Deep-Six Underwater Systems, Inc.
"Add Depth to Your Life"

Table of Contents

1 Pressure and Gases
2 The Face Mask
3 The Snorkel
4 The Fins
5 Weight Systems
6 The Knife
7 The Wetsuit
8 Pressure and Water
9 The Ear and Pressure
10 The Sinus and Pressure
11 The Stomach/Intestine and Pressure
12 The Lung and Pressure
13 Barotrauma caused by External Air Spaces
14 The Buoyancy Compesation Device (BCD)
15 The Scuba Cylinder
16 The Scuba Cylinder Valve
17 The Regulator
18 Density and the Diver
19 The 4 Gas Laws
20 Hand Signals
21 Carbon Monoxide Poisoning
22 Hyperventilation
23 Nitrogen Narcosis
24 Diver's Flags
25 Sound Underwater
26 Color Underwater
27 Decompression Sickness
28 Breathing Oxygen
29 Deep Diving
30 Thermoclines
31 Thunderstorms
32 Underwater Life
33 Open Water Dives
34 The Final Examination
35 The Environment
36 Advanced Course

7 - The Wetsuit

          The less water entering a wet (or dry suit, for that matter) the warmer it will be. The common misconception is that a wet suit keeps the user warm because of the thin layer of water that enters it. That is false. The gas bubbles in the suit itself provide the insulation. In fact, the more water that enters the suit, the less effective the suit will be for maintaining warmth. Water is a tough commodity to warm up! Also, wet suits are designed to keep the diver warm, not make them warm. If you start out cold in a wet suit you will not be warmed up by the suit.

     In many suits, especially ones produced many years ago, the neoprene was not as flexible as with modern suits.If the older suits were made to fit close to the body the effort to inhale could become great enough to cause the diver to think they are out of breath. Therefore, it was necessary to wear a suit that was slightly larger in order to prevent body squeezes and constriction. That allowed more water to enter. The manufacturers told the buyers and instructors the false information about how the the layer of water kept the diver warm. The best suits allow the least amount of water to enter. At Deep-Six we try to fit the customer with a suit that is as close to the body as possible.

     Some customers ask, "What happens to a suit as it ages?" "Does it shrink or expand?" The answer is that the suit remains just about the same for many years. Deep-Six has a few wet suits that are over 25 years old. They are used only in chlorinated pools. They are just about the same as when they were new. So, it not the suit that changes over time. It is usually the wearer!

     Wet suits come in a variety of thicknesses that range from less than 1mm to more than 7mm. The thicker the suit the warmer it will be underwater. However, the thicker the suit the more bulky it is and the more buoyant the diver will be. Typically, for tropical diving in water that is 80 degrees or above a 1mm to 3mm suit would be best. For diving in northern waters, such as New York State lakes and the ocean in the Spring and Fall, a 7mm suit is ideal. The thickness and type of suit will depend on how fat the diver is. Fat divers have a lot of very adequate insulation and will be able to use a thinner suit. For most divers, when diving in water that is less than 40 degress a dry suit would be preferable.

     Wet suits get thinner as one descends. Since the suit is composed of millions of gas bubbles, as the diver goes deeper the bubbles compress and the suit does not provide as much insulation as it does on the surface. A suit is about 1/2 the original thickness at a depth of 3 atmospheres (66 feet in seawater, 68' in fresh water - remember it's not just bubbles that would be half the size at 33', but the suit has matrix as well). Not only will the diver feel the cold more, they will have lost buoyancy and be overweighted.

     Since wet suits are waterproof it is impossible for a person wearing one on land to loose body heat by evaporating sweat. Even in warm water a diver can become over-heated (hyperthermia). It is possibly for a person to suffer from heat stroke if they wear a suit and become too hot. Standing in the sun with a thick suit, or exercising in a suit in or out of the water may result in overheating. Some divers remove their hoods (at least) to keep this from happening.

     When one is finished using a wet suit it should be rinsed with fresh water. The suit may even be washed using regular laundry detergent in a washing machine. However, it is not wise to expose the suit to chlorine that is found in pools and bleach. Do not out it in a dryer! It should be hung up to dry with the inside out, away from the sun and ozone (officers copiers, electric motors, etc.). The hanger should be thick. Thin coat hangers, as well as folding the suit, will leave permanent creases in a suit. Once it is dry it may be hung with the outside out in a closet.


          Size                   Height             Weight            Chest          Waist          Hips


5'4" - 5'7" 125-145 lbs 34"-36" 30"-32" 34"-36"
Medium 5'7" - 5'10" 145-160 lbs 36"-38" 31"-33" 35"-37"
Medium/Large 5'8" - 5'11" 160-175 lbs 38"-39" 32"-34" 36"-39"
Large 5'10" - 6'2" 175-190 lbs 39"-41" 33"-35" 38"-41"
X Large 5'10" - 6'2" 190-210 lbs 41"-44" 36"-39" 40"-43"
XX Large 5'10" - 6'2" 210-225 lbs 44"-47" 39"-42" 42"-45"
XXX Large 5'10" - 6'2" 225-240 lbs 45"-48" 42"-45" 44"-47"


       Size               Height                 Weight           Chest          Waist         Hips

4 (XXS) 5'1" - 5'3" 90-105 lbs 29"-31" 22"-24" 31"-33"
6 (XS) 5'2" - 5'4" 110-115 lbs 30"-32" 23"-25" 32"-34"
8 (S) 5'3" - 5' 5 1/2" 110-130 lbs 32"-34" 25"-27" 34"-36"
10 (M) 5'4" - 5' 7 1/2" 125-140 lbs 34"-36" 27"-29" 36"-38"
12 (L) 5'6"  - 5'10" 135-150 lbs 36"-38" 29"-31" 38"-40"
14 (XL) 5'8" - 5'11" 145-160 lbs 38"-40" 31"-33" 41"-43"

Copyright Information about this text, DIVING WITH DEEP-SIX is as follows: Copyright 1996 - 2007 by George D. Campbell, III; President. All Rights Reserved. This file may be posted on Electronic Bulletin Boards for download, but may not be modified, printed for distribution, or used for any commercial purpose without the author's written permission. is using this material with the permission of Deep Six. The full version is available at:
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