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wetsuits. Depending on the fit of your suit and the type of insulating underwear you use, you might need to wear more weight with a dry suit than with a wetsuit. Types There are many different types of dry suits. Dry suits can be made from foam neoprene, solid neoprene, or a variety of heavy-duty nylons with waterproof materials laminated to them. The foam neoprene suits are one-piece suits that have a waterproof zipper and seals at the wrists and neck. The suit itself provides insulation. This suit is warmer than a wetsuit made out of the same material because the inside of the suit is dry and the air in the suit as well as the suit itself provide insulation. The solid neoprene suit requires that undergarments be worn under the suit for additional insulation. The amount of insulation worn can vary depending on the temperature of the water. This suit is less bulky than the foam neoprene suit. The nylon-shell suit is loose fitting, which gives you greater mobility and comfort. The nylon shell suit also requires that undergarments be worn. Features Most of the options available for wetsuits, such as pockets, knife sheaths, and kneepads, are also available for dry suits. Other options made especially for dry suits include: • Dry hoods • Dry gloves • Attached hard-sole dry boots Because dry suits do not need to fit as closely as wetsuits, custom fitting is rarely necessary. However, the cost of dry suits is still greater because of the special watertight zipper and the other materials and labor needed to make the suit waterproof. Buoyancy Control While diving, you control the amount of air in your dry suit with an inflator valve, which allows you to add air to the suit, and an exhaust valve, which allows you to bleed air from the suit. The inflator valve is similar to the power inflator used on a BC. You add air to the dry suit as you dive deeper and then bleed air as you return to the surface. The most common location for the inflator valve is in the middle of the chest so it will not interfere with your BC jacket. The exhaust valve is a low-profile valve that usually automatically vents air as you ascend. A common location for the exhaust valve is on the outside of your upper left arm. Different valve models bleed air at different rates. A valve that vents quickly is better, because it allows you to bleed air from your suit faster. When you dive with a dry suit, you use the dry suit for buoyancy control and the BC for surface flotation. You use the BC for backup buoyancy control. You must be very careful if adding air to both your dry suit and the BC under water because it is difficult to control both pieces of equipment at the same time. You must always wear a BC with a dry suit. If you are taking your NAUI Scuba Diver certification course in an area of the world that normally requires dry suits (for example, Alaska or Canada) you will probably be diving in dry suits from your very first class. If this is the case, your instructor will present supplemental material and training so you will understand how to use your dry suit. If your class does not include training in dry suits and you decide to buy one, you need to take a NAUI Dry Suit Specialty course to learn how to use the dry suit properly. Hoods You lose the greatest amount of heat from your head, hands, chest and armpits, and groin. Therefore, thermal protection for your head is critical when you are diving. In cold water, you can lose a significant amount of your body heat through your head alone. For most cold-water diving, you can use a simple hood made from wetsuit material (figure 2-41). The hood can have an attached bib that tucks under the collar of your wet suit to keep your neck warm and help keep water from circulating in and out down the back of your neck. The warmest arrangement is to have NAUI Scuba Diver 40 Diving Equipment


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