Solo diving is the practice of underwater diving without a "dive buddy", particularly with reference to scuba diving, but the term is also applied to freediving. Surface supplied diving and atmospheric suit diving are single diver underwater activities but are accompanied by an on-surface support team dedicated to the safety of the diver, and not considered solo diving in its truest sense.
Solo diving has been in existence for millennia as evidenced by artifacts dating back to the ancient people of Mesopotamia when humans dove for food and collected pearl oysters. It wasn't until the 1950s, with the development of formalised recreational dive training, that recreational solo diving was considered dangerous, particularly for beginners. In an effort to mitigate associated risks, some scuba certification agencies incorporated the practice of buddy diving into their dive training programmes. Some divers, typically those with advanced underwater skills, prefer solo diving over buddy diving and assume responsibility for their own safety. Professionally, solo diving has always been an option as it applies to operational requirements and risk assessment. It customarily involves voice or line communications from diver to surface, usually with a diver at the surface on standby ready to assist on short notice. Recreational divers seldom have such options available.
The recreational solo diver uses enhanced procedures, skills and equipment to mitigate the risks associated with not having another diver immediately available to assist if something goes wrong. The skills and procedures may be learned through effective methods with appropriate competence, including formal training programmes with associated assessment and certification. Recreational solo diving, once discouraged by most training agencies, has been accepted since the late 1990s by some training agencies that will qualify experienced divers skilled in self-sufficiency and redundant backup equipment.
Solo diving is defined as a dive planned to be conducted entirely or partly without a buddy. It may also apply to dives that begin with a buddy but continue after separation, and to dives where other divers are nearby but are neither responsible for the safety of the solo diver, nor competent to deal with the consequences of a foreseeable contingency. The term has also been used to define dives where buddies are insufficiently attentive or close enough to function effectively as a buddy pair, a situation more commonly referred to as "same ocean buddy diving".
The history of solo diving stands in stark contrast to the relatively new concept of buddy diving that was developed for recreational diving in the early to mid-20th century. Artifacts dating back some 4,500 years provide evidence of solo diving for food and commerce by the ancient people of Mesopotamia. There are written accounts from 2nd century BC that describe commercial sponge fishing, including notes about sponge divers, their lifestyle and fear of predatory sharks. In 350 BC, Aristotle wrote about "an ‘elephant nose‐like tube’ that allowed sponge fishermen to breathe during diving", and in 8th–6th century BC, there are references to solo diving in the writings of Homer.
Freedivers traditionally dove alone or with an attendant on the surface to assist with the harvest; many of the early diving bells were only large enough for a single occupant. When surface supplied diving was first developed, it was common to have only one diver unless the work required more. Those early traditions continue and customarily include a standby diver, and a working diver who is in constant communication with the surface control crew. The sport of scuba diving is rooted in a multitude of small enthusiastic snorkeling and spearfishing clubs that date back to the decades just before and after World War II.:ch.12 In the late 1940s, after the invention of the Aqua-lung by Cousteau and Gagnan, the first retail underwater breathing apparatus for sport was commercially marketed. As the sport expanded through the 1950s, several sporting organisations – notably the Young Men's Christian Association (YMCA) – began scuba training programmes for swimming enthusiasts, thus began the codification of what was believed to be proper practices for the expanding amateur sport of scuba diving.:292–295 The buddy system was thought to be a useful corollary to the "never swim alone" edicts of the YMCA swimming and lifesaving programmes. Cousteau independently implemented a buddy system after a number of harrowing diving incidents that date back to the earliest days of exploratory diving. The buddy system's useful aspects have long been established, including the cross-checking of equipment before dives, the facilitating of assistance for possible entanglement problems or equipment failures, and enhancement of the social nature of diving. The YMCA was a substantial influence in the development of diver certification during the first 50 years of the sport. As various scuba programmes were adopted by emerging scuba certification agencies, such as the National Association of Underwater Instructors (NAUI), Professional Association of Diving Instructors (PADI), and British Sub-Aqua Club (BSAC), the practise of buddy diving inspired one of the two main mantras of recreational scuba: "never hold your breath" and "never dive alone".
By the early to mid-1990s, solo divers became more visible and increasingly open about their alternative dive safety philosophy, despite the recreational industry's established adherence to the buddy system. It wasn't until 2001 that SDI initiated formal certification training specifically for solo diving. Several other agencies eventually followed suit with certificates titled Self-reliant Diver and variations of that theme; all with the intention of improving diver competence without necessarily going solo, and recognising that the buddy system does not always comply with the ideal. At the 2012 "Rebreather Forum 3", a significant minority of attendees were of the opinion that, in some circumstances, it would be acceptable to dive solo on rebreathers.
Reasons for solo scuba diving
The intention of using the buddy system when scuba diving is to improve the chances of avoiding or surviving accidents in or underwater. Diving together in close groups of two or sometimes three divers, and cooperating with each other to help or perform a rescue in an emergency situation may save a life; however, it is most effective when each buddy is competent in all the relevant skills and remain consistently and sufficiently aware in order to respond in time.
Some divers, such as instructors, are effectively acting as self-sufficient divers because they dive with students who may not yet be trained in or capable of rescue. Others, such as underwater photographers and videographers, dive solo as it allows them to focus more on capturing selected images rather than relying on buddies to remain close at hand. Photographers or videographers who dive with buddies are often effectively "same ocean" buddies, implying they may be far enough apart physically, or sufficiently focused on their camera-related tasks, to be ineffective as a designated dive buddy. This practice has led to many highly experienced underwater photographers diving solo since they don't commit to provide timely support to a buddy nor expect such support from a buddy. Underwater hunters often elect to dive solo in order to focus on their prey.
Solo diving was considered technical diving by most recreational diver certification agencies and discouraged as more dangerous than buddy diving, but many experienced divers and some certification agencies consider it an acceptable practice for suitably trained, equipped, and competent recreational divers; some others consider it occasionally inevitable. In place of relying on the buddy diving safety system, solo divers try to be self-sufficient and are willing to take responsibility for their own safety while diving. The first training agency to offer a Solo Diving certification was Scuba Diving International (SDI) in 1999. In 2011, the Professional Association of Diving Instructors (PADI) started offering a solo specialty called "Self-Reliant Diver", which in many respects (entry requirements, for example) is very similar to the course offered by SDI.
In professional diving, solo diving is normal procedure when one diver is sufficient to perform the required task, particularly on surface supplied equipment, to the extent that it is not even noted as an exception. However, a standby diver is required at the surface or at the bell, and the working diver must be in communication with the supervisor at the surface. Procedures for the dive are based on assessed risk.
In recreational diving, solo diving is an option chosen by the diver, for any combination of several reasons.
- Solo divers don't need to work around a buddy's diving schedule, and can dive when no trusted and familiar buddy is available.
- Some divers will dive in a buddy pair if diving with a known and trusted buddy but otherwise dive solo in preference to being paired up with a potentially unreliable, incompetent, or otherwise dangerous partner. In the United States, the added risk of becoming a respondent in litigation in the event of a diving accident with such a "dangerous buddy" can be a motivation to dive alone.
- The diver may simply prefer to dive alone. Diving professionals Wes Skiles and Ken Loyst, among others, take pleasure in the solitude of solo diving and in the feeling of self-sufficiency for this style of diving, that one is not dependent on others, but is relying solely on one's own skills and capabilities. Other experienced professionals, including Bret Gilliam and Darren Webb, enjoy the sense of freedom, of not being impeded by the need to look after anyone but oneself and therefore being able to achieve one's own goal in the dive without compromising.
- There are divers who enjoy specific underwater activities but are unable to find anyone who shares the specific interest sufficiently to dive with them, and where the activity is incompatible with a less than dedicated buddy. The option of simply not diving is not a practical solution, as the diver is then almost permanently prevented from pursuing the interest. Diving with buddies who get bored or tired quickly also does not lead to enhanced enjoyment for either party. When the underwater activity is of interest only to one person, diving solo is the only option that allows the activity to be undertaken.
- When photographing or shooting video of shy animals which are easily disturbed, it is more likely to be successful if there is only one diver potentially disturbing the subjects. The disturbance can also be reduced by buddy diving on rebreathers, which cuts down on bubble noise, but at the cost of increased risk due to the inherently higher number of failure modes characteristic of rebreathers. It is not clear which system has the lower overall risk.
- Most scuba depth records are set by solo divers. There is usually a substantial backup team on site and standing by, but for the record breaking part of the dive, the diver is almost always alone, and beyond the reasonable expectation of rescue.
Disadvantages of the buddy system
Scuba diving is done in a hostile environment for which humans are not adapted, breathing from a portable and limited capacity life support system. Under these conditions fatality is always a possible outcome, as even simple equipment or procedural problems can be mishandled. In dealing with this reality a number of major concerns about potentially inherent flaws or negative impacts that can exist within the buddy system have been identified. Few, if any, of these problems are defects in the concept of the buddy system, they are problems with the application of the system.
The amount of discipline, effort and attention needed from both divers in a buddy pair, and the even greater input required in a three diver team, is unattractive to a confident diver who has other things to do during a straightforward, low risk, recreational dive, and the system is undermined when any one of the divers fails to put in the effort, putting the burden on the remaining diver who takes the responsibilities more seriously. Familiarity with the environment, and the very low incidence of life-threatening accidents is likely to lead to a confidence that there will not be a problem on any given dive, so the divers may pay less attention to good buddy practices, and this may become habitual. This may be exacerbated by the divers being strangers thrown together by chance and the whims of the divemaster, who have no real interest in each other, and whose reasons to dive may be incompatible. Pairing an explorer with a macro photographer will annoy at least one, probably both, if they comply with recommended buddy diving practices. Many nominally buddy dives effectively become solo dives soon after entering the water, with the buddies occasionally checking for the presence of each other and often being beyond direct view of each other. In spite of this, very few of these divers die as a consequence.
Critics of the buddy system state that the proponents project the image of a "totally reliable buddy" that does not generally exist in reality. Some buddies lack skills or experience and some are unfit, and some personality types are outright dangers; these types have been described as "the untrained diver", "the high-flyer", "the falsely confident diver", "the angry diver", "the buddy from hell" and several others. The bad buddy problem is compounded by training that pressurises the diver to "stick with his buddy" at all times, leading to the situation that the bad buddy sets the criteria of how (badly) the dive is carried out. The solo diver avoids this problem altogether.
Risks and their mitigation
There has been much disagreement over the relative safety and merits of solo diving. Up to 2003, very few statistics existed regarding the impact of solo diving on safety, as the subject had not been specifically studied. A 2006 report from the British Sub-Aqua Club (BSAC) concluded that "BSAC currently takes the view that based on evidence from available statistics and risk assessment, the increased risk attendant to allowing planned solo diving is unacceptable". The data underlying the statistics which are used to point to the dangers of solo diving are questionable: for example, divers who end up dying alone but originally had started out as part of a buddy pair are often considered to be "diving solo" in such statistics, but whether the separation was a consequence of the triggering incident rather than a cause is not analyzed.
In actuality, studies show that with fatal buddy diving incidents, 57% of deaths happened after the buddy pair had separated from one another during the emergency. Again, these cases could be attributed to failure of the buddy system rather than failure of any solo diving/self sufficient diving system. A further complication in such statistics is that certain more dangerous diving practices (e.g. cave diving) are frequently carried out solo. Therefore, it is questionable whether a death in these circumstances should be attributed to solo diving or to cave diving. Analysis of the figures used by BSAC to categorise solo diving as dangerous shows that during 2001–2008 all but one of these "solo diving deaths" were actually paired buddy divers that became separated during or before the fatal incident (75%) or else were divers diving far outside of the limits set by both SDI and PADI for the practice of solo diving (20%) (i.e. actually deep divers, rebreather tech-divers, and/or cave divers). Two further "solo-diving deaths" were not scuba divers at all, but snorkelers.
In almost all circumstances, two highly competent, totally self-sufficient divers diving a specific dive profile as a buddy pair are at lower risk than those same two divers diving exactly the same profile separately, but this raises the question "how often do normal buddy divers both really fit into this particular description?" When considering the risks in solo diving the alternative risks found predominantly in buddy diving need also be considered. The greatest danger to sports divers is inexperience – 60% of all diving fatalities involve divers having less than 20 completed dives. The buddy system itself can be a source of risk – a 2006 survey showed that 52% of buddy divers were at some time actually endangered by a buddy's behavior or actions.
While there are hazards specifically associated with solo diving, most of these can be planned for and their consequences mitigated by the use of appropriate equipment. In technical diving, where redundancy of critical equipment is standard policy, self-sufficiency is emphasised and taught more extensively than in recreational diving. This philosophy should also be followed by solo divers. A solo diver operating beyond the range for acceptable risk for a controlled emergency swimming ascent needs to carry a second, independent source of suitable breathing gas, which includes a regulator and preferably a submersible pressure gauge. This emergency gas supply typically takes the form of a pony bottle, or for more demanding diving, a twin tank set with the capability of independent operation of each tank. Additional equipment carried may include a backup dive computer, a backup dive light and a backup dive mask. The diver must be familiar with the equipment configuration used and be able to access the equipment easily if it is needed. A solo diver needs to be particularly aware of overall personal fitness and health and the limitations it may impose on their ability to manage an emergency. Finally, the solo diver may dive a more conservative dive plan than he or she might dive with an equally competent buddy diver.
As part of mitigating risks in solo diving the following specific practices have been adopted by SDI for solo diving or are key recommendations by Robert Von Maier—author of the 1991 book Solo Diving: The Art of Underwater Self-Sufficiency:
- All solo diving is to be done within recreational dive limits (no deep, decompression, penetration, or rebreather dives while solo).
- No dives which significantly exceed one's personal experience limits are to be undertaken while solo
- No solo dives are to be undertaken in areas where there are known hazards of entanglement/entrapment
- Solo dives will only be undertaken to depths at which the bailout system used carries an acceptable level of risk, the appropriate equipment is carried, and where the relevant bailout procedures have been practiced successfully by the diver.
- The solo diver's maximum distance to point of exit (shore, boat) will never exceed a distance that can be easily and comfortably swum at the surface in full scuba gear – and the diver will maintain and exercise his/her navigational practices in solo dives to ensure that this is the case.
The core objective in training to be a solo diver is to become as self-sufficient and self-reliant as possible, to be able to deal with any reasonably foreseeable problems without assistance, and to have the competence, fitness, discipline, skills and equipment that will achieve this result. This requires competence at risk-assessment and the ability to plan dives and select equipment that limit the risks. An additional benefit of these disciplines is that they will improve the safety of buddy diving whenever the competent solo diver pairs up with another diver in a buddy team by reducing the risk of the second diver being exposed to an emergency which they may not be capable of managing. Agencies training solo divers also recommend the self-sufficiency training in their courses for all divers as their diving experience grows, so as to achieve greater safety in all diving—buddy and solo.
Training and equipment
To be safe, solo divers must be self-sufficient, well trained, prepared and practised. They should have a completely redundant set of all life support equipment – a complete, self-contained backup breathing gas supply sufficient to return to the surface from any point of the planned dive profile. In addition, the responsible solo divers adhere to a very conservative dive profile, both in depth and level of difficulty. Unlike the buddy system, which encourages divers to rely on others in the event of an emergency, solo diving encourages divers to prepare themselves to overcome emergencies by their own means. The divers who engage in solo diving are typically those who are experienced and equipped enough to handle problems themselves. Solo divers must feel totally comfortable and relaxed in doing this sort of diving, and nobody should ever think of doing diving solo if they are not both competent and comfortable in doing so.
Qualifications for formal solo diving training as provided by SDI emphasises the need for experience and maturity in diving. In particular the student prerequisites for the solo diving certification course are:
- A minimum age of 21 years
- A minimum certification of SDI/PADI Advanced Open Water Diver (or equivalent)
- Proof of a minimum of 100 logged open water dives.
- Depending on the country – a certificate of medical fitness to dive
Besides competence in the standard set of scuba skills, there are a few more advanced self-reliance and self-rescue skills required by some of the training agencies. The diver should be able to select and correctly use all equipment needed for the dive, including self-extrication gear for cutting loose from entanglement.
The diver must have an acceptable alternative air configuration, redundant gauges and/or computers, DSMB and reel, compass, and (depending on training centre) signaling device and line cutting device. During the course tests are conducted on swimming skills and swimming endurance, scuba skills associated with solo diving (e.g. use of redundant air and bailout to emergency gas supply), navigation skills and dive planning skills (including breathing gas management).
The CMAS Self-Rescue Diver training includes the deployment of colour-coded DSMBs – red for position indication, and yellow to indicate a problem – the use of a ratchet dive reel to control ascent rate in the event of unplanned positive buoyancy due to loss of weights, and the use of a backup mask.
Certifications in solo and self-reliant diving
- CDG – Cave Diving Group – The UK organisation prepares divers for solo cave diving in sub-optimum conditions as part of their cave diving skills requirement.
- CMAS – (Confédération Mondiale des Activités Subaquatiques) – Self-Rescue Diver: prerequisite – Two star diver.
- DIWA – (Diving Instructor World Association) – Self-reliant diver: prerequisite – Advanced open-water diver.
- SDI – (Scuba Diving International) – Solo diver: prerequisite – SDI Advanced Diver or equivalent
- IANTD – (International Association of Nitrox and Technical Divers) – Self-sufficient diver: prerequisite – IANTD Deep Diver or equivalent.
- PADI – (Professional Association of Diving Instructors) – Self Reliant Diver
- "A Brief History of Diving: Free Divers, Bells and Helmets - Scuba Diving - Dive Training Magazine". Scuba Diving - News, Gear, Education | Dive Training Magazine. Retrieved 2018-09-13.
- Halstead, Bob (September 1997). "Assume the risk and take the blame" (PDF). SPUMS Journal. 27 (3): 153–4. Retrieved 10 November 2017.
- Lewis, Steve. SDI Solo Diver Manual. Scuba Diving International.
- Lonne, Torben. "Solo Diving: Would You?". Safety in diving. DIVE.in. Retrieved 23 February 2017.
- "Learn more about diving alone". DIVE.in. 2011-07-11. Retrieved 2018-09-23.
- Francis, John (19 October 2006). "Buddy System Breakdown". Scuba diving. Retrieved 15 October 2017.
- Layton, Rick (15 July 2012). "When The Buddy System Fails". DAN Europe. Retrieved 15 October 2017.
- Tony Booth (6 October 2007). Admiralty Salvage in Peace and War 1906 – 2006: Grope, Grub and Tremble. Pen and Sword. p. 9. ISBN 978-1-78337-470-0.
- Pronzato, Roberto; Manconi, Renata (2008). "Mediterranean commercial sponges: over 5000 years of natural history and cultural heritage". Marine Ecology. Wiley. 29 (2): 146–166. doi:10.1111/j.1439-0485.2008.00235.x. ISSN 0173-9565.
- "Diving Regulations 2009". Occupational Health and Safety Act 85 of 1993 – Regulations and Notices – Government Notice R41. Annexure B – Minimum manning levels. Pretoria: Government Printer. Archived from the original on 4 November 2016. Retrieved 3 November 2016 – via Southern African Legal Information Institute.
- Dugan, James (1965). Man Under the Sea. Collier Books. Library of Congress Number: 64-18390
- Hanna, Nick (2006). The Art of Diving. Ultimate Sports Publications. p. 107. ISBN 0-9545199-2-2. Archived from the original on September 13, 2011.
- Brennan, Michael (1970). Underwater Swimming. Mayflower Books. pp. 49–52. ISBN 978-0-583-19608-6.
- Brylske, Alex (1994). "Solo Diving: Perspectives on going it alone". Dive Training magazine. Retrieved 5 April 2018.
- Taylor, David (19 October 2006). "Solo Certification: It's Time". Scuba Diving magazine. Retrieved 5 April 2018. Originally published in Rodale's Scuba diving: An interview with Brian Carney, Training Manager, Scuba Diving International.
- "Self-Rescue Diver Training Programme". CMAS. Retrieved 12 April 2017.
- Staff (2016). "PADI Self-Reliant Diver". Distinctive Specialty Courses. Professional Association of Diving Insructors. Retrieved 22 February 2017.
- Staff (2010). "IANTD Self-Sufficient Diver (OC, SCR, CCR)". IANTD Tek Lite Programs. IANTD. Archived from the original on 4 June 2016. Retrieved 2 May 2016.
- Mitchell, Simon J. (18–20 May 2012). Vann, Richard D.; Denoble, Petar J.; Pollock, Neal W. (eds.). Rebreather Forum 3 Consensus (PDF). Rebreather Forum 3 Proceedings. Durham, North Carolina: AAUS/DAN/PADI. pp. 287–302. ISBN 978-0-9800423-9-9.
- Halstead, B (2000). "Line dancing and the buddy system. reprinted with permission from Dive Log 1999; 132(July): 52-54". South Pacific Underwater Medicine Society Journal. 30 (1). ISSN 0813-1988. OCLC 16986801. Retrieved 2008-09-05.
- Powell, Mark (October 2011). "Solo Diving—Coming out of the Closet". Seminar: Dive 2011 Birmingham. Dive-Tech. Retrieved 18 August 2016.
- DAN SA Legal Team (23 June 2016). "Waivers, Children & Solo Diving". Legal tips. Divers Alert Network South Africa. Retrieved 4 December 2016.
- Von Maier, Robert (2002). Solo Diving, The Art of Underwater Self-Sufficiency (2nd ed.). Aqua Quest Publications. p. 128. ISBN 1-881652-28-9.
- Staff (4 March 2014). "CMAS Self-Rescue Diver". Standard Number: 2.B.31 / BOD no 181 ( 04-18-2013 ). CMAS. Retrieved 13 April 2017.
- Brian Carney, ed. (2011). SDI Solo Diving Manual (2nd Revised ed.). Scuba Diving International. pp. 13–18. ISBN 978-1-931451-50-5.
- Coleman, Phyllis G. (2008). "Scuba Diving Buddies: Rights, Obligations, and Liabilities". University of San Francisco Maritime Law Journal. 20 (1). Retrieved 2011-08-14.
- von Maier, Robert (1991). Solo Diving: The Art of Underwater Self-Sufficiency. Watersport Publishing. pp. 88–89, 95. ISBN 0-922769-13-3.
[Wes Skiles:] The second primary reason I solo dive is to be alone, to be with myself and the underwater environment ... I enjoy facing fear and anxiety alone. When I do so successfully I feel more alive, more in control of myself ... [Ken Loyst:] There is a degree of pleasant solitude while diving alone.
- von Maier, Robert (1991). Solo Diving: The Art of Underwater Self-Sufficiency. Watersport Publishing. pp. 80–81, 91. ISBN 0-922769-13-3.
[Bret Gilliam:] [In some situations] I prefer to dive solo and not bear the responsibility for another diver's safety. This allows me more personal and professional freedom in the circumstances of the dive and I derive more pleasure from the experience ... [Darren Webb:] Why solo dive? Because I'm not forced to depend on or be responsible for a dive partner. This extra freedom allows time to concentrate on just me and my objectives.
- Lord, Jenny. "Job Profile: Deep Support Diver". divemagazine.co.uk. Retrieved 10 November 2017.
- Mueller, Brandi (15 November 2015). "Solo Diving". Opinions Articles from X-Ray Mag. X-Ray Mag. Retrieved 23 February 2017.
- Halstead, Bob. "On Your Own: The Buddy System Rebutted" (PDF). Anaspides.net. Retrieved 18 August 2016.
- Caruso, JL; Uguccioni, DM; Ellis, JE; Dovenbarger, JA; Bennett, Peter B (2003). "Buddy versus solo diving in fatal recreational diving accidents". Undersea and Hyperbaric Medicine. Undersea and Hyperbaric Medical Society. 30 (1 supplement). ISSN 1066-2936. OCLC 26915585. Retrieved 2008-07-23.
- BSAC. "BSAC Talk – Solo Diving". Retrieved 2011-06-04.
- Edmonds, Carl (2010). "4: Why Divers Die". Diving Medicine for Scuba Divers (3rd ed.). ISBN 978-0-646-52726-0.
- Elliot, D.; Bennett (1993). Underwater Accidents, The Physiology and Medicine of Diving (4th ed.). W.B. Saunders. p. 240.
- Coutanche, Andrew Philip (2006). "Does the buddy system really make recreational scuba diving any safer?" (PDF). Chilterns University College Thesis: 31. Retrieved 2011-08-14.
- Staff (1 January 2018). "Solo Diver" (PDF). SDI Instructor Manual - Specialties Standards Version 18.0. Scuba Diving International. pp. 75–78. Retrieved 15 October 2017.
- Gurr, Kevin (2002). Technical Diving from the Bottom Up. Periscope Publishing. p. 19. ISBN 1-904381-20-0.
- "Cave Diver Education & Qualification". www.cavedivinggroup.org.uk. Retrieved 26 February 2019.
- Staff. "Education system". Diving Instructor World Association. Retrieved 30 September 2013.
- Staff. "Solo Diver course". Scuba Diving International. Retrieved 30 September 2013.