Drysuits vs Wetsuits

Drysuit vs Wetsuit Diving in BC

Many people think that scuba diving in BC is a summertime sport, when in fact it’s a four-season sport, with a fascinating variety and cycle of life across the seasons.  Drysuits make it possible to dive comfortably all-year round.

A drysuit is a technical piece of equipment that a diver must operate and manage actively, unlike a wetsuit, which is worn passively for exposure protection.  Drysuits have advantages over wetsuits, but they introduce additional risks. A drysuit diver must develop a higher situational awareness and new motor skills to operate their drysuit effectively & safely.

A drysuit is a sealed air-vessel, with the seals being at your neck and wrists.  The suit is connected to the regulator’s first stage and to the air cylinder by a low-pressure hose, just like the inflator hose on the BCD.  The inflator button is located in the middle of the chest. The drysuit also has an exhaust valve, usually located below the left shoulder. The inflator and exhaust valves are both deployed using your right hand. This is because you need your left hand to operate the BCD.

A drysuit diver must actively add air to, and exhaust air from their drysuit throughout a dive, much like they do with their BCD. However, a drysuit is not a substitute for the BCD and should not be used as the primary vessel for buoyancy control underwater. There are several reasons for this, the first one being that a drysuit is not designed or constructed to act as a primary buoyancy control device. It has multiple possible failure points that could result in a catastrophic flood. It exhausts air more slowly than a BCD. A too-large air bubble inside a drysuit can shift quickly and dramatically, throwing a diver off-balance and risking an inverted, out-of-control rapid ascent. And it’s impossible to exhaust air from a drysuit when the diver is in an upside-down position. Therefore the safest way to operate a drysuit is with a minimum amount of air inside it to offset a squeeze and allow the diver to feel comfortable, with free movement of their arms and legs.

At VSds, we train clients to dive in a shell-style drysuit, which itself provides no thermal protection. The diver wears layers of long underwear, fleece and socks. These undergarments plus the air in the suit provide the insulation.

The PADI Drysuit Specialty course will introduce you to drysuits in general, and train you to operate a drysuit while adapting your buoyancy control technique. It’s a one day, two-tank dive, with a brief course manual to read prior to dive day. If you want to rent a drysuit in the future as a certified diver, then you will need to present this C-card as proof of training.

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Prospective divers often wonder what the water temperature is around Vancouver, and whether they should train and be certified to dive in a drysuit. The simple answer is that the water’s always cold and that a drysuit will keep you warm much longer than a wetsuit can. So you should learn to dive in a drysuit and wear one all year round.

The water temperature at depth doesn’t fluctuate very much thoughout the year, with a minimum temperature of around 7-8C in February and the maximum around 13C in August. In the summertime, there’s a thermocline with a surface layer of warmer water reaching about 16C. But divers pass through the thermocline on descent, down into the deeper, colder water.

Wetsuit divers will usually only dive comfortably in the July-September time frame, when the water temperature is warmest and, most importantly, when they can warm up in the sun between dives. For the rest of the year, wetsuit divers can’t warm up between dives, so they get cold faster on the second dive.  This results in a higher risk profile and short second dives. Often the second dive gets cancelled.

Meanwhile, drysuit divers must deal with the opposite problem. They can stay toasty inside the drysuit between dives when there’s snow on the beach, but risk sweating and overheating when the air temperature is above 15C. They enter the water to cool off, and get chilled by the perspiration on their skin.

In the wintertime, I recommend that divers wear a base layer of warm, perspiration-wicking thermals, with two pairs of the thickest, warmest Arctic socks. I also recommend wearing a lower-back heat wrap that will keep your core warm all day. A double layer of fleece is worn over top of this base layer. 

In the summertime, a diver can wear shorts and a t-shirt, or a light base layer, under the fleece.

Serious divers will tend to use dry-glove systems rather than neoprene gloves. Hands will stay warmer, longer.

Drysuits are much more expensive to buy than wetsuits. A good quality drysuit, with accessories including a hood, boots and dry gloves will cost $2,000-3,000. Most dive shops will rent drysuits for around $50-75/day, marginally more costly than renting a wetsuit.

Posted on June 10, 2018 .