Gearing Up for Cold Water Diving

Thermal Protection

While most divers are putting their scuba equipment into winter storage, others are gearing up for a season of cold water diving. It's a great way for you to remain active in the sport throughout the year. But, in order to remain a contented and safe diver, you need to know about thermal protection.

How the Cold Affects You

Being exposed to cold conditions has an effect on your blood's circulation. Usually, blood flow to your skin and appendages is diminished in favor of keeping your vital organs warm. The reduction in circulation happens gradually over the course of a dive or multiple dives. Because of the impaired blood flow to your body's appendages, finger dexterity is reduced. This can lessen your ability to perform certain skills such as mask clearing, and the capabilities to adjust straps and belts or operate snaps and clips. Moreover, it is thought that the body tissues of the skin and extremities will have a reduced off-gassing due to the decreased blood flow. Thus, you will have a higher risk of decompression illness (DCI).

Also, when your body is cold during a dive, your rate of breathing increases, which means your rate of air consumption increases, too. As a matter of fact, it will almost double. You'll end up using more air from your tanks in less time than if you were doing the same dive under warmer conditions. Furthermore, you'll have to end your dive with more reserve air in your tank. For example: if you normally end a dive with 200 psi of air, you'll need to end with 400 psi. 200 psi might not be enough if you're cold and your air use has increased.

The effects of being cold and minor problems could climax into a real emergency.

How A Wetsuit Works

A wetsuit is the most common item of exposure protection. The purpose of a wetsuit is to insulate your body and minimize heat loss. Wetsuits operate by trapping a layer of water between your skin and the suit. The heat from your body warms up the layer of water, which helps you retain your body's temperature. The thickness and quality of the wetsuit material (usually neoprene) determine the suit's ability to insulate. The thicker the neoprene, the warmer you'll stay. Also, your wetsuit will decrease heat loss by minimizing the water's movement across your skin. This is why the wetsuit's cut, fit, stretch, seals, and fasteners are important.

A dry suit is the next most common item of exposure protection. It works in much the same way as a wetsuit, except that it keeps you dry. A dry suit insulates your body by trapping air between your skin and the suit, instead of water.

As you descend in the water, your wetsuit compresses because of the water's pressure. This compression of the wetsuit reduces your buoyancy and thermal protection. The biggest reduction in your wetsuit's bulk and insulating protection occurs in the first thirty-three feet of water. There is no way to make up for the lost insulation once you're in the water. Compensate before the dive by putting on extra layers of thermal protection to meet the demands of your diving conditions.

Choosing the proper exposure suit is an important part of planning your dive, whether or not you use a wetsuit or dry suit. By logging water temperatures, depths, bottom times, and thermal protection information, you'll put together a statistical reference work for future dive planning.

Five Strategies For Preserving Body Heat:

For a more comfortable and ultimately safer dive follow these tips for conserving body heat.

Stay warm before the dive. Heat loss is gradual and can start long before you get to the dive site.
Stay warm between repetitive dives. Standing around in wet gear between dives can add to your body's deprivation of warmth through evaporative heat loss.
Get warmed up as soon as possible after a dive. You can start on the dive boat by toweling off and getting into dry clothes.
You can develop hypothermia without immediately recognizing it. When choosing your exposure suit, err on the side of thermal protection.
Become an educated consumer. Visit your local dive shop and have them show you the different styles of protective garments and accessories. Don't be afraid to ask questions.

From About.com