What is Deep Diving?

The underwater world is a magical, fascinating one and those of us who get to go deeper can see more of it. But what exactly is deep diving?

Defining the term “deep” is a mission in itself. The beginner open-water diver who can only go to 12 or 18 meters might think the advanced divers at 30 or 40 meters are doing an incredibly deep dive.

To a technical diver that can go to 90 meters, divers at 30 or 40 meters might look like snorkelers. Even more extreme are the saturation and commercial divers that regularly go past the 200-meter mark using atmospheric suits and taking days to decompress. 

For the sake of this article, let’s call “deep” the recreational limits which means decompression isn’t necessary. Theoretically speaking, an advanced diver who can go up to 30 meters is doing a deep dive, but if you do specialized training with one of the agencies, you might push that limit a little. For example, PADI’s Deep Dive specialty will allow you to get to 40 meters. 

Let’s take a look at what deep diving requires, the gear, training, and all kinds of fun stuff associated with going under! 

What are the Rules of Deep Diving?

Deep diving requires way more planning, especially if you are doing it as part of a multi-dive day. Your nitrogen profile might not allow for much bottom time, so be sure to stick well within decompression limits. Regardless of the type of dive, the bottom time and maximum depth cannot be exceeded in scuba diving

In addition, be generous in your gas calculations and err well on the side of caution. Dive according to the rule of thirds, which is one-third for your dive, one-third to get back up, and one-third left as a reserve in the rank. You certainly don’t want to run out of air at 30 meters, which will significantly endanger not just you, but your dive buddy as well. 

Deep Dive Gear 

The gear you need for a deep dive will be similar to a regular scuba dive. However, there are a few things that you might want to think about if you’re going past 30 meters. 

Dive Light – At 30 meters, you’ll lose a significant amount of light and color. A dive light can help illuminate your surroundings and bring some color back, especially if you’re doing underwater photography. 

Wetsuit – The water will be colder at 30 meters, so if you wear a shortie for a 15-meter dive, you might want to wear the next level up, which is a 3mm full suit. If you are already wearing a 3mm long up at 15 meters, you might need a 5mm.

Regulator – At 30 meters, the atmospheric pressure will be 4 bar, which is double what it is at 10 meters. Some high-end regulators are specifically designed to withstand higher pressure, and a poor-quality, badly-serviced regulator might free flow or malfunction at depth. 

Tank – Although you should have enough air left in your tank to safely ascend, some dive operators hang a spare bottle at the 5-meter safety stop in case anyone gets low on air. 

Knife – Getting entangled in seaweed, kelp, coral, or lines at 30 meters is not the same as at 10. If someone’s stuck at 10 meters, their buddy can easily ascend, get help, and descend to free the poor diver. 

However, at 30 meters, things get a little more complicated. Air runs out faster, and you might exceed your no-decompression limits if you’re descending again to administer help. To keep you and your buddy out of trouble, a high-quality dive knife might be a good thing to have. 

What’s the Difference Between Deep Diving, Snorkeling, and Scuba Diving?

One thing all these activities have in common is that they are conducted in the water, which is already a huge plus! However, they are distinct from each other, especially when it comes to snorkeling and diving. 

Snorkelers use a mask, snorkel, and fins, to stay facedown on the surface of the water, looking down at reefs or structures. Scuba divers descend to recreational depth limits of 30 meters in full scuba equipment which includes a tank, buoyancy control device (BCD), and regulators. 

Deep diving is basically a scuba dive, just to a greater depth. Recreational divers with deep diving training can go to depths of 40 meters with the same gear as a regular scuba diver would use.

However, when it comes to technical or commercial limits, things get way more complicated. Technical divers have very specialized equipment like twin tanks and rebreathers, allowing them to go to depths of 90 meters. They use different gas blends to avoid conditions like decompression sickness, nitrogen narcosis, and oxygen toxicity. Blends often include other gasses like helium and many of their dives will be decompression dives, during which multiple stops are needed, not just the 5-meter safety stop. 

Commercial diving is even more specialized, requiring hundreds of hours of training, tons of different equipment, and many days of decompression. For example, a dive to 200 meters can take up to eight days to decompress from! 

Benefits of Deep Diving 

Many experienced divers know that we start losing light when we descend, and the deeper we go, the darker things get. In addition, the lack of light means that the prettiest, most colorful corals that need UV light to grow are usually at shallower depths. That gloomy, eerie feeling isn’t for everyone, so why do deep divers do it? 

Firstly, some reefs get better the deeper you go. For example, wall dives often have pelagic fish like sharks and rays past 30 meters as these elasmobranchs like colder water. 

Secondly, some divers like the peace and stillness of greater depths, with nothing but the sound of you breathing into your regulator and blowing bubbles. 

Third, some dive sites, like many wrecks and caves, are located at greater depths, and being able to explore a structure thoroughly might require a deep dive. 

Lastly, it is human nature to always want more, and once you’ve tasted scuba diving, you’re almost certainly going to want to go deeper!

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