First comes the theory, then comes the practice.

Understanding how the physics of being underwater affect the body and how to deal with these effects is essential if you want to become a commercial diver.

It’s for this reason that The Divers Institute of Technology (DIT), in Seattle dedicates such a large part of its commercial diving courses to teaching divers all they need to know to master the physics of underwater work.

Working in any underwater environment is a challenge even at the best of times.

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Divers have to contend with everything from decompression sickness to nitrogen narcosis on a daily basis.

Let’s take a closer look at exactly what divers have to learn before they can take to the water.

Hitting the Books before Hitting the Water

Like it or not, commercial diving students have to do a lot of bookwork.

While the thought of going back to school is less than exciting for many of us, it is essential if students are going to learn how to dive safely.

The Divers Institute of Technology’s Physics & Medicine course is without question one of its hardest modules.

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As DIT instructor Bradley “Pete” Peterson puts it, “The hardest part is that there is so much information to absorb. The math isn’t really that hard, but just the amount of information in the short time is what is the hardest.”

Overall, the intensive in-class modules are only one month out of the 7 month long training.

First, Physics

Students will barely have settled in before they are thrust into the classroom where they’ll stretch their brains learning all the Gas Laws.

In fact, the first 6 days of their training are entirely dedicated to physics.

Explaining Gases and Pressure

There are multiple laws which explain how gasses behave under different pressures. They include:

• Boyle’s Law: As pressure increases, volume decreases

• Dalton’s Law: The total pressure applied inside an inert gas is equal to the total pressure applied

• Gay-Lussac’s Second Law: As temperature increases, pressure increases

• Henry’s Law: The volume of gas that can dissolve into a liquid is proportional to the partial pressure of the gas

• Charles’s Law: As temperature increases, volume increases

Water, the Body, and Decompression

After learning these laws, students will then go on to learn other rules of being underwater including the process of decompression. And, here are a few other laws you’ll need to learn and apply to diving, including:

• Snell’s Law: The refraction property of water is 30% greater than air and similar to that of the cornea of the eye

• Archimedes’ Principle: An object that is immersed in a fluid will be buoyed up by a force that is equal to the weight of the fluid it displaces

Following this, the DIT instructor explains how to dive safely. This section includes everything from how to enter and exit the water to using dive tables correctly.

Medicine: Ready for any Emergency

After students have mastered 6 days of physics, it’s on to medicine. 

For 6 days, students will learn the application of the gas laws and how they are used to dive safely.

Every physical condition such as nitrogen narcosis will be broken down to examine exactly what it is and how it affects the body.

Importantly, students will learn how to avoid these medical conditions, where possible, and how to cope and treat them when they do arise.

This knowledge saves lives.

Another part of this section is a swim test that makes sure that students are ready to move onto the next modules where they will put all the theory that they have learned into practice.

Last but not least, students will get to learn about the hyperbaric chamber and how different pressures affect their bodies.

Once students have completed all these parts, it is time to gear up and get wet.

Taking The Plunge

DIT’s commercial diving course continues with another 6 modules.

During these modules, which in total will last 7 months, students will get hands-on training on everything from how to manage their buoyancy to learning to weld underwater.

Instructors will teach students everything they know to get the job done safely.

Ready for Deep Dives

Deep Dive Module 7, the final module, involves students learning how to undertake deep dives below 60 feet. 

This is where all the hard bookwork from the first module really comes into play.

After getting familiar with the decompression chamber, students will head out to Lake Washington where they will get to do three dives at 60 feet, 5 dives at 130 feet, and 2 dives at 160 feet.

This module exposes students for the first time to the effects of decompression and nitrogen narcosis, which can be deadly.

But rest assured, every step of the way, dive students are supervised by experienced instructors who are veteran commercial divers themselves.

By the time that students graduate, they are more than prepared for anything that working underwater can throw at them.

Aran Davis, Writer for Water Welders