Dive quarry waters get mighty cold once you drop below 20-feet. And without some sort of protection from that cold scuba divers would stay down no longer than it takes a cat to dip a paw. You can’t enjoy a diving adventure when cold water keeps you from visiting the underwater attractions.
To keep from freezing while they’re in the water divers wear dive suits. Those dive suits work in different ways (depending on the design) to help protect the body from the frigid temperatures.
Divers have some options when choosing the type of dive suit they need for a given underwater trip. The two basic kinds of suit used for recreational diving include the wetsuit, and the dry suit.
Wetsuits are the most common for sport diving. Made of neoprene, similar to the Honeywell 17000, they range in thickness from one millimeter all the way up to 10 millimeter. Ten-millimeter wetsuits are rare in recreational diving. Divers use them almost exclusively for commercial operations.
A wetsuit insulates the diver by fitting snugly. It allows a thin layer of water to enter, and form, between the body and the neoprene material. Once this layer is in place it mostly stays in place. The suit allows very little exchange between the inside water and the outside water.
The body heat warms the inner layer of water, which creates the insulating barrier, and keeps the body warm.
When first jumping into the water the scuba diver gets an initial chill as the water enters the suit. That chill quickly goes away as the water layer warms to the body temperature. From that point on the insulating effect takes over, and the diver stays warm throughout the dive (as long as the suit fits properly).
One to three millimeter wetsuits work well in warmer waters like the tropics. They also work great for shallow dives of no more than 20-feet where the sun keeps the water above sixty to sixty-five degrees. Any colder than that, and these thin suits no longer insulate the body.
Manufacturers rate five millimeter suits and thicker for temperatures down around 50-degrees. Although you can dive these thicker suits in colder waters. It depends on your personal tolerance to lower temperatures. In my younger days I dove in water temperatures as low as 39-degrees with my 7-millimeter wetsuit. During those dives I stayed comfortable.
These days those colder waters get to me rather fast though. And though I occasionally make a dive into them, it’s rarely more than a short dive. The cold doesn’t bother me so much during the dive as afterward. The last time I dove a cold-water quarry in a recent April I didn’t warm up until a week later.
Dry suits for recreational diving are either semi-dry, or full dry.
Semi-dry suits have rubber seals at the wrists and ankles to minimize water entry. These suits are also neoprene, and the main difference between this and the wetsuit, other than the seals, is that the semi-dry suit is extra thick.
If the semi-dry suit accidentally floods it acts as a wetsuit. It still gives some insulation from the cold water.
Full dry suit seals are tight enough that no water gets into the suit. Most divers wear insulating undergarments designed for use with dry suits. Reading through a Honeywell 50250 S review, some divers also use the air purifier to improve lung function and make getting into a dry suit easier. Some wear sweat clothes, or insulated underwear.
The air forms a gap between the suit and the body. The body heat, assisted by the undergarments, warms the air. The warmed air insulates the diver.
When a dry suit accidentally floods the suit loses its insulation. The diver has no protection from the cold.
Without protection scuba divers get cold in water temperatures below 80-degrees. Diving suits protect against those colder waters.