Equipment Configuration Twinset
Backplate and harness
A stainless steel backplate is recommended. A backplate made of aluminium can be used if it gives the student better balance in the water.
Harness should be made of approximately 50 mm wide webbing and contain no quick releases.
One D-ring should be placed on each side of the chest straps at collar bone level. One D-ring should be placed on the left side of the waist-strap, approximately in the middle of the body near the hipbone.
Crotch-strap should have two D-rings on it – one scooter D-ring on the forward side of the body and one D-ring mounted approximately 20 cm under the backplate.
Wing should have approximately 20 kg lift and a dump valve mounted on the left forward side.
For single cylinder a special wing made for this is used.
Manifold doubles with isolator valve
Should have a capacity of at least 4800 litres of gas. Valve knobs should be made of rubber.
Doubles should be mounted together with stainless steel bands and should not have tank feet.
Scuba Diver, Extended Basic Skills and Wreck Diver can be done with single cylinder configuration.
Primary 1st stage
Primary 1st stage should be mounted on the right valve from the point of view of the diver wearing the doubles. Primary 2nd stage should be connected to the primary 1st stage with a 210 cm long low-pressure hose. On the hose, close to the 2nd stage, there should be a bolt snap tied on with a piece of polyester/nylon line.
On the primary 1st stage there should also be a low-pressure hose for the wing which is a primary means for buoyancy and buoyancy control.
Secondary 2nd stage
Secondary 1st stage should be mounted on the left valve from the point of view of the diver wearing the doubles. Secondary 2nd stage should be connected to the primary 1st stage with a 55-60 cm long low-pressure hose.
On the secondary 2nd stage there should be a bungee cord mounted with the help of the same zip-tie that holds the mouthpiece in place. The bungee cord functions as necklace for the 2nd stage.
On the secondary 1st stage there should also be a submersible pressure gauge mounted on a 55-60 cm long high-pressure hose. There should be a bolt snap tied to the hose with a piece of polyester/nylon line close to the submersible pressure gauge.
Cylinders for decompression and bottom gas
These tanks should be made of aluminium and rigged with bolt snaps. The volume of the tanks should be 11 litres for bottom gas and minimum 5.5 litres for decompression gas. The tanks should be marked with the maximum operating depth of the gas they contain. Marking should be made with black digits on white background and the digits should be at least 70mm high. Markings should be placed on each side of the tank at 3 and 9 o’clock when the valve is pointed at the diver, right beneath the top curved part of the tank.
Regulators for tanks containing decompression and bottom gas
Should have one second stage mounted on a 90-100 cm long low-pressure hose and one submersible pressure gauge mounted on a 10-15 cm long high-pressure hose. The submersible pressure gauge should be tied on the 1st stage with a piece of nylon line.
Suit and thermals
Suit and thermals should be chosen appropriately to the temperature of the water dive will be conducted in. The suit should have a pocket on each side of the upper leg. Drysuit should not be made of compressible material. When diving with drysuit and helium-based breathing mixtures, a separate drysuit inflation tank should be used. It should be equipped with a 1st stage with over-pressure valve and a low-pressure hose of appropriate length. The tank should be mounted on the backplate.
The primary light should have a focused or focusable beam in order for light communication to be effective. The light head should have a loop at the back made from bungee cord or polyester/nylon line by which it should be able to be attached to a D-ring without blinding anyone. If the primary light has a separate battery canister it should be placed on the right side of the waist strap and secured with a buckle.
Depth and time instruments
The primary instrument should be mounted on the right arm. Secondary instrument should be placed in the right pocket and secured with a double-ender clip. A bottom timer is recommended, but a computer can be used if it has gauge-mode.
If the dive requires a compass, it should be mounted on the left arm.
Line spools and reels
Spools should be placed in the left pocket and secured with double-ender clips.
Line reels with side-handle are recommended. A reel should be placed either on the left hip D-ring or on the d-ring on the back of the crotch strap.
Surface marker buoys
Surfer marker buoy should be red or yellow and stored in the left pocket, secured with a double-ender clip. Two surface marker buoys should be used if a dive contains drifting decompression – colours differ for “OK” and “emergency”, make sure to understand the local practise.
A cutting tool (a small knife is recommended) is placed on the left side of the waist strap.
Backup lights should be secured with bolt snaps to the chest D-rings and to the webbing with rubber bands.
Mask and fins
The masks should have low inner volume, give broad view and be equipped with a strong mask strap. Backup mask should be placed in the right pocket and secured with a double-ender clip. Robust fins with heel straps made of rubber are recommended.
Fin blade should not be divided along its length (so called split fins).
Should be placed in the right pocket and secured with a double ender clip.