With a dark bold look of a diver in full gear, diving with dry-suit could never be more intriguing. Most Thai divers may have thought there is only one solution to keeping themselves warm or making themselves look great, nah… you are way wrong. Wetsuit is common, but being “dry” could suit your discerning diving taste, even better.
Just about most dry-suit divers recall how they might have hated their first few dry-suit dives but once you past the initial pain they don’t look back and never want to dive wet in cold water again. I could think of more than a just few numbers of reasons we dip into the water without getting wet.
Firstly, it’s again about the safety, shunting from extremities, expel fluids, reduce volume, nitrogen trapping. Then of course it’s the suit that keeps you warm in the water, between dives and upon exit. Diver also breathes easier and air last longer as physiological changes reduced. Last but not least it is surprisingly “less expensive” than wetsuits (I am serious!).
And you know what? It’s not as difficult as it looks and you don’t need to stretch your adventurous palette as far as ice-diving to give it a try.
It is never be a surprise if first dry-suit experience for anyone would be an unmitigated disaster and they might just hate it. It could be uncomfortable, the boots could feel just too big and one might spend a lot more time drying and patching it than they may ever do diving in it. That’s some blast from the past. Recently most manufacturers make dry-suits cheap, light and with flexible sizes.
A dry-suit provides both insulation and buoyancy by surrounding the diver with air. However this air space will be subject to Boyles Law (still remember your basic?) and will contract with depth and expand on ascent. So, there is a need to be able to control the air within the suit and this is achieved using air from the cylinder via the suit inflate valve and loss of air via the dump valve..
During descent the suit will be squeezed against the diver’s body and may pinch the skin. It’s a bit of an itch. Air movement within the suit is termed migration and it will always travel to the highest point. So, air dumps are often situated at the shoulder or cuff and may be of an automatic or open nature. If it occurs that a dry-suit become filled with water it could hold up to a cubic meter or 1 metric ton of water. It surely does not sound like fun as exiting from water with such a load is extremely difficult.
There is a common misconception among dry-suit divers that a little bit of a dry-suit leak or just a little bit of moisture finding its way in is fine. It is not. Keeping warm in cold water is all about using the scientific principles of thermal insulation, conduction and dissipation along with an understanding of the human body thermal properties to your advantage. Unlike wetsuit, Dry-suit keep your head warm. Hands and feet are also important but the head is critical. The deeper you go the less a wetsuit insulates you. With regards to temperature, dry-suits are however unaffected by any depth. As physical movement generates body heat, you get that a lot more trying to control you movement thus generating a little more temperature in the closure.
Since diving in dry-suits began, the suits have been made in either a laminated shell fabric or with neoprene. The debate over which material is best has raged for years. Both materials have their pros and cons and there are also numerous variants of each type, all with their own specific properties.
When diving with a dry-suit, buoyancy control is the key to diving with fun. A dry-suit may contain air but it is not a lifejacket. A diver will soon realize that whilst a dry-suit may offer buoyancy, it also has a tendency to position the diver face down in the water. Air flowing around inside your dry-suit makes for a really unpleasant dive as buoyancy and trim are difficult to control. It’s mostly flow from the top part of the body into the legs and boots which leads to that horrible feet-up position which is irritating and potentially dangerous. Dry-suit divers know how dry diving buoyancy is pretty different and more difficult to control than wetsuit buoyancy. But you then have a second inflatable device in a rather strange shape with air flowing around in there.
All in all, you need a proper dry-suit training to be fun, so what? It’s not a walk in the park but it's most certainly do-able.
If you can go skiing in Japan or in the Swiss Alps, you definitely need a proper gear. If you love mountaineering in Tibet, you definitely need to be well-equipped. Basics are there to grab on.
Well, everybody does it, just everywhere from moderately cold to freezing water,
..and why can’t you?
The author is PADI qualified dry-suit Instructor