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1. Cold Water Diving Requires Additional Weight:
Divers use thicker, more buoyant wetsuits (or drysuits) in cold water, which requires the use of more weight. This is obvious, and most cold water dive centers will assist divers in selecting the appropriate amount of weight for thick exposure protection.
However, there is an additional aspect of cold water diving that a diver should consider before deciding on the amount of weight to carry on his first few cold water dives. Until a diver gains experience in cold water, the initial surprise of cold water on his face may make normal breath control difficult. In my case, I was not able to exhale fully at the surface to begin my descent as I normally would, and I has to grab an extra few pounds from the captain to descend. An experienced cold water diver my size would need eighteen pounds of weight. I needed twenty pounds on my first few dives because I couldn't get the air completely out of my lungs.
2. Gearing Up for Cold Water Diving:
Plan ahead. Once a diver is wearing his gloves, it becomes very difficult to make small adjustments such as tucking mask skirt under the hood. On my first dive, I looked like a bit of an idiot when I put on all my gear but my mask, hobbled over to the entry platform, and then had to ask the divemaster to tuck my mask skirt into my hood because I waited to put my mask on until the last moment and couldn't get the skirt under the hood with my gloves on. This sort of humiliation would have been avoidable if I had simply planned ahead.
3. Be Prepared for the Initial Cold Water Shock:
Divers transitioning to cold water diver should be prepared for the short initial, shock of entering cold water. For the first few moments in the cold water, a diver may feel that he cannot breathe easily. This is a physiological reaction known as the Mammalian Diving Reflex, and it is perfectly normal when a person's head is submerged in cold water. It will pass. I managed my reaction to the cold by floating on the surface with my face in the water until I could control my breathing and felt comfortable. After about twenty seconds I felt great, and was ready to start my dive.
4. If a Diver Feels Cold, His Air Consumption Rate Will Increase:
When a diver's body becomes cold, he will burn more calories to keep warm. He will use more oxygen and his breathing rate will increase. If the diver becomes very cold, he will shiver and his air consumption will increase more from the extra work of shivering. Thicker wetsuits and drysuits, as well as the extra weight necessary to compensate for this thicker exposure protection, will increase a diver's drag, and thus his air consumption rate. I used a thick wetsuit for my dives, a noticed an increase in my air consumption rate as I became chilled near the end of the dives. What is the solution to this problem? Wear proper exposure protection. I would have done better to use a drysuit or to end the dive once I became chilled.
5. Use Regulators Appropriate for Cold Water:
Most dive shops servicing cold water diving destinations rent or sell regulators appropriate for cold water diving. It is vital to use a regulator approved for cold water diving, as the first stage of a a non-cold water regulator may “freeze” due to normal cooling from gas expansion combined with chilly water, causing a free flow. Divers should also be sure to review standard protocols to avoid causing a regulator free flow, even when diving with cold water regulators. The divemaster on our boat recommend that the divers avoid purging the regulator or inflating the BCD while inhaling. These actions cause increased demand on the regulator first stage and may trigger a free flow. Also review the procedure for handling a regulator free flow.
6. Mask Clearing in Cold Water – Be Prepared:
Most divers find that the shock of cold water on the face makes exhaling to clear a mask difficult in cold water. This reaction can be overcome with practice, but divers must experience the cold water shock a few times before they learn clear their masks easily. It's not fun, but practicing mask clearing in cold water is essential to being safe on cold water dives. The first time I cleared my mask in cold water, I was taking a drysuit certification course and the instructor had all the students practice clearing their masks in about 3 feet of very cold water. We all thought this was ridiculous given our level of experience until we tried it. About half the class panicked and stood up. After two or three attempts, however, we became accustomed to sensation of cold water on out faces, and could clear our masks easily.
I work and dive in warm water. When the subject of cold water diving comes up, my clients frequently shudder and claim, “you will never get me in into that cold water!” This is silly! With proper preparation and gear, a diver shouldn't be cold – even in cold water. When it is done correctly, cold water diving should be just as comfortable as warm water diving, and equally as enjoyable.
Thanks to Natalie Gibb About.com
Kathy Dowsett
www.kirkscubagear.com
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