BSAC Technical Publications - Safe Diving Practices Q-Z LEARNING TO DIVE MEMBER SERVICES TECHNICAL SERVICES FORUMS BSAC WORLD SNORKELLING MAIL SHOP NEWS TECHNICAL SERVICESSearch the BSAC Site: sitemap BSAC TECHNICAL PUBLICATIONS SAFE DIVING PRACTICES Q-Z A-C | D-H | I-P | Code of Conduct | Rebreathers Qualifying Dives Open water qualifying dives should be made under the guidance of a Branch instructor or approved Dive Leader. Each dive should increase the diver's experience of differing underwater conditions and where appropriate follow the format laid out within the training scheme. Rebreathers BSAC only recognises CE approved semi-closed (SCR) and closed circuit (CCR) rebreathers for use within BSAC branches for recreational diving and training. At present the following rebreathers are approved: Draeger Atlantis, Dolphin and Ray Ambient Pressure Diving's Inspiration The BSAC Rebreather Working Group (RWG) will continue to evaluate any new rebreathers that receive CE approval and are intended for general distribution to the recreational market. Consequently, new rebreathers could be added to this list - BSAC HQ will have information on any additions to this list. Members wishing to use a rebreather for recreational dives in BSAC branches must hold a recognised rebreather user qualification and register this qualification on the BSAC Rebreather Database with Technical Support Services at BSAC HQ. Currently the BSAC only recognise the Entry Level rebreather courses provided by the Technical Training Agencies (i.e. nitrox breathing gas to 40m max.). Current BSAC recommendations for Safe Diving are equally applicable to diving with a rebreather. Rebreather divers should also follow the additional guidelines for diving rebreathers that BSAC have published called "Rebreather Safe Diving". A subset of those rebreather diving guidelines is provided below; The maximum depth for rebreather diving within BSAC is 40m CCR rebreather diver should be a minimum of Sports Diver with advanced nitrox qualification SCR rebreather diver should be a minimum of Sports Diver with nitrox qualification Buddy of a rebreather diver (whether SCR or CCR) should be, as a minimum, an experienced Sports Diver with their DO's consent The DO (or DM acting on behalf of DO) should ensure that the Sports Diver (or above) who will buddy a rebreather diver is; experienced under the current diving conditions (i.e. site and weather) capable of recognising the conditions of hyperoxia, hypoxia and hypercapnia capable of performing a rescue (CBL and surface support) on the rebreather diver in the case of an emergency The Dive Marshal (or Deputy) should be an Advanced Diver with a nitrox qualification The dive plan should suit both divers and represent the most conservative case of dive profile required by the two divers. The dive plan should be communicated to the Dive Marshal The rebreather diver and the buddy must each carry adequate bailout for the dive to be undertaken. For dives deeper than 20m the rebreather diver should consider the use of an independant bailout in addition to the 2L or 3L bailout cylinder provided as an integral part of the rebreather. The rebreather diver and buddy should each carry a DSMB and at least one other surface location aid. The buddy check should be modified to incorporate the layout of the rebreather & ensure the buddy can operate the rebreather mouthpiece in case of a rescue. All diver training and teaching wearing a rebreather should be conducted in accordance with the guidelines published in 'Rebreathers in BSAC Training'. The use of a rebreather in First Aid measures following a DCI incident within the diving party should be considered once the oxygen cylinder in a standard oxygen administration set has been depleted or no other source of oxygen is readily available. Further guidance on the use of rebreathers in rescue management will be available within the revised Dive Leader Training of the new Diver Training Programme. Since 1st January 2002 BSAC has enabled the use of planned decompression when diving a rebreather for up to a maximum planned decompression of not more than 10 minutes and stop depth(s) not deeper than 6m. In all cases, the planned decompression should not exceed that permitted by the unit manufacturer and/or the Training Agency certification held by the rebreather diver. In addition BSAC recommend that; The decompression should be planned and conducted using an appropriate decompression tool; A rebreather diver planning a decompression dive should have a bailout plan & carry adequate independent bailout to carry out the bailout plan; The decompression planned should be conducted in accordance with BSAC publication Safe Diving and the rebreather diver's Training Agency recommendations; The decompression plan should represent the worst case decompression requirement of the buddy pair in order to ensure there will be no buddy separation during the decompression stop (in case that the rebreather diver needs to bailout). A BSAC publication titled "Rebreathers in BSAC Training" outlines the recommendations for the use of rebreathers in branch diver training and for BSAC events such as Skill Development Courses and Instructor Training Events. All RWG publications are available from BSAC HQ or can be downloaded from the BSAC web site. Re-Entry Decompression If a diver misses planned decompression stops, no attempt should be made to enter the water again in order to complete them. In this situation the diver is increasing the risk of decompression illness. Repeat Dives The BSAC 88 Decompression Tables should be used for planning and performing repeat dives. Where two or more dives are being made the same day, it is good practice to carry out the deepest dive first. You should also take care if you are involved in several days of diving deeper than 30m. It is possible to accumulate excess nitrogen over this period, and apparently 'innocent' dives, carried out near the end of the period of diving, can cause decompression illness. It is therefore recommended that any dive series involving consecutive days diving to 30m+ is limited to three days, after which a 24 hour break should be taken. (See BSAC 88 Decompression Tables). Ropes Divers should take great care with the use of ropes underwater, especially using reels as distance lines from shot lines. Reels for SMB use should float independently, have a quick release system such as a bayonet fitting snap lock and divers should be taught how to use them. When divers do get into difficulties on ascent it is often the best course of action to ditch the reel so that both hands are free to deal with the situation. When using a reel and line as a bottom distance line, we recommend that a reel and line which sinks is used and that when deploying line, hold the reel and line away from the body and especially the legs. It should also be recovered from in front of you. Never let a bight of line develop in front of you; slow down and wind in. Divers should always carry an adequate knife, especially when dealing with ropes. Separated Divers If divers become separated underwater, a brief attempt (approx. 30 seconds) to re-locate should be made, after which the divers should surface. If the dive is subsequently re-commenced appropriate decompression planning must first be carried out. Sharing See Assisted Ascents. Signals Divers should be completely familiar with the standard code of visual signals and should give them accurately and clearly. All signals should be acknowledged. The 'Come and get me' signal by a diver at the surface is to be used only for distress, and not as a 'Pick me up' signal. Solo Diving There are occasions, e.g. in nil visibility or when working underwater, when the 'buddy' system is ineffective. On these occasions a solo dive may be required, with the diver being securely roped and in constant rope communication with a surface 'tender', who should be a diver themself. The rope must be securely fastened to a suitable object on the surface. Communicating signals must be fully understood and a fully kitted, roped, 'stand-by' diver must be available in the event of an emergency. Stand-by Divers On the majority of dives your stand-by diver is your buddy. A stand-by diver is usually only required when a solo dive, using a rope tender, is in operation. Surface Marker Buoy (SMB) SMBs should be used in significantly moving water, when operating well off shore and in areas with heavy surface traffic. There may be times, other than these stated, when their use might be deemed prudent by the dive marshal. It is essential that correct training is given to new members in their use, as for any unfamiliar equipment. In some situations e.g. wreck sites with slack water, they are unnecessary and can actually be a hazard to the diver. Tangle Nets/Gill Nets Indiscriminate fishing, particularly on wreck sites, with difficult-to-see monofilament netting, is a real hazard around the British coast. Experiments have shown that the average diver's knife is very ineffective should the diver become entangled. A line cutter or a curved blade 'dinghy' knife, with a blunt end, are probably the most effective for this purpose and need to be worn on the arm. A knife with a sharp point could lead to a diver stabbing himself when in difficulties. Small shears or scissors are recommended as an effective tool for cutting netting. Once caught in netting, it is advisable to partially inflate your BCD, so you rise inside the net, putting it under tension and making it easier to cut. The positive buoyancy will also help to 'tear' you away. If your buddy is free of the netting they may be advised to cut you out, still enmeshed, and worry about completing the job on the surface. Tides The success of any sea dive depends on accurate, local, tidal predictions for the dive site you wish to visit. Admiralty charts give accurate large scale predictions and should be used in conjunction with the relevant local tide tables. Tidal Stream Atlases are also useful and are available for the UK and many other sea areas throughout the World. Trimix Trimix is a mixture of three gases, Oxygen, Helium and Nitrogen in various percentages. (See Mixed Gas). VHF Radio VHF radios are a valuable aid to safety at sea and, together with suitable waterproof housings, are frequently used in small boats. Radios should be licensed and, under normal circumstances, should only be used by, or under the supervision of, someone who holds an appropriate Certificate of Competence. It is an offence to use Marine VHF radio from the land, (unless it is a registered land station) so your shore party is not allowed to use one. Weather Acquiring an accurate weather forecast for your dive site can save a lot of unnecessary travelling expense and can mean the difference between a controlled successful dive and a risky experience. BBC TV News Bulletins are always followed by a UK forecast with easy to understand symbols. Some daily newspapers carry a good forecast with weather map, and the Maritime and Coastguard Agency always has an up to date forecast. RAF stations have a meteorological station and are usually very helpful. The Shipping Forecast on Radio 4 is another very useful source, whilst the Meteorological Office (Met Office) provides a telephone message and fax back service: its helpline is 0845 300 0300. Weightbelts/Integrated Weight Systems Weightbelts or integrated weight systems, when used, should always be fitted with a reliable quick release and fitted so that they will always fall clear of other equipment when released. You should be practised in releasing your weights and should also make sure that your buddy is well briefed and fully familiar with your release mechanism. If the buckle is of the same type as on the cylinder harness, it is wise to wear it so that it operates in the opposite direction. Wreck Diving Wreck diving is one of the most popular forms of diving and requires extra safety precautions if divers venture inside the wreck. Many steel wrecks are in a dangerous state of decay, and loose overhead objects or steel plates are a real hazard. Never venture deep inside a wreck without ensuring your route to clear water is certain, and use a reel and line secured to the outside of the wreck to mark your return route. Avoid excessive finning inside a wreck as sediment stirred up is very slow to settle, due to lack of tidal flow. Always allow an adequate reserve of air at the end of your dive and never run down your air supply by attempting to remove an artefact. Never try to lift heavy objects from wrecks using your BCD and/or drysuit. Underwater ordnance can be very unstable and should not be recovered. It is a criminal offence to be in possession of explosives without the relevant licenses. See Diver's Code of Conduct A-C | D-H | I-P | Q-Z OTHER BSAC TECHNICAL PUBLICATIONS ©2003 BSAC | Home Page | Member Services | Technical Services | News