Wetsuits 101
By Brian Bradley

There is a great deal of mystery and few facts based on scientific testing concerning what constitutes a superior diving suit. The information contained in this article is based on personal experiences as a free diver since childhood and a commercial diver for the oil industry in the seventy's. Utilizing mixed-gasses and working in depths exceeding four hundred feet of water the dive suit was my protection from the elements while welding support platforms for Well Heads. It has been my pleasure to manufacture innovative, top quality diving suits for the commercial, scuba and free diver in Hawaii and on the mainland for the past twenty years under the Deep Thought™ trademark.

A Little History
In the 1950's neoprene was developed primarily for plumbing insulation. The properties of neoprene were far superior to the thin walled rubber that was being used at the time as protection from the cold and the reef. Much like an innertube for a bike tire this thin walled rubber was stretched carefully over long underwear. Where the innertube like rubber material offered water tight protection and the long underwear was used as the insulation for warmth, neoprene had both protection and warmth plus it stretched very well, resisted abrasion better and conformed to the shape of the diver.

This new neoprene material was called "closed cell" which appeared as smooth skin on the inside and the outside of the dive suit. This closed cell or "skin" suit is still used today primarily with competitive free divers. The theory behind the smooth skin outer surface is that there is less resistance through the water and consequently a diver can go deeper with less effort. This skin/skin neoprene is very flexible but is not resistant to abrasion and it can't hold a stitch, only glue. I remember many times between dives I would have to repair a knee or an elbow on the deck of the dive boat.

Shapes and Patterns
Through the years many people have asked me what it takes to make a top quality suit. The answer has always been the same, to use a true anatomically designed pattern shaped as the diver would be naturally in the water, to use the finest grade of neoprene available and to use quality, experienced craftsmen to assemble the suit, double coat all seams with glue and carefully stitch all seams.

To Fit Or Not To Fit?
The anatomical pattern is the key to a diving suit working properly. If the suit is not shaped properly it will work against the desired movement of the diver creating fatigue and chafing. A proper fitting dive suit will help maintain regular body temperature by allowing a small amount of water between the surface of the divers skin and the inside of the suit which the body quickly warms the thin layer of water. If the suit doesn't fit properly there is a constant exchange of the cooler outside water with the warmed water inside the suit. The secret to making a warm suit is to trap the warmed water inside and keep the cooler water from flushing thru.

Open Cell Neoprene
By slicing the neoprene much like a loaf of bread, which exposes the cut cell surface, allows for maximum lateral stretch. The drawback of open cell neoprene is that bacteria tend to grow on the open cell surface, which can cause serious skin problems. Also the open cell material, much like a sponge will allow water to pass thru. Lastly the durability of an open cell type suit is poor especially if a low grade of neoprene is used. It is common to see seams tearing out and the material overstretched or sagging.

Closed Cell Neoprene Smooth Skin
The closed cell smooth skin neoprene is the most commonly used for diving suits today because water will not pass thru the material. The smooth skin membrane is usually used on the inside of the diving suit to limit water travel. Smooth skin allows for good stretch, no chafing or skin rash and is simple to maintain.

Coated Titanium Closed Cell Smooth Skin
The coated titanium skin neoprene is reputed to reflect the body heat between the inside surface of the suit and the divers skin. This special treatment also allows easy entry into the suit without powder or soapy water. Titanium film coatings are offered in a variety of colors, which includes silver, gold and charcoal which are currently very popular in free diving suit manufacturing. It is very important to note that the titanium coating can be applied under the exterior fabric laminates. An example of this double-sided titanium coating can be seen on the Deep Thought's™ latest line of diving suits.

Laminated Neoprene
Laminated neoprene refers to a type of fabric such as nylon, Lycra, terry or a rougher material such as Kevlar™ or Rough Tex™ actually laminated to the surface of the raw neoprene. These laminated fabric surfaces offer abrasion resistance to the neoprene but conversely limit the stretching ability. In addition the tougher the fabric laminate, the less give or stretch the neoprene has. For example, Kevlar™ has almost no stretch so is suitable for the knee or chest (cocking pad) area only. Nylon stretches quite well unilaterally but is not as durable as Kevlar.™

Neoprene Density
The density of neoprene refers to its ability to resist flattening out under pressure, in this case as a diver descends. If you would, imagine thousands of tiny neoprene bubbles tied together by the wall structure of the bubbles. The ability of the neoprene bubbles to maintain their shape under pressure largely determines how warm the suit stays at depth. A suit that flattens out under pressure allows water flow through the suit as the diver descends. Again this point reiterates the importance of quality neoprene.

Overall Neoprene Quality
Many suits today are made with cheap "gumball" neoprene, which is easy to put on or take off and is easy to swim in while the suit is still new. The tradeoff is these suits flatten out under pressure and tear very easily. Also the once well-fitted new suit begins to sag and stretch due to the inability of the cheaper neoprene to recover from repeated compression while free diving.

Thermal Value
Thermal value is the ability of neoprene to hold the heat generated by the divers body and is also related to the neoprene bubbles and the ability of them to recover from repetitive dives as mentioned earlier. The amount of gas or air that's trapped in these bubbles is the real insulation against cold and has a lot to do with how warm the suit is overall.

Overlock Stitch
This is a "quick and dirty" way to make a diving suit. Two edges of neoprene are held together side by side and than run thru a machine that whips a stitch over the edge to form a seam without the use of any glue. This seam isn't waterproof and tends to cause skin abrasions due to the ridge created by the edge of the neoprene when stitched. When viewed from the outside the seam looks smooth but when examined on the inside a ridge of stitching shows, which translates as lines on your body after a short exposure in the water. This type of dive suit is to be avoided because the choice of stitching by the manufacturer is a dead giveaway that cheap materials were used to construct the suit.

Flat Stitch
Overlapping the edges of the neoprene and running four rows of stitching along the overlapping pieces create a flat stitch, simultaneously trimming the edges or excess neoprene giving a more uniform look. Although this is a secure seam it is still not waterproof because again no glue is used same as the over lock stitch as mentioned earlier. One major drawback is the inconsistencies in sizing due to the overlap and cutting process.

Blind Stitch
Truly the best way to fabricate a dive suit is to blind stitch it. After the neoprene is double glued a skilled operator runs each seam thru a machine using a curved needle nipping the surface of the seam. The depth of the curved needle is set by the operator according to the thickness of the neoprene.

Quality in Materials and Fabrication
The words "quality in materials and fabrication" are associated with superior diving suit manufacturing. Through the years I have learned that profit and price-point has taken over from quality and pride. Unfortunately greed, ego and profit have ruined many fine products that quite possibly started as an affair of the heart and a passion for the sport. Ask yourself this question next time your trying to decide on your next dive suit; how can a dive suit manufacturer pay to advertise worldwide, sponsor several diving teams and events worldwide, sell to wholesalers who then sell to retailers and have any quality left in their product?

About the Author
Brian Bradley is the founder of The Blue Water Hunter in Kailua-Kona Hawaii and The Blue Water Hunter. He is also owned Deep Thought™ for over twenty years. Deep Thought™ makes standard and full custom dive suits for commercial, scuba, and free divers worldwide. Free diving since childhood he has also worked as a commercial diver in the 1970's. Other interest includes surfing, paddling and real estate.