ST3

BSAC Sports Diver Training: 

Equipment & Techniques BSAC Sports Diver Training

Equipment & Techniques: 

Equipment & Techniques Aims Shot Lines Surface Marker Buoys Other surface detection aids Distance Lines Compass Dive Torches

Shot Lines: 

Shot Lines What is a Shot Line? Surface and underwater datum point Why use a Shot Line? Shortest route to/from surface More comfortable and secure Used when making deco stops Marked entry and exit point - safer dive marshalling/boat cover

Shot Lines - Decompression: 

Shot Lines - Decompression Back-up Deco Cylinder Decompression Trapeze All require return to shot line Extra line attached to main shot line Buoy supports spare cylinder Can be disconnected to drift with current - needs diver ‘logging’ system Lazy Shot Line With solid bars

Surface Marker Buoys: 

Surface Marker Buoys Two Types SMB Permanent indication of divers position Delayed SMB (DSMB) Deployed from underwater by divers to indicate ascent location Methods of deployment Use and Precautions

The SMB: 

The SMB Highly visible surface float Generally inflatable Supports 10-20 kg Quick release attachment to diver Line How much line? - 1.25 x dive depth - strong and thin Reel Provides safe stowage of line Lock off mechanism

SMB - Deployment: 

SMB - Deployment Entry Carried or passed to diver after entry Descent Reel out to rate of descent Hold reel away from body/kit Buddy positioning During dive Keep line taut but ‘comfortable’ Adjust for depth/lock off Ascent Reel in and control buoyancy

When to use a SMB: 

When to use a SMB When position of divers needs to be known at all times Drift dives When divers may travel some way from entry point If local regulations require use If surface traffic anticipated SMBs are not suitable if high risk of line snagging Wrecks Gullies below kelp, coral

SMB - Precautions: 

SMB - Precautions Avoid entanglement Careful & controlled deployment Both divers’ positioning Aware of line at all times Ensure reel can be quickly released if necessary If possibility of separation - use SMB line as ‘buddy line’ On drift dive Reduced visibility

Delayed SMB (DSMB): 

Delayed SMB (DSMB) For deployment A connecting line and reel A marker buoy which can be inflated underwater Sent to the surface to mark position of divers at end of dive Usually sausage shaped for visibility from long range About 1m long with 20-25 kg buoyancy

When to use a DSMB: 

When to use a DSMB High risk of SMB line snagging during dive Well-defined sites marked by shot lines Ascents from sheltered sites into a current When not to use a DSMB When knowledge of the divers position at all times is essential In areas of significant surface traffic Use when a conventional SMB is inappropriate

Types of DSMB - 1: 

Types of DSMB - 1 Open-ended DSMB Advantages Simple construction Compact Disadvantages Manual inflation Do not hold air well at surface Self-sealing DSMB

Types of DSMB - 2: 

Types of DSMB - 2 Self-inflating DSMB Advantages Simplest to deploy Fully inflated on reaching the surface Disadvantages Least compact Most expensive

Methods of Deployment: 

Methods of Deployment Secured deployment Free deployment

DSMB - Use & Precautions: 

DSMB - Use & Precautions Before diving with any DSMB Ensure reel is neatly coiled Stow neatly to avoid snagging Ensure that it is not fastened to you ! Self-inflating DSMB by far the easiest Open-ended/self-sealing DSMB Use AAS Simpler if one diver holds reel while other inflates DSMB Initial small inflation to straighten DSMB Deploying the DSMB

DSMB - Use & Precautions - 2: 

DSMB - Use & Precautions - 2 Practice - Practice - Practice ! Buoyancy control Do not over inflate If mid-water, inflate below deepest stop Keep hands clear of spinning reel Check DSMB has reached surface On ascent keep line under tension In case of diver separation Each diver must carry a DSMB Each diver must be able to deploy it unassisted

Additional Surface Aids: 

Additional Surface Aids Flares Whistles Mirrors

Distance Lines: 

Distance Lines What is a distance line? Temporary bottom line that ensures return to fixed datum point Use when Guaranteed return to shot line is essential Visibility is poor The site is reasonably compact Can also be used as guideline for other divers

Types of Distance Line: 

Types of Distance Line Advantage All divers have one Disadvantage Reel and line may be buoyant A dedicated distance line? Advantage Weighted (sinks) Reduces chance of entanglement Disadvantage Heavier An SMB line and reel?

Distance Lines - Use: 

Distance Lines - Use Non-sliding attachment to shot line Line secured at changes of direction SMB line? Maintain reasonable tension

Lines and Safety: 

Lines and Safety Precautions Sharp knife, net cutter, scissors Always keep line taut Deploy at arms length Avoid swimming close to line Avoid entanglement with other lines Do not use same reel for both distance and DSMB lines If air/dive time is short - cut line and ascend using a delayed SMB + second reel

The Diving Compass: 

The Diving Compass Use to:- Navigate to and from specific area

Compass Bearings: 

Compass Bearings Compass aligned to point of interest along direction of travel arrow. Bearing set using rotating bezel + cursors to north seeking needle Underwater - journey out Needle kept within cursor, diver aligns body with direction of travel arrow Setting the direction Bearing taken on surface towards site Time or count fin strokes Reciprocal bearing - journey back Reverse/reciprocal bearing (180o difference) Time or fin strokes back to start point

Compass - Use & Precautions: 

Compass - Use & Precautions Use Compass held level, direction of travel arrow to centre line of diver’s body Current - keep bearing but angle finning Sources of error Magnetic influences Wrecks Any other ferrous metal Disbelief! Precaution Fixation!

Diving Torches: 

Diving Torches Illuminates dive area Colours, points of interest Essential for night dives Many types of torch Pressure rated Robust Battery or rechargeable Torch care Bulbs, O’ ring seals ! Wash after every dive Torches & safety Lights the diver’s position

Summary: 

Summary Equipment & Techniques Shot Lines SMBs and DSMBs Other surface detection aids Distance Lines Compass Dive Torches Ensure all equipment Kept in good working order Washed/checked after each dive PRACTICE - PRACTICE - PRACTICE