Types of SCUBA Tanks

Types of SCUBA Tanks
You've learned to SCUBA dive, and the time has come to purchase your own tank. A choice of tank is important, since it will determine everything from the maintenance time you spend on it over the next 15 to 30 years, the time you'll be able to spend under the water on each of your dives over that span, as well as the ease of transporting it around for the same period.

Aluminum

Most SCUBA tanks are made out of aluminum. Aluminum comes with its own set of advantages and disadvantages. As for the latter, aluminum tanks, being lighter, are typically more buoyant, meaning the diver must wear extra weights to prevent being pulled by positive buoyancy to the surface. On the other hand, when the diver is not in the water, carrying around aluminum tanks is a lot easier than lugging steel ones. Aluminum tanks are also less susceptible to rust than steel tanks. Aluminum tanks last around 15 years, and cost about half of what steel tanks do.

Steel

If your tank isn't aluminum, it's probably made of steel. A steel tank's heavier weight actually works to a diver's advantage, since no extra belt weights are typically required. The tank weighs the diver down all on its own. Out of the water, though, the weight of a steel tank can be burdensome. Steel tanks are more susceptible to rust than aluminum tanks, thus requiring more in terms of maintenance. Steel tanks last around 30 years. They are typically around twice as expensive as aluminum tanks.

Low Capacity

Whether your tank is steel or aluminum, it will generally come in one of three sizes--or capacities. Low-capacity tanks hold 2400 to 2640 psi (pounds per square inch). Though many factors--like workload, depth, and temperature--go into how long a tank will last underwater, a low-capacity tank on a typical 60-foot dive will generally last around 45 minutes.

Standard Capacity

A standard-capacity SCUBA tank holds around 3000 psi. This translates, generally speaking, to about an hour underwater on a 60-foot dive.

High Capacity

A high-capacity SCUBA tank holds between 3300 and 3500 psi, or enough air to last approximately 80 minutes or so at a depth of around 60 feet. Again, how hard you have to work, the temperature of the water, and the depth of the dive can greatly affect these times.

Article Written By William Jackson

William Jackson has written, reported and edited professionally for more than 10 years. His work has been published in newspapers, magazines, scholarly journals, high-level government reports, books and online. He holds a master's degree in humanities from Pennsylvania State University.

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