Scuba Wetsuit

Scuba divers wear wetsuits principally for protection from the chilling effect of the sea, even in waters that are relatively warm.

If you have ever seen a diver wearing a full scuba wetsuit for a dive off the coast of Queensland or Western Australia when you thought the water temperature was just fine, there are a few things to remember. First, the purpose of diving is to go deep underwater, and that warm layer of water bathers enjoy at the beach is rarely much more than 10 feet deep.

Secondly, there is a big difference between being half-submerged in the water for several minutes at a time and spending 45 minutes straight completely immersed in it. Third, water is a much more effective conductor of heat than air, and cold water will literally bleed the heat off your body. 58 F is a crisp, cool day, but 58 F water is positively hypothermic without protection.

A scuba wetsuit is made out of the synthetic rubber called neoprene, which is usually woven with a small amount of another fabric such as Lycra for extra flexibility. Wetsuits work by trapping a layer of water between the wearer's body and the neoprene, making the water into an extra layer of insulation. The thickness of the neoprene determines how warm the suit is, and if the neoprene is thick enough they can keep out some truly bone chilling cold. The thickness of a scuba wetsuit is usually expressed in millimetres. The usual standard for water temperature and wetsuit thickness is:

• 75-85 F 1 mm
• 70-85 F 3 mm
• 65-75 F 5 mm
• 50-65 F 6.5 mm

A scuba wetsuit comes in a variety of formats, with the basic version being the one-piece full suit. These may or may not have an attached hood, and are sealed up by a zipper that runs either across the chest, across the back of the shoulders, or up the middle of the back. Shorty wetsuits are zipped up the same way, and are easily identified by their short sleeves and leggings. They are popular for tropical waters, and offer only minor protection from the cold.

Another option is the farmer john, which is basically a scuba wetsuit pair of overalls. The virtue of the farmer john in its flexibility, as it can either be worn on its own or in conjunction with a wetsuit jacket. The addition of the jacket creates a full wetsuit with variable thickness over the torso.

Complicating that picture are the mixed-thickness wetsuits. For example, there are full, one-piece wetsuits that are 3/5s, with a 5 mm torso and 3 mm sleeves and leggings. Rounding out the picture are add-on hoods for scuba wetsuits that do not have them built in, neoprene gloves and wet boots, or booties.