Now that we’re fully into winter, it seems as though that the die hards are the only ones willing to go into the water, no matter how cold they become. For many freedivers, the prospect of jumping into 55 degree water (or less in many areas) is about as pleasant as going to the dentist.
The cold rush of water down many a wetsuit, or the proverbial "icecream headache" is enough to make most divers jump right back out.
There are several ways to tolerate, and in many instances enjoy, the coldest part of the year for many of us.
How do we get cold in the first place.
Traditionally, a vast majority of exposure suits range in thickness from 5mm to 7.5mm. Freediving in a traditional wetsuit tends to be the biggest offender in the area of cold water rushing into a divers suit and causing the immediate chill that comes with the water. Most divers assume that by going to a thicker wetsuit, that this will eliminate there being cold.
This is not necessarily the case.
While adding more neoprene will help some, the tradeoff is the added buoyancy created by the extra neoprene, as well as the reduced freedom due to the excess neoprene. Who wants to wear more lead weight to dive?
We as freedivers participate in this sport to feel the freedom we have not being encumbered by excess lead weight and other gear.
Let’s take a look at the design of a typical wetsuit.
These suits have a farmer john and zippered jacket without an attatched hood.
The zipper allows water to seep in quickly, and also allows water to exchange freely, thus never allowing the diver’s body heat to warm the water in the suit to keep him (her) warm. As a result, the diver becomes chilled in a short period of time. Next, since there is no hood attatched to the top, water also seeps in throught the neck opening, allowing still more water to exchange back and forth. Another common feature of many wetsuits is the plush lining inside to make them easier to put on and take off. The downside of the ease of donning and doffing is that it also allows a small amount of water to exchange in and out of the suit, due to the small amount of air space between the divers body and the actual inside skin of the suit. All of these factors contribute to a less than ideal day of diving in cold water.
Suits designed for freediving take a different approach to their philosophy in design and construction.
The first thing you notice is that the hood is attatched to the removeable top. This eliminates one opening for water to enter the suit, thus keeping the water that has entered the suit to stay there and keep the diver warm. Next if you look at the top itself, most, if not all of these tops have no zippers. They are designed to be pulled on like a sweatshirt. This eliminates the second offender for water exchange, the zipper. Lastly, freediving suits eliminate plush linings. Instead they are typically smooth skin-in neoprene, making for a suit that is somewhat difficult to put on and take off. But this skin-in neoprenes adhesion to a divers skin as they are trying to put it on is the primary reason why they are warmer than in a traditional wetsuit. The smooth skin of the neoprene adheres to the divers skin without any gaps caused by a plush lining, thus keeping what water that is in the suit that has been warmed by the diver from exchanging back out. When you compare these three design differences from a typical wetsuit, you begin to fathom why these suits are warmer than your typical wetsuit.
This design concept has been taken one step further by a few companies. They have designed freediving semi-drysuits, which have waterproof zippers along the back, and you typically climb into them like a regular drysuit for scuba diving. Whether these suits are any warmer or more comfortable to dive in is up for debate.
What about the extremeties, your hands and feet.
Typical wetsuit boots and gloves usually work just fine. But there is emerging some designs that help to do what the freediving suits accomplish. Namely reducing the amount of water exchanging out of the neoprene coverd area of the divers body. Several manufacturers are producing gloves that have an extended gauntlet that is smooth-in neoprene, with an elastic band that can be cinched down snugly to almost eliminate completely water exchange. These are typically 5 to 7mm in thickness. Some companies produce what are called "three-fingered gloves". These gloves supposidly keep a divers hands warmer by allowing two sets of fingers to reside together in a finger pocket, helping to keep them warm. Boots without zippers are more difficult to take on and off, but they also reduce water exchange.
And since these are the areas furthest from the core of the body, extra thickness here is an actual advantage. Other options for the feet include wearing special dive socks that have a fleece lining that can be worn between you foot and neoprene boot. These are patterned after the dive skins tropical divers wear for scuba diving.
This is another product that can increase you comfort level for cold water diving.
The high tech dive skins utilize a windproof membrane that is sandwiched between a thin fleece lining with a tough lycra outside. Many have claimed that they have the equivilency in warmth of a 2mm neoprene suit. Worn underneath a wetsuit dramically increases the insulative prperties of your wetsuit. And since it isn’t neoprene, the suits are neutrally buoyant.
Other factors can contribute to staying warm when diving in cold water. What you consume for food before your dive can make for a pleasant or miserable day, depending on what you eat.
A meal that is high in carbohydrates, along with a low to moderate amount of fat is a good combination for keeping you body’s furnace stoked. The carbohydrates provide the immediate energy needed for diving, while the fats burn at a slower, yet steady rate to keep you going for that long day of diving. A large bowl of oatmeal, with raisens, brown sugar and a dollop of butter or margarine is a perfect example of this kind of meal.
The last tip is taken from what many cold water scuba divers have done. Bringing a large cooler of hot water to pour down there suits just prior to getting in the water. This eliminates the initial rush of cold water shocking your system , and let’s face it, IT FEELS GOOD on a cold day.
Just remember, cold water diving can be an enjoyable experience, if you know how to keep yourself warm during the cold winter days.