If you learned to dive in warm, tropical waters, as many of us did, the thought of going for a dive in 40 to 50 F (5 to 10 C) waters may not be very appealing. But with proper preparation and a little extra training, you can have just as much fun on colder dives — and feed your scuba addiction year-round. Here are a few things to think about if you’d like to try out cold-water scuba diving.
Drysuit or wetsuit?
Everyone has different comfort levels with regard to feeling the cold underwater. You might be happy in a 7 mm wetsuit in 61 F (16 C) water, while your buddy won’t even entertain the thought of jumping into water colder than 68 F (20 C), without a drysuit. In order to adequately protect yourself from hypothermia in water temperatures below 50 F (10 C), a drysuit is really the only sensible option. There are many different types available that will affect warmth, buoyancy, freedom of movement and durability. Serious cold-water divers should buy a made-to-order drysuit. Talk to members of your local dive club or dive shop to help you decide what type of drysuit would be best for the environment you’ll be diving in. Once purchased you’ll need to enroll in a specialty course to learn how to use it safely.
Get used to the cold
The first few moments after jumping into cold water can feel like a big shock on your face and hands. You may also feel like you can’t breathe properly. Don’t worry — this is the body’s normal response, and it’s called the mammalian diving reflex. Allow yourself time to acclimatize on the surface and it will pass. Within a minute or two you’ll relax and become ready to start your dive.
Use a regulator designed for cold water
As your regulator provides you with air during a dive, the air expands as the pressure is reduced from the tank to the first stage, and then again as it reaches the second stage. As the air expands it cools, and if it cools too much it can “freeze,” which can cause a free-flow. There are a few things you can do to minimize this risk when cold-water scuba diving. First, make sure your regulator is environmentally sealed and designed for cold water. Try not to add air to your BC or drysuit while breathing in; try not to use the purge button; and don’t breathe from the regulator while out of the water at the surface. Moreover, get it serviced regularly by a qualified, brand-specific equipment technician.
Be prepared to carry more weight
Thicker wetsuits will increase your buoyancy, which means you’ll likely need to add more weight when cold-water scuba diving. Drysuits are also made of buoyant materials, and will require you to inject air into them to counter the increased pressure of the water as it squeezes the suit against your body. Steel tanks are heavy and will help offset the additional weight you’ll need. If you’re using a wing-style BCD, you can also use a steel back-plate. In any case, be prepared to carry more weight than you do in warm water.
Cover your hands and head
Donning a neoprene hood will help to prevent heat loss from the head. It will need to be snug to minimize water circulation, but not so tight it’s unbearable to wear. Depending on your drysuit’s wrist seals, you may be able to use dry gloves. A cheaper and easier option is to use wet neoprene. Again, the gloves will need to be thick enough to keep you warm, but not so thick that you lose all dexterity.
There are lots of other tips and tricks to cold-water scuba diving that you can pick up along the way. Start with shallow, simple dives, and with someone who’s got experience in the environment. If you’re adequately prepared, you won’t feel cold during the dive. But we do suggest swapping that post-dive beer with some warm soup and hot tea.