Because water is so much denser then air your body loses heat 20-25 times faster in water then it does on land. In addition when scuba diving it is possible to scrape up against an old ship wreck or a coral head, which can cause cuts and scrapes. Exposure suits help you maintain your body heat underwater and also provide a layer of protection against the possibility of cuts and scrapes. Consequently, experienced scuba divers will wear exposure protection when scuba diving.
There are essentially three types of Scuba Diving Exposure Suits, the Scuba Lycra Body Suit, The Wetsuit or Wet Suit and the Dry Suit. Lets briefly compare the three.
The Scuba or Snorkeling Lycra Body Suit
A body suit protects scuba divers against incidental scrapes and stings, and reduces sun exposure. Body suits have little or no insulation, so they’re primarily for warm water. Many divers also find they help them slide into wetsuits more easily, so you may want one for temperate water diving. A lycra body suit comes in bright colors and usually fits skin tight. The body suit is also an excellent choice for snorkelers to avoid sunburn when snorkeling in warm water.
The Scuba Wetsuit
Wetsuits provide insulation as well as skin protection, and can keep you comfortable in water as cool as 50-60ºF to as warm as 85-90ºF . Wetsuits get their name because even though they keep you warm, you get wet – they trap a small amount of water between the suit and your skin that your body quickly heats. To work properly the wetsuit must fit snugly in order for it to trap and hold the water so your body heat can warm it up. Wetsuits for wind surfing or kayaking should not be used when scuba diving. Surfing and kayaking suits are designed to allow water to drain out when you get out of the water and consequently do not allow a scuba diver to properly trap the water long enough to warm it sufficiently.
Scuba Wetsuit Styles
The most popular scuba wetsuit is the jumpsuit or full body suit. It is a one piece suit that covers the scuba diver from ankle to neck. It is available in different thicknesses: 3mm, 5mm and 7mm. The thicker the suit the warmer it will be. Two piece scuba wetsuits are also available. These consist of a section that covers the legs and chest and are knows as the Farmer John or Farmer Jane depending on if it is cut for a man or women. A shorty is worn on top of that and offers a double layer of warm over the chest cavity.
Occasionally, the diver will wear the shorty alone or over a lycra body suit in warmer waters.
Always try on a scuba wetsuit before purchasing it. Always try it on with the same type of bathing suit you plan to use under it to double check proper fit. It must fit comfortably and yet be snug enough to trap water. Features such as deluxe linings make it easier to get into and out of.
The Scuba Wetsuit will lose its warmth with age and can also shrink in size if left out in the sun. Always rinse your wetsuit in fresh water after diving with it and never leave it to hang in direct sunlight.
Dry suits provide maximum thermal protection. Although primarily used in cooler water, in temperate water they let you make more dives and longer dives even if you could use a wetsuit. Dry suits get their name because they keep you dry, except for (typically) your head and hands, over which you wear neoprene wetsuit hoods and gloves. Drysuits provide the most warmth when scuba diving and the drysuit is also the most expensive of the three types of exposure protection.
Drysuits come in two basic styles: Neoprene Drysuit or the Cloth, rubber or Laminate Drysuit. The later is used with special insulating underwear to provide the right amount of exposure protection for the temperature of the water in which you are diving.
When scuba diving with a drysuit, your suit becomes part of your buoyancy system. It is therefore prudent to learn how to properly dive with a drysuit. The PADI Dry Suit Specialty course is an excellent way of doing this.
Which ever type of exposure protection that you choose, make sure that it fits properly, that you know how to properly use it and that it is appropriate for the climate in which you are scuba diving.