Running hot and cold
Divernet
Divers find themselves either too cold or too hot in winter. Why too hot Because many use this time to jump on a plane and get in some warmwater diving. They might well be the same divers who troop down to a chilly freshwater inland site to get some practice in before they go. You wouldnt wear a shortie for an ice-dive or a drysuit in a tropical heatwave, but if youre going to extremes this winter, make sure you know the drill...

COOL-HEADED
Dont embark on a long drive to go diving without a good nights sleep and a proper breakfast. Give your body its best shot at coping with the cold. Inland sites look innocuous enough with their absence of tides or currents, but every year divers have avoidable accidents in them - sometimes fatally.

  • Wear appropriate thermal undergarments, a hood and gloves to keep warm during the dive, but be sure that you can operate all your equipment properly before you go in. Cutting the tip off the finger and thumb of a neoprene glove will help you to keep your dexterity without losing any comfort.

    Be familiar with the inflation and air-dumping procedures with your drysuit before you find yourself in deep water. Make sure the inflation valve is not obscured by other kit and that the dump valve cannot get blocked by your undersuit.

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  • Take precautions to avoid your regulator freezing and going into free-flow. That means choosing a unit that is designed for coldwater conditions, with an environmentally or dry-sealed first stage and a good heatsink of metal designed into the second stage. The surrounding water, however cold, will warm the cold air that has suffered a huge drop in temperature , along with the drop in pressure on leaving the cylinder. Be sure that your cylinder is filled with properly dried air and avoid taking breaths from your regulator before immersion, as this will fill it with moist exhalations.

    Even if your regulator does free-flow, this should be no more than an inconvenience. Know how to breathe from a free-flowing regulator. You do this by holding the mouthpiece against the top of the mouth and angling it away from the bottom so that the excess air can escape. Practise this regularly by pressing the purge button in the training-pool. A regulator is most likely to freeze when the tank pressure is high, so if you do have a problem, you should still have time to make it to the surface.

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  • Avoid high demands for air during the dive by limiting your depth and work-rate. If your regulator should freeze, it is quite likely that your buddys is about to do the same. Increasing the demand on his by using his octopus will probably just double your problems.

    Once you are out of the water, have a change of dry clothes in which to travel home; your drysuit might not be as effective as you would like. Youll appreciate a warm drink from a vacuum flask, too.


    HOT AND UNBOTHERED
    Remember that everywhere north of the tropics has its own winter season. The weather there might be more amenable than in the UK, but copious amounts of blue ink used in the colour brochures might not reflect the weather at your chosen destination in March, for instance. Many northern Red Sea dive-guides use drysuits at this time of year, but this doesnt stop British sales assistants selling lightweight shortie wetsuits to those about to visit Egypt in spring. Wherever you go, however hot, the water is bound to be cooler than you are. Choose an adequate suit by asking others who have been before you at that time of year. If the climate is hot, it is almost as important that your suit allows you to get in and out of it without a fight so you dont overheat.

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  • International travel is so convenient now that its easy to forget that many tropical destinations suffer from serious endemic diseases. Amoebic dysentery and malaria are serious health risks in some areas, and you should take advice from your doctor or travel clinic on how to protect yourself. Whether to drink the water and which, if any, anti-malaria pills to take over what period, is as important as making sure all your vaccinations are up-to-date.

    Once you are on the plane, avoid consuming alcohol, even if everyone around you seems to be at it. Reduced cabin pressures make you drunk more readily and the air-conditioning will dehydrate you more easily, too. Drink loads of water and congratulate yourself on still feeling good when the time comes to disembark and deal with the trials and tribulations of immigration procedures.

  • Once youve got to where you are going, dont cook yourself in that welcome sunshine. People are much more aware now of the damage solar rays can cause. Wear a hat and keep covered, or stay in the shade. When you do expose your skin, give it a good coating of a water-repellent sunscreen first. Keep well hydrated by drinking more (bottled) water than you really relish. If you want to drink alcohol, wait until the sun has gone down.

    hspace=10 Good sunglasses are important. Choose ones with optically correct lenses which will not distort your vision. Thanks to modern CE marking, it is easy to avoid those products which do not filter out the harmful wavelengths of ultraviolet light.

  • Protect your skin from more than just the sun. Use an effective insect repellent and cover up during the evenings if you are land-based. There are fewer problems with mosquitoes at sea. Your epidermis is the first barrier against infection. If you puncture it, even with the most innocent small abrasion, wash the wound well in clean, fresh water and apply antiseptic cream. Marine organisms can enter the body through such injuries and cause serious havoc later - which is another reason to wear a full wetsuit of some sort.

    Warmwater destinations often give you the opportunity to dive more often than you would at home - up to six times each day. Remember that even though you might have had a few hours sleep in between dives, you will have embarked on a series. Be sensible and leave at least a couple of hours between each dive, do longer stops in the shallows than your computer might ask and dont go as deep as you might normally during a single-dive day.

  • Finally, be sure that you have adequate insurance before you set off - a policy that will get you home in a worst-case scenario. Cover all the eventualities and youre set for a great time.

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