Fact: There are three different types of exposure suits available for scuba diving
When you go diving there are three main types of exposure suits available, each have their own features and variations: body suits, wet suits and dry suits. As you dive in different climates you will most likely come across these different types of suits.
Body Suits (or ‘Skin Suits’)
Body suits are mostly one-piece light weight suits which are usually made of stretchy fabrics such as Lycra. The main aim of body suits are to protect you from sun burn and accidental grazes. However some may also have a small amount of thermal protection. Some divers wear body suits under a wet suit as it helps the wet suit slide on more easily and can also add a bit of insulation.
Wet suits are by far the most used type of exposure suit as they come in many different thicknesses and can be used in many different climates of water (I’ve even seen divers use them in the UK in February!). Wet suits are made of a neoprene foam which is similar to a sponge however the bubbles in the material don’t connect to one another (called closed cell foam) this is why wet suits don’t absorb water. The closed cell bubbles however do trap nitrogen or air which is good for insulation and is also why wet suits are buoyant.
When you start your dive water seeps in between the wet suit material and your body and gets trapped there. Your body will heat the water and provided there isn’t any circulation the water won’t contribute to any further heat loss.
The thicker the neoprene the better the suit insulates, provided the suit fits you properly. Any lose areas in the suit allow water to circulate and carry heat out of the suit and this compromises the suits effectiveness.
The worst part of diving in a wet suit in cold water is the rush of cold water entering the wet suit as you get into the water, however your body quickly warms it up!
A dry suit is similar to a wet suit however it is sealed and therefore does not let any water into it (hence the name: dry suit) Dry suits come in many different types and materials. Normally dry suits protect the whole body except the head, hands and feet, however it is possible to have all of these covered as well (e.g. my dry suit has socks attached, but no gloves nor hood). You would often use dry suits in water temperatures below 15°C, for extended periods of immersion in water which may be above 15°C, or when working in and around hazardous liquids.
Dry suits are made to stop water entering (however if the dry suit is ill fitting or has a hole in, it will leak – and cold water entering is not pleasant!). Dry suits can be uncomfortable in warm air and are typically used only in cold water. It is important to do a course in using a dry suit as there is an extra layer of complexity due to dry suit “squeeze”. Divers must inflate or deflate air from the quit in order to avoid this suit squeeze (a suit squeeze isn’t pleasant either) serious suit squeeze can also be fatal if the diver became negatively buoyant resulting in an uncontrolled descent.
My Diving Wardrobe
Personally I will always try to wear a scratch vest and shorts when I dive during the summer in a hot country, if this is not an option then my second choice will be a thin wet suit. Last week diving in Turkey I was wearing a 5mm wet suit with hood, the water generally varied from 23-25°C (depending on how much it had rained) and after two one hour dives in the morning I would be very cold, but stubborn old me refused to wear the hood until the second week of our stay.
I have dived in the sea in the UK in a wet suit, and I have to say it was NOT a pleasant experience, I didn’t wear a hood nor gloves so my brain felt as if it had frozen over but it was an awesome dive as the visibility was generally ok and there was a surprising amount of aquatic life to see. I would have definitely enjoyed the dive even more if I had been wearing a warmer exposure suit!
I have done a few dives in a dry suit and honestly I absolutely love it! Wearing (pretty much) a bag filled with air enables you to play around with buoyancy a lot and I really enjoy that freedom of being able to move the air around the dry suit to help improve trim under water. What I also enjoyed was the ability of spending an hour underwater and coming out of the water pretty much completely dry.
At the end of the day its really up to you what exposure suit you wear, I have seen divers enter water which is 1°C in February wearing nothing more than a 5mm wet suit, which for me wasn’t enough in water 23°C! Depending on what water you’re used to diving in may therefore impact the exposure suit you wear, if you’re ever in doubt go with what dive masters and instructors wear because in some locations they are in the water every day and therefore often wear sufficient exposure suits for diving on that site.