Cold Water Diving



Cold Water Diving

Several recommendations regarding safe Cold Water Diving during winter.

  1. Don’t leave the regulators in the car overnight. Ideally, don’t leave cylinders in the cold overnight either.
  2. Keep regulators dry prior to use. (Use good air – dry).
  3. When testing kit before entering the water, don’t exhale through the regulators. (The condensation promotes freezing.)
  4. Once you start breathing from a regulator, don’t remove it from your mouth. (See condensation.)
  5. Breath normally and steadily when in the water
  6. Add gas for buoyancy in small controlled bursts.
  7. Don’t use the second stage for DSMB inflation – if you do, use short bursts of the purge valve (not long bursts).
  8. Make sure your regulators are in good operational condition. Properly serviced, no leaks of slow dribbling of gas from the second stage.

Sound Advice

Just because you can withstand air temperatures of 10C and lower it does not mean you will be OK Cold Water Diving. The body is subject to greater heat loss in water than air. Make sure you have suitable protection.

Most regulators will cope with cold water. A proper cold-water regulator is better, with an environmental kit. Some travel regulators are only designed for warm water diving 5C or above. Most Apeks Regulators are Cold Water Diving suitable

It is the drop-in gas pressure that causes the icing. Increasing the gas pressure heats the gas temperature, reducing the pressure decreases the gas temperature. 

The ‘heat’ from the surrounding water is used to ‘warm’ the first stage and second stage to avoid freezing. This is less efficient in cold water!

High volumes of gas passing through the first stage increases the icing risk. Holding the inflate button or purge button down, or an increase in breathing rate, increases the gas flow through the first stage increasing the risk of icing.

Two people breathing off the same first stage (AAS), is bad news, because the gas flow is twice as high as normal. In fact, the flow is even higher, because both individuals are stressed. 

Other sensible plans are to dive conservatively, not too deep, in case a direct ascent to the surface is required. Consider avoiding dives requiring compulsory Decompression Stops.

The risk of DCI is higher in divers suffering from cold at the end of the dive. Especially if the diver was warm at the start.

Circulation efficiency changes with temperature. When warm, the blood circulates efficiently, including the extremities. Thus, when at depth, Nitrogen is carried efficiently through the body, efficient ‘on-gassing’.

When cold, circulation is poor as the blood flow is restricted to the core of the body. Thus ‘off-gassing’ is poor.

More Tips

Either, reduce the dive time giving a ‘no-stop’ buffer. Or, increase the stop time beyond that recommended.

  1. Keep warm between and prior to diving.
  2. Being properly ‘fuelled’, is a good start. Slow energy releasing food stuffs such as oats (porridge) is a good starting point.
  3. Where layers that trap heat. Remember to adjust your weighting to account from extra layers of clothing.
  4. Take wet drysuits off between dives. Evaporation will result in cooling.
  5. Use wind proofs to protect from the wind
  6. The highest volume of heat is lost from the head. Use a hat between dives, and a good hood during your dive. (Make sure you can still mask clear and seal your mask with a new hood).
  7. Cold fingers make simple tasks difficult. Keep your hands warm. Thicker gloves impede dexterity, (as do cold fingers,) make sure you can operate equipment with the thicker gloves you are using. Consider dry gloves.
  8. Being cold, adversely effects both enjoyment and competence. finish the dive early if you are getting cold or chilled.

Cold Water Diving can also be very rewarding. The water is generally clearer providing excellent visibility. Here are 8 Cold Water Destinations

Plan for the occation and ensure you have the right equipment with you, this includes warm gloves, hat, coat, dry socks, dry underclothes.

If you need one take two never really disappoints when is a jam.

A flask containing a hot drink, soup or… Never goes amiss after a cold dive.

Cold Water Diving is a challenge. Another to master and increase your experiences. Dive safe. Ask for help if you require assistance.

Under normal circumstances we meet on Sunday nights at One Leisure St Ives (the St. Ives Recreation Centre), with theory lessons starting at 6:30PM and the pool is available exclusively for our training from 8:15PM. One Leisure St Ives Recreation Centre Westwood Road, St. Ives Cambs. PE27 6WU.  

Due to Covid 19 we have suspended all Pool training and Try Dive activities.

St Ives Sub Aqua Club is affiliated with BSAC (British Sub Aqua Club)

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