Dry Suit Diving: Staying Warm in Cold Water
Introduction
When I left Thailand, I had no idea where or when I'd be able to dive again. It seemed like I'd have to say goodbye to diving for a long time. After all, Belgrade isn't by the sea, and the nearest convenient diving spots are in neighboring Montenegro, where the season only lasts six months a year, and trips require advance planning. But I wanted to dive more often…
After three months without diving, I finally found a way to keep diving even in my current situation. True, it meant learning to use a dry suit – diving in winter without one is tough. But luckily, I enjoy learning! 😊
I'm not an expert in dry suit diving yet, but I've grasped the basics and want to share my impressions.
The Difference Between a Dry Suit and a Wet Suit
The difference between a wet suit and a dry suit seems obvious: in a wetsuit, you get wet; in a dry suit, you stay dry. Magic? Almost! ✨
But seriously, the difference isn't just about how wet you get. Wetsuits are simpler in design and allow for easier movement. In a wetsuit, water gets trapped between your skin and the material, then warms up using your body heat. Most divers use wetsuits.
Unlike a wetsuit, a dry suit is completely sealed, isolating your body from the water. Using such a suit requires additional skills, preparation, and care. There's another significant difference – the price. Dry suits are considerably more expensive, but with proper care, they can last for years. So, it's more of an investment than an expense.
The primary distinction between wet and dry suits lies in their suitability for different water temperatures. Depending on thickness and personal cold tolerance, neoprene wetsuits are popular in tropical and temperate regions. However, at temperatures below 10°C (50°F), extra protection becomes necessary – and that's where dry suits come in.
What is a Dry Suit and What is it For?
A dry suit is specialized diving gear that allows the diver to remain dry.
Key Elements of a Dry Suit
Waterproofing
Dry suits come in two main types: membrane (or shell) and neoprene. Membrane suits are lighter and more flexible but require good undergarments. Neoprene suits are warmer but slightly restrict movement. To prevent water entry, watertight seals are used at the neck and wrists. Modern dry suits wouldn't exist in their current form without the invention of the waterproof zipper. Regular zippers leak, while waterproof ones are modifications of airtight zippers developed for space suits. Real rocket science! And yes, it's the most expensive component of the suit.
Insulation
The air inside the suit also helps retain heat, but it's not enough to protect against the cold, so good undergarments are essential. Thermal underwear or an undersuit is worn underneath. The colder the water and the longer the dive, the warmer the undersuit needs to be. The selection is vast: from simple solutions to professional sets – everyone can find something suitable.
Valves
The primary tools for buoyancy control are the valves. The system is simple: air enters through the inflator valve (usually from the tank), and excess air is removed through the exhaust (or dump) valve.
Gloves, Boots, Hoods, Pockets
Additional elements like gloves, boots, hoods, and pockets make diving not only warm but also convenient. Pockets are particularly useful: you can store anything you might suddenly need at depth.
When is a Dry Suit Needed?
A dry suit is used in situations such as:
- Diving in cold water (temperatures below +10°C / 50°F), where a wetsuit no longer provides sufficient comfort.
- Long dives, as it retains heat even during extended periods underwater.
- Challenging conditions: ice water, polluted waters, or strong currents, where staying dry and protected is crucial.
Air is typically used inside a dry suit, but technical divers also use argon. Air has lower thermal conductivity than water, and argon has even lower conductivity, which is why it's used in technical diving for better thermal insulation. As a result, heat is retained longer, making even extended dives comfortable.
Furthermore, special undersuits are worn under dry suits to help retain heat. The right undersuit allows comfortable diving in both icy water and temperate latitudes where a wetsuit might not always suffice.
Types of Dry Suits
Dry suits vary, and each type is suited for specific conditions and tasks. There's no universal answer to which suit is best; it all depends on your needs, diving conditions, and even personal preferences.
Membrane (Shell) Suits
Membrane suits consist of several layers, with the central layer being a waterproof membrane that provides protection from water. The most popular membrane suits are made from trilaminate material, originally developed for military purposes. Now, this material is one of the most sought-after for dry suits. Civilians borrowing tech from the military again!
Trilaminate is a three-layer material that comes in different thicknesses. These suits are reliable, have a long lifespan, and dry quickly, making them convenient for repairs, transport, and storage. Additionally, they are lightweight and compact (though still bulkier than a wetsuit).
However, membrane suits have a drawback – they offer virtually no thermal insulation. Therefore, choosing the right undergarment is especially important when using them.
Neoprene Suits
Neoprene dry suits resemble wetsuits but with one crucial difference – they don't let water in. The material is the same as in wetsuits but is treated to be watertight. These suits have inherent insulating properties, so in warmer water, an undersuit might not be needed at all.
Neoprene suits are stretchy and soft, providing comfort even during long wear.
Although neoprene suits offer good insulation, they have characteristics to consider. They require more weight due to positive buoyancy, lose some insulation at depth, and take longer to dry than membrane suits.
Furthermore, over time and with wear, the properties of neoprene noticeably degrade.
Hybrid Models
Hybrid suits are a compromise: they are lighter than neoprene but warmer than membrane suits. However, like any compromise, they aren't perfect and fall short compared to other models in specific aspects.
Seals: Neoprene, Latex, or Silicone
Besides the main suit material, details like the seals, which ensure watertightness, play a crucial role. Seals at the neck and wrists prevent water from entering the suit. They can be made of neoprene, latex, or silicone.
- Neoprene seals are the most durable but stretch over time. Their thickness can make pulling them over your head inconvenient.
- Latex and silicone seals are more flexible and easier to replace if needed.
Training courses cover this extensively, so over time, you'll figure out which seals are most comfortable for you.
How to Choose a Suit for Your Conditions?
Choosing a dry suit depends on many factors – from water temperature to diving conditions. Here are the main points to consider:
- Water temperature. For cold water, neoprene or hybrid models are better; for warmer water, membrane suits with light undergarments are suitable.
- Dive duration. The longer you stay underwater, the more insulation you'll need.
- Diving conditions. If you anticipate extreme conditions (ice water, strong currents), choose a suit with enhanced durability and protection.
- Transportation. For travel, lightweight and compact membrane suits are best.
If possible, definitely test different types of suits. This will not only help avoid mistakes but also ensure the chosen suit is truly comfortable and matches your diving conditions.
Dry Suit Diving Training
One of the main differences between wet and dry suits is the need for additional training. For example, you can take the PADI Dry Suit Diver course or, as in my case, the SDI Dry Suit Diver course (It just so happened that I took this course with a different diving association). {/ Kept your original links /}
With a wetsuit, it's simple: put it on, adjust your weights for the neoprene thickness, and get in the water. But a dry suit isn't that straightforward – it requires additional skills.
What Do They Teach and Why?
Just like in a BCD, mask, lungs, or any other air space, the air inside a dry suit compresses and expands with changes in depth. To dive comfortably and safely, you need to learn how to manage this – that's what the practical part of the course focuses on.
Key Skills:
- How to properly manage air inside the dry suit and the BCD, and when to use one over the other.
- How to prevent "suit squeeze" during descent.
- How to correctly turn your shoulder and/or raise your arm to vent air during ascent.
- What to do if you get inverted (upside-down) and all the air rushes to your legs, creating "bubbles" that pull you upwards.
Actually, all this is learned quite quickly, especially if you already have diving experience. The main thing is practice, and soon the dry suit will feel as familiar as a wetsuit.
Personal Experience
There aren't many dive centers in Belgrade, but they exist. On Google, I found three centers that showed some activity on their websites or social media.
The main challenge for me was finding an instructor willing to teach in English, as Serbian wasn't an option for me. I wrote to all the centers I found but only got a reply from one. Which was fine, I only needed one.
We met at their dive club, which they call the "Base." The Base is located in the basement of an apartment building but has a very atmospheric and professional feel: lots of gear and training materials, their own compressor for filling tanks, and even a small museum corner with retro equipment.
We discussed my experience, goals, what gear I had, and what I needed to rent. We had some rakia and agreed to meet in a few days for the theory part, and on the weekend for pool practice.
The theory was delivered as lectures with presentations. I wasn't given a physical or digital theory book. However, I had access to the PADI course materials, which became available after I earned my Divemaster certification. So, I studied the theory in two versions: PADI and SDI.
The practice session was memorable for its contrast. We were practicing dry suit diving in a huge public swimming pool, while nearby, kids were learning to swim, and further down, a water polo game was in progress. The sensation of diving in a dry suit was unexpected: easier than I thought, but completely different from what I expected.
I dived in a rented membrane suit, the Ursuit Softdura. The choice was simple – it was what they found that fit me. This model has a front zipper, thigh pockets, and integrated boots.
The material is a three-layer polyester with a butyl rubber membrane, making the suit durable and flexible. The telescopic waist construction with suspenders adds comfort. At least, that's what the website says =) I have nothing to compare it with yet.
The suit also had something called a P-valve. It's a special valve for... let's say, handling physiological needs during long dives. Without it, a "dry" suit might cease to be dry. How does it work? Honestly, I didn't look into it and didn't try it – didn't want to experiment with rental gear. 😅 But they say it's a useful thing.
After completing all the exercises and getting the hang of managing the suit, we got out of the water, and I noticed I was actually wet under the dry suit. The problem turned out to be the seal on my right wrist – it was a bit loose, and water gradually seeped in when I moved my wrist.
It wasn't critical, as gloves with locking rings were planned for the open water dive, but I decided to play it safe and asked for another session – this time in the full kit, including the thermal undersuit. The second time went perfectly, and we scheduled a dive at Ada Lake for the upcoming weekend.
The last Sunday of 2024. It's +2°C (about 36°F) outside, the grass is covered in frost, the streets are deserted, but the rising sun makes the morning magical. We meet in the park by the lake. Runners jog past us while we kit up for diving in the parking lot. It feels surreal! My buddy enters the water first and points out floating ice. I laugh nervously and follow him down. The water is icy, but the suit holds – I don't feel the cold.
A mix of excitement and anticipation. We descend... Brrr! Cold and thrilling at the same time!
The underwater world isn't as vibrant as in Thailand. During the dive, we encountered a few crayfish – and that was it. But it was interesting to observe the river weeds and the play of light. Honestly, I just wanted to understand what it feels like to dive in cold water in a dry suit during winter.
Conclusion
Dry suit diving is a completely different experience compared to using a wetsuit. Everything feels unfamiliar at first, but once you figure out buoyancy control, you start to really enjoy it.
Yes, dry suits have their complexities: additional courses, the cost, the need to monitor watertightness. But after my first dive in cold water, I realized it was worth it. Although, to be honest, I still prefer diving in a wetsuit for the greater freedom of movement.
But now I know for sure that the limits in diving are a matter of gear and skills, not weather. I want to dive more, explore new places, and try new things. Maybe someday I'll even get into technical diving. Who knows? 😉