving AS). Divers should consider using a crack bottle or air gun to minimise the risk of free-flow.

b) The second most common issue leading to the necessary need to use an Alternative Supply is the diver inhaling water while breathing in from a regulator. This may occur for example due to a regulator failure such as a split diaphragm or a damaged mouthpiece.

c) 21% of recorded alternative supply incidents were due to a diver running out of gas.

d) The most common experience for an out-of-gas diver is that the diver attempts to take a breath, i.e. has breathed out and is breathing in their next breath and there is ‘nothing there’. On many occasions the out-of-gas diver is known to swallow water, causing the out-of-gas diver to gag and rapidly escalating stress levels and panic reactions.

e) We found no evidence that the Alternative Supply techniques currently taught within the BSAC Diver Training Programme are endangering or causing issues for trained divers.

f) There was significant evidence that demonstrated that the training and use of the Alternative Supply technique continues to save lives. In the past 12 years, from over 5,200 recorded incidents, 275 have involved out of gas scenarios that have resulted in positive resolution.

g) Fatalities involving Alternative Supply were found to be a direct consequence of a complex sequence of events, and in many instances we will never know what actually happened. Initiators of an incident included water inhalation, failure of regulator whilst switching, out of gas and entrapment.

In recent years, equipment failures have substantially reduced. Key drivers include better regulator design, tighter manufacturing standards, competition and improved construction materials.

Current BSAC Training

a) The BSAC ideal is to have one common system that allows for reliable and safe gas sharing within a buddy pair. The common system therefore deals with divers using either similar or dissimilar equipment (dissimilar may for example mean an Open Circuit diver paired with a Rebreather diver).

b) BSAC training teaches that all divers have a duty of care to properly maintain their equipment and check and confirm its operation using a buddy check before a dive. BSAC Dive Leader training and above requires that those reaching and holding these grades demonstrate positive ‘role model’ behaviour. We see this as important because of the propensity for less qualified or younger divers to copy the behaviours, actions and kit configuration of those they consider to be ‘senior divers’. BSAC believes that copying unusual practice or equipment configurations without the appropriate training or knowledge may increase risk of harm to the diver and/or their buddy.

c) The BSAC Diver Training Programme takes account of developing trends, equipment configurations and instructional techniques as they continue to evolve. BSAC also analyses the BSAC incident reports to identify important issues and trends. The last significant change BSAC made was the removal of single hose buddy-breathing from core training. The evaluation of incidents and feedback is a continuous process and BSAC will make appropriate changes following evaluation and consultation.

d) The BSAC Diver Training Programme acknowledges that all known equipment configurations have advantages and disadvantages and these will vary depending on the type of diving being undertaken. Hogarthian rigging, for example, appeared as a solution to out-of-gas situations in cave diving (narrow passages) and progressed to wreck penetration diving, and into technical and recreational diving.

e) The BSAC incident reports for the past 12 years do not highlight any increased risk for a diver using an independent twin cylinder configuration when directly compared to manifolded twin set incidents.

f) Equipment configuration is generally not static, as manufacturers develop and sell the next best idea. Divers will tend to try, adjust, discard and move on as these developments occur – this change is for many divers one of the pleasures of the sport. For example, the development of a new clip to retain an Alternative Source (octopus clip) through to the more complex such as the recent integration of a bail out mechanism in the mouthpiece of rebreathers. BSAC does not have a policy of interfering with these developments and works with the diving community to ensure that training keeps pace with the direction in which the sport and diving equipment is heading. We recognise that on occasion, it is incumbent on BSAC to guide our members where we have safety and other concerns.

g) There are some indications in incident reports supported by anecdotal comments from a few commentators suggesting that, in a panic situation, an out-of-gas diver will first grab and take a buddy’s primary regulator from his mouth. Without having substantiated details in incident reports it is considered, for the time being, that such action is arising due to incorrect training at the point of delivery (wherever that may be occurring), incorrect equipment configuration (e.g. the AS is zipped in a BCD pocket and inaccessible), or a hangover from the days where some divers were taught and regularly practiced buddy breathing from a single regulator and they instinctively revert to this learned behaviour in a stressful situation.

h) On behalf of BSAC, NDC carried out studies in open water to examine Long Hose Wrapping and Primary Donate. Through our studies, and by reproducing documented incidents, there was judged to be sufficient concerns for BSAC, BSAC Technical and the National Diving Committee to issue policy statements and clarifications on the position of BSAC divers and BSAC training methods.

BSAC position on Recreational Diving within the BSAC environment

a. The preferred method for kit configuration is detailed in the BSAC Diver Training Programme for diving and instruction:

• The Alternative Supply should be stowed in such a way that in an emergency situation it is clearly identifiable and freely accessible to the buddy, i.e. attached by a quick release mechanism to dive kit and not obscured by other equipment or the kit itself. Stowage refers specifically to the secondary regulator and not the regulator being held in the donor’s mouth. Ease of identification can be enhanced by the use of coloured hoses or second-stage regulators.

b. BSAC advises that divers holding recognised qualifications utilising techniques that differ from the BSAC Diver Training Programme may dive on branch, regional or expedition dives provided they meet their duty of care by fully and clearly explaining to their buddy what the particular technique entails. This should include:

i. A clear demonstration of operation.

ii. The appointed Dive Manager verifies that the divers are comfortable diving as a buddy-pair, prior to entering the water.

Important Note: What is their “duty of care?” This is a legal duty on ‘persons’ imposed by law in the United Kingdom. (It may or may not have the same meaning in other countries in the World). In the UK it is for the courts to decide if a ‘duty of care’ has been met should an incident occur and a ruling is required. Divers are therefore advised to take extreme care over meeting their duty of care in the above situation and introducing different techniques to other divers, especially the inexperienced. BSAC would suggest that one diver simply telling another how their non standard AS system was to be applied, moments before entering the water without establishing that the method was fully comprehended, would not sufficiently meet the duty of care.

c. BSAC reminds all Diving Officers and Dive Managers of their responsibility when selecting and supervising suitable buddy-pairs when diving. The events and contributions leading to this document have highlighted the potential for a very wide range of skills, methods, equipment and training potentially existing between a buddy pair in today’s diving environment.

d. It is recommended by BSAC that divers who use a life supporting technique, eg. Primary Donate, in which they have not been formally trained should seek and obtain a recognised qualification in its application. Insurers and the courts may seek evidence of competency in the event of proceedings or a claim following an incident.

e. BSAC suggests that the ideal scenario is that both divers are trained, competent, familiar and practised in a common and readily used technique. When the technique is new to their buddy, additional time and practice should be taken to familiarise each other in the differences between the techniques and procedures to be followed in the event of an out-of-gas incident. Insurers and the courts may seek evidence of competency in the event of proceedings or a claim following an incident occurring.

f. Under no circumstances whatsoever does the above infer BSAC accepts the introduction of techniques by individual divers that differ from those prescribed by the main training agencies. For example NDC is aware that ‘Primary Take’ methods are being promoted by some BSAC divers and instructors within BSAC Clubs, this is unacceptable to BSAC. History informs us that this leads to unacceptable levels of incidents in training and diving. In the past 12 years, using the current training techniques, there were only three reported incidents where the out-of-gas buddy has deliberately snatched their buddy’s regulator from their buddy’s mouth.

Removing a buddy’s primary regulator in an out-of-gas stressed situation not only affects the out-of-gas diver but will also increase stress levels in the potential rescuer and this could significantly impair a successful resolution to the problem. In the BSAC incident reports we have evidence that fear, panic or extreme stress can cause divers to revert to instinctive learned initial training. Should primary take be accepted or encouraged, this could have severe consequences in an out- of-gas situation whereby there is an increased risk of two casualties. In addition, on expeditions and on holidays a diver may dive with a variety of buddies and in panic may remove another diver’s regulator (not necessarily their own buddy, but that of the nearest diver) and this could not only compromise a rescue but could have severe legal ramifications.

BSAC Position - Technical Diving

a. Technical (and more advanced) diving puts the primary response in an out-of-gas situation on self-reliance, either in switching to an independent Alternate Source (e.g. pony) or own Secondary Source (independent second cylinder or manifolded regulator). The reliance on a buddy in such an out-of-gas situation is SECONDARY to this self-reliance. In a situation where a diver has experienced an out-of-gas situation with bottom gas and has failed in this switch, then going to a buddy for assistance is both secondary AND likely to be in an increased stressful situation.

b. The BSAC incident reports highlight that the donor is at an increased risk of inhaling water whilst accepting a donated regulator, however, incidents involving Technical Divers in out-of-gas scenarios are relatively few (i.e. less than 0.1 %). BSAC believes this is likely to be due to the higher level of training, self reliance, practice and experience held by Technical Divers.

c. The BSAC Technical ‘open circuit’ courses have, since 1998, focused primarily on the importance of self-reliance and the ability of the diver to switch to their own Alternate Source. We recommend that the equipment configuration of the Alternate Source intended for an out-of-gas buddy be located in an accessible position in order to avoid the need for primary donation.

However, certain equipment configurations (including a popular configuration dived by our members, independent twins) require the diver to breathe from both second stages at different stages of the dive. Unless both regulators have a hose length or configuration (e.g. side exhaust or swivel connection) that allows either to be used comfortably by a buddy, then it may be necessary at certain stages of the dive to donate the primary regulator. BSAC’s preference is to completely avoid primary donation, but an appropriate technique should be available within our technical courses to meet the demands of such configurations.

d. The BSAC recommends that in the case of out-of-gas during the decompression phase of a dive, the response should be one of self-sufficiency. The out-of-gas diver should NOT rely on donation of gas from a buddy but switch to their own backup or travel gas as an appropriate breathable gas and they must have a bailout plan that accommodates this. A buddy should NOT be expected to donate their own decompression gas until such time as they have completed their own decompression requirements, unless their decompression gas configuration carries a second regulator specifically for this purpose.

e. Any reliance on the buddy donating, or allowing the out-of-gas diver to 'take' a decompression regulator will destabilise BOTH divers, double the amount of gas switching required and cause BOTH to break their decompression schedule.

f. The BSAC Technical courses do not teach the Hogarthian Wrapping method. BSAC Technical does not mandate the use of manifolded twins with isolator. This configuration is required for the application of Hogarthian wrapping. A proportion of our members attend courses and dive with independent twin set configurations, some with buoyancy compensator devices (BCDs) which do not lend easily to the Hogarthian wrapping method as the diver periodically breathes between primary and secondary regulators and the short hose is not rigged for deployment to their buddy. Many divers prefer a left and right handed regulator method allowing the buddy to share gas from either cylinder. This represents a natural course of development for many of our members. Another consideration is that Hogarthian Wrapping requires all stage cylinders to be attached on the left hand side of the body, to allow for ease and consistency of deployment of the primary regulator. BSAC allows our members the flexibility to dive using the ‘rich is right’ principle, a technique used by the majority of our closed circuit rebreather divers (i.e. 1 in 10 divers today) and many open circuit divers. BSAC Technical Courses are deliberately written for maximum consistency with the core BSAC Diver Training Programme, as potentially any technical diver may be paired with an Ocean, Sports, Dive Leader or Advanced Diver during branch or expedition dives. BSAC does recognise the value of the underlying philosophy of ‘Hogarthian Style’ i.e having a streamlined kit configuration and carrying only equipment appropriate to the particular dive.

g. BSAC Technical Instructors are guided by separate technical diving instructional documentation and subject to stricter quality assurance controls than BSAC recreational instructors.

Instructing on BSAC Recreational Diving Courses

a. The BSAC Diver Training Programme clearly states the technique of training students as both donor and receiver. The instructions for the configuration and technique of teaching ‘Alternative Supply’ are consistent for all of the BSAC diving grades.

Ocean Diver – Basic Skills, states:

"teach for the more real situation of the recipient taking the donor's AS from its stowage”

Sports Diver – Basic Skills review, states:

“takes donor's AS from stowage and commences to breathe from it.”

Dive Leader – Diving and Rescue Skills Review, states:

“takes donor's AS from stowage and commences to breathe from it.”

Advanced Diver – Diving and Rescue Skills Review, states:

“takes donor's AS from stowage and commences to breathe from it.”

b. BSAC insists that BSAC instructors only teach the methods within the BSAC Diver Training Programme current at the time of training delivery.


c. During the process of becoming a BSAC Instructor, divers should have been taught under the guidance of a BSAC Instructor Trainer and some will have been examined on instructing in compliance with this system. The BSAC Diving Instructor qualification is awarded as a direct consequence of proving competence to deliver the core training as detailed in the BSAC Diver Training Programme.

General considerations for all levels of BSAC Instructor

a. By teaching any BSAC syllabus, a BSAC instructor, irrespective of Instructional grade, agrees to comply with and teach the BSAC Diver Training Programme and any corresponding supplementary Skill Development Courses, including BSAC Technical Courses, in line with BSAC Safe Diving practices.

b. Only Instructors who have written approval of the National Diving Officer are allowed to deviate from the defined training materials. This is generally limited to piloting of new techniques and courses.

c. BSAC instruction can only be carried out in a Branch, at regional level or through a BSAC Centre.

d. BSAC membership must be maintained for someone to retain BSAC Instructor status and so be able to instruct on BSAC courses, subject to the previous clause.


When instructing the BSAC Diver Training Programme, an instructor must follow the prescribed techniques in which the instructor has been judged as competent to teach. This applies for all skills.

BSAC Technical Instructors are trained and provided with specific guidance within BSAC Mixed Gas Courses on the use and teaching of alternative techniques that vary from those in the BSAC Diver Training Programme and that are relevant to specific equipment configurations adopted for BSAC technical courses.

Other than when instructing BSAC courses, there is no restriction on diving alternative systems provided that sufficient actions have been taken that would reasonably be expected to meet their duty of care toward a buddy. BSAC recommends that both members of a diving buddy pair have each been trained and qualified in any method they plan to use.

BSAC will not support individual divers introducing their own methods that are outside any of those prescribed by the principal training agencies.

STATEMENT relating to this document, its publication and the events leading to its publication.

BSAC’s National Diving Committee has immense responsibility in this day and age to take the sport of underwater diving forward in a safe and prescribed way that minimises risk and uses the knowledge and experiences gained by its participants for the benefit of all.

The National Diving Committee also recognises that, on occasion, its collective judgement and decision will be at variance with some individuals or parts of the diving community at large. It is acknowledged that some individuals will not agree with the current position that BSAC has stated above.

BSAC has always taken a considered and cautious approach to diver safety. BSAC and the National Diving Committee have never ignored any feedback. Further to this, BSAC training, safety guidance and policies are constantly reviewed and developed over time. Consequently, the National Diving Committee welcomes any contribution to debates within BSAC to enable proper consideration and appreciation of all existing, emerging and new diving methods.

BSAC and the National Diving Committee would like to thank all the commentators who have made a positive contribution to this particular subject over recent months.

To complement this document, BSAC has also issued a sheet of ‘Frequently Asked Questions”. The reading of this document is highly recommended.

BSAC National Diving Committee – March 2010