>Another benefit drysuits offer is improved ability to maintain neutral buoyancy throughout the water column. The diver can add gas to the suit using a manual inflator valve, and excess gas is purged through an exhaust value positioned near the top of the suit. In general, a drysuit should not be used as a buoyancy device in place of a BCD, particularly in emergencies; divers should add just enough gas to the suit to avoid suit squeeze and make sure to vent excess gas when ascending. Compared to wetsuits, they generally require more weight to submerge, depending on the undergarments worn. Like other diving technologies, drysuits require both training and practice; most training agencies offer a drysuit course.
>Shell suits, particularly those made with trilaminate, tend to be lightweight and flexible and can therefore be worn all day without physically exhausting the diver. They are easier to don than neoprene suits and dry faster. In addition, because the shell itself offers minimal thermal protection, the suit is ideal for diving over a broad range of water temperatures, from near freezing up to 70 or 75 degrees, depending on the undergarments used. The trilaminate shell suit is probably the most popular among technical divers, though many wreck divers prefer the heavier-duty crushed neoprene.
>Drysuits' watertight neck and wrist seals come in two varieties: latex and neoprene. Latex, which can stretch up to 400 percent, generally creates a better seal and is easier to put on and take off. They require more careful handling, though, and have a shorter life expectancy, requiring replacement when they wear out. Neoprene seals, which usually include a Lycra lining, expand by only about 100 percent and are harder to get on and off, but they hold up longer and can take more abuse. Latex seems to be the preferred choice for most tech divers. One of the latest innovations in drysuits is Diving Unlimited International's (DUI) patented "zip seals," which snap into place rather than being glued, allowing them to be changed out in the field if necessary.
>A feature that makes a nice addition for cold-water diving is a warm neck collar overlay, and some divers wear a silk scarf underneath. Another option for really cold water is dry gloves, which are worn at the cost of some minor dexterity loss. A word to the wise: Warm, dry hands are divine. Several additional features to consider are bellows pockets (with Velcro flaps and enclosed bungee cords for securing items), crotch pads and kneepads.
>If you plan to stay hydrated, which is critical for safe diving, you will need a way to relieve yourself while wearing your drysuit. If diapers aren't your style, the P-valve system consists of a balanced dump valve, mounted on the suit near the inside of the thigh, which is attached to a length of rubber tubing. Men attach the tube to a self-adhesive condom catheter, and they're good to go. Women wear a self-adhesive external catheter cup, such as the She-P.
>Suitable undergarments are typically made from synthetic fleeces like Polartec or Thinsulate. Be sure to select undergarments designed for the water temperature(s) you plan to dive in. Layering is often a good choice. Also consider choosing materials that maintain their thermal properties when wet in case of a suit flood or serious leak. Drysuits are rarely 100 percent dry. Despite modern materials and advanced designs, they can leak, and moisture and perspiration can accumulate. Sometimes getting wet means getting wet. Ultimately, however, the thermal benefits of drysuits are unmatched. Whether you're trying to extend your dive times or your dive season, diving dry might just be the way to go.
>© Alert Diver — Winter 2012