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JOINT SERVICE ADVENTUROUS TRAINING (JSAT) DIVING
DEFENCE DIVING (Mil) CROSSOVER v2
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Joint Service Adventure Training (JSAT) Sub Aqua Diving
BSAC Centres & individual Branches The British Sub Aqua Club The largest Diving Club in the world Formed 1953
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A BSAC Branch Branch Committee Chairman Diving Officer Treasurer
Secretary Committee Members Training Officer Equipment Dive Manager
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The BSAC - The Organisation
BSAC Members BSAC Branches BSAC Centres BSAC Regional Coaching Team BSAC Headquarters Full time Staff National Diving Committee Responsible for diving, instructing and safety standards Board of elected volunteer Directors known as BSAC Council
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Benefits of BSAC Membership
Largest Diving Club in the World Internationally recognised qualifications Diver Training Materials Scuba magazine (monthly) Free Third Party insurance Member’s Mail Shop Preferential discounts from equipment and holiday companies
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Diver Development within BSAC
Discovery Diver – Reduced training serials than Ocean diver. Qualified to dive to a max of 12m with a Dive Leader under supervision of a Dive Manager Ocean Diver Sports Diver Dive Leader Advanced Diver First Class (Regional preparation courses and exams) Skill Development Courses (SDCs)…
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Further Branch Training (SDC’s)
Branch Diving Dive UK Wreck Appreciation Wreck Diver Dive Planning & Management Search & Recovery Buoyancy & Trim Drysuit Compressor Operator Diving For All Technical Twinset diver Accelerated Decompression Procedures Closed Circuit Rebreather (CCR) Diver Mixed Gas SPORT (Open Circuit & CCR) Mixed Gas EXPLORER (Open Circuit & CCR) Mixed Gas ADVANCED (Open Circuit & CCR) Gas Blender (Nitrox) Gas Blender (Trimix) Seamanship Boat Handling Diver Coxswain Assessment Chartwork & Position Fixing Outboard Engine & Boat Maintenance Safety & Rescue First Aid for Divers Oxygen Administration Lifesaver Award Advanced Lifesaver Practical Rescue Management Automated External Defibrillator Special Interest Underwater Photography Marine Life Appreciation Ice Diving RNLI Diver Sea-Survival Workshop
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(National Governing Body)
BSAC Diving Grades Military BRd 2806(5) British Sub Aqua Club (National Governing Body) Ocean Diver (4 dives) Sports Diver (10-20 dives) Dive Leader (50+ dives) Advanced Diver (150+ dives) First Class Diver Open Water Instr Advanced Instr National Instr Instructor Foundation Cse Instructor Trainer Branch SADS Expedition SADS
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JSAT Diving Single Service Association RNRM SAA ASADA RAFSA
L4 JSAT Diving Centres Joint Service Sub Aqua Diving Centre Joint Service Adventurous Training Wing (Cyprus)
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JSAT Diving Expedition Centres
Ascension (currently suspended due to runway) Cyprus Gibraltar Plymouth Others (Balmacarra, Porthkerris, Castlemartin) MoD Approved Centres COM-MAC Various civilian dive centres checked annually and approved for Service diving MIL-MAC Military L4 JSAT Diving Centres Branches and Unit Expeditions Military or Civilian Dive Branch individual expeditions BSAC Regional or Mil SAC Associations
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Module OT4 Ocean Diver Dive planning & Nitrox
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Module content The practicalities of dive planning
Decompression planning Dive instruments Differences between tables and computers Altitude and diving Flying and diving Oxygen toxicity limits Gas consumption planning Breathing gas mixes (Nitrox)
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Decompression planning
DCI avoidance Nitrogen management Plan dive depth and duration Use dive tables or computer Using nitrox Less nitrogen means reduced risk of DCI Ocean Divers may use nitrox mixes up to 36% Dive tables Understanding the principles of BSAC tables will help you understand dive computers
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Dive tables – definitions
Depth Deepest depth reached during the dive in metres Descent rate Maximum is 30m/minute Ascent rate Maximum is 15m/minute up to 6m Take one minute from 6m to the surface Ascent check depth At 6m pause to check dive time and depth Dive time From leaving surface, to arriving at 6m 6m Deepest depth Dive time 6m
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Dive tables – tissue codes
CTC SC Current tissue code (CTC) Represents your current nitrogen saturation Starting point for dive planning Surfacing code (SC) Represents your nitrogen saturation at end of dive On the surface after a dive Continued ‘off-gassing’ reduces tissue nitrogen loading Surface interval reduces CTC Gives new CTC for a second dive Tissue Codes : A B C D E F G Nitrogen Load
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Dive tables – single dive planning
Ocean Divers Maximum depth 20 metres No-stop dives for minimum risk – use the white zone Dive up to nitrox 36% , plan on air tables for minimum risk Table A for divers with a CTC of A Example Dive to 9m for 17 min. Surfacing code is B If time or depth between values use next longer time/next deeper depth
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Quiz 1 What is dive time? Time from leaving the surface, to arriving at 6m What is your surfacing code after your first dive of the day to 20m for 30 minutes? E What is your surfacing code after a first dive to 12m for 40 minutes? D
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Dive tables – surface interval
Surface interval table To find your CTC for a second dive Enter at your SC Move across to your surface interval Read new CTC from table Example SC = E Surface interval = 5 hours New CTC = B Use table B for planning
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Dive tables – repeat dive planning
Plan second dive shallower than first Select table that matches your CTC Select depth Read off dive time Example CTC = C = Table C Want to dive to 15m Max dive time is 24 min Surface code will be F
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Dive instruments To dive the plan made using tables you need
Depth gauge Watch Dive slate Gas analyser (nitrox mixes) Plan the dive and dive the plan
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Dive computers Computer functions Calculate nitrogen loading
Provide planning information (depth and time) Allow personal risk settings Record depth, time and temperature Give audible and screen warnings Log previous dives
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Dive computers – dive planning
Single dive planning Read instruction manual Switch on and select planning mode Set planned depth and look up no-stop time ‘Little longer’ or ‘little deeper’ Use a slate to record the plan Repeat dive planning Computer knows surface interval Repeat as single dive planning Computers are linked to a single diver Plan the dive and dive the plan PRESS PRESS PRESS PRESS
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Tables versus computers
Different dive profiles Dive tables: ‘square’ profile based on maximum depth Dive computers: variable or multi-level profile Dive computers: more data in real time
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Dive plans Whether using tables or computers Do the deepest dive first
Never push the limits of tables or computers Start deep and progress to the shallows BSAC tables allow for 3 dives in 24 hours Computers may have similar limits Buddies may have different profiles Adhere to the most conservative profile
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Limitations of tables and computers
Both minimise risk of DCI but not infallible DCI risk factors Cold Alcohol/drugs Poor buoyancy control ‘Saw-tooth’ profiles Individual susceptibility Fitness Exertion Dehydration Pre-dispositions
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Altitude and diving Table levels Level 1 tables for sea level
Levels 2, 3 and 4 for altitude Require additional training When to use other levels Travelling - hills and mountains Living or diving at altitude Inland sites in bad weather Flying Computers and altitude Read instruction manual
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Flying and diving Flying before diving Tissues off-gas
Stresses of flying Recover before diving - 10 hours minimum Flying after diving Increased level of off-gassing – DCI Ensure long surface interval between last dive and flying Tables require CTC of A or B Computers – follow instructions
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Oxygen toxicity Nitrox
Reduces DCI risk but increases oxygen toxicity risk Ocean Diver should not exceed 20m Dive computer settings Set to air to reduce DCI risk Using nitrox setting increases dive time and increases DCI risk
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Gas consumption planning
Gas planning Ensure sufficient gas for the dive Ensure good reserve Rule of thirds Use one-third out Use one-third return Keep one-third in reserve
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Rule of thirds Example: Cylinder start pressure
210 bar Cylinder pressure at turn around / half way point 140 bar Cylinder pressure at surface 70 bar as reserve Always aim to surface with 1/3 of your gas in reserve 50 bar should an absolute minimum reserve
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Gas monitoring Regularly monitor your contents gauge – it is your lifeline Running low or out of gas should not arise under normal diving conditions Gas consumption increases when Physical effort increases Divers are cold or anxious Shorten or terminate the dive
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Quiz 2 How deep can an Ocean Diver go on 32% nitrox? 20m
How much gas should be held in reserve? 1/3 but not less than 50 bar What are the risk factors for DCI? Poor buoyancy control Cold Dehydration Alcohol/drug consumption
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Using nitrox What is nitrox? A breathing gas with >22% oxygen
Nitrox mix defined by the Oxygen content Nitrox 32 – 32% oxygen + 68% nitrogen Nitrox 36 – 36% oxygen + 64% nitrogen
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Nitrox benefits Advantages of less nitrogen
Reduced risk of DCI when used with air table or computer Some divers find it reduces fatigue Disadvantages Nitrox divers can still suffer DCI Some methods of cylinder filling can expose cylinders to 100% oxygen Cylinders need periodic cleaning Oxygen toxicity
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Oxygen toxicity Risk increases with Depth Dive duration
Percentage of oxygen Avoidance Observe maximum operating depth (MOD) Signs and symptoms Sight or hearing disturbance Muscular twitching Convulsions Unconsciousness Treatment Abort the dive and return to surface Depth MOD Dive duration
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Avoiding oxygen toxicity
Guidance for Ocean Divers Only allowed to dive to a maximum depth of 20 metres Participate only in no-stop dives using air or nitrox up to 36% Adherence to these guidelines make oxygen toxicity very unlikely Plan dives using an air table or air computer
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Nitrox analysers Nitrox must be checked with an oxygen analyser before use Mix should not vary more than ±1% from the desired mix All cylinders should be clearly marked with oxygen percentage and MOD MOD = maximum safe depth for the nitrox mix Follow analyser manufacturer’s guidance
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Analysing a nitrox mix Ideally check the mix yourself
1. Switch on Analysing a nitrox mix 2. Calibrate Ideally check the mix yourself Calibrate the analyser Keep flow rate even and low Avoid windy conditions Avoid moisture Store analyser away from elevated oxygen levels If using a filling station Ask the technician to analyse the gas in your presence Filling stations may require a signature to confirm the percentage supplied Present your nitrox qualification when ordering a mix 4. Analyse 3. Open cylinder 5. Take reading
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Quiz 2 What are the signs and symptoms of oxygen toxicity?
Sight or hearing disturbances Muscular twitching Convulsions Unconsciousness What are the advantages of nitrox? Reduced risk of DCI when used with air table or computer
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Rebreather Divers Rebreathers What are Rebreathers
Buddy considerations when diving with Rebreather divers
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What is a Rebreather A continuous breathing loop
Mouthpiece Divers lungs and mouthpiece Counter-lungs Breathing bags (counter-lungs) Recycles gas through ‘ loop’ using one way valves to maintain gas flow Gas Cylinder Carbon dioxide (CO2) removal - absorbent or ‘scrubber’ canister Requires small gas supply connected into loop to replenish oxygen consumed by respiration Absorbent canister (the scrubber) Delivers nitrox mixes
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Types of Rebreather Semi-closed Circuit Rebreather (SCR)
Cylinder of pre-selected gas mix Maximum operating depth (MOD) determined by mix being used Excess gas vented off periodically, bubbles Closed Circuit Rebreather (CCR) 2 cylinders, oxygen and air Electronically controlled - optimum Nitrox mix to depth No bubbles, except for venting on ascent Both systems should have an adequate bailout system that can be used as an AS
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Diving with Rebreathers
Diving on Rebreathers requires additional training and practice Advantages Extends dive duration by the gas recycling process Extends no-stop dive times appropriate to gas mixed being breathed No or hardly any bubbles - get much closer to marine life Disadvantages Rigorous monitoring Rigorous maintenance and preparation
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Diving with Rebreather Divers
If a Sport Diver buddies a Rebreather diver Dive is planned to The most conservative decompression schedule of the gases being used The most conservative operating MOD determined by either of the gases used Must be experienced in the type of diving conditions for the dive Must be able to recognise underwater problems pertinent to Rebreather diver Must be able to perform CBL and surface support on Rebreather diver Rebreather Try Dive, Practice
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Questions ?
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Summary BSAC as an Organisation BSAC Diver progression JSAT Diving
Module OT4 Summary BSAC as an Organisation BSAC Diver progression JSAT Diving Decompression planning Oxygen toxicity limits Gas consumption planning Breathing gas mixes Diving with Rebreathers
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