Hawaii Big Island Diving

Every dive shop, dive boat, and scuba diver uses scuba tanks. While we all have used the standard Aluminum 80 cubic foot tank, we have seen a great many different size and shapes in other scuba tanks. Each of the “different” scuba tanks have a unique advantage/disadvantage, use, and cost. How can you choose the right scuba tank?

Let’s walk through the basic considerations to choose the perfect tank:

• Budget. The reason the Aluminum 80 tank is everywhere is because it is cheap. But so are the Aluminum 50, 63, and 100 cubic foot tanks, so why is the 80 cubic foot the most popular? It is simply because it is the first Aluminum size (actually the second size), but the first 72 cubic foot Aluminum tanks were rounded bottoms and a bit taller.
• Physical Size of the Scuba tank. It is generally the length of the tank and not the diameter that will bother most scuba divers. Carrying the tank without dragging it across the boat dock is a sign that either you cannot carry the weight or your arms are not long enough. If strength is not the problem than maybe the tank is too long. Or if you keep hitting your head on the tank valve and the bottom of the tank is bouncing off of your butt at the same time, than the tank is too long. The two main tank manufacturers (Catalina and Luxfer) both make an Aluminum 80 tank that is 3 inches shorter than the standard tank. They do this by increasing the diameter of this new tank, but it is a little heaver. The Aluminum 63 cubic foot tank is 21.5 inches long. Some of the high pressure steel tanks are only 20 inches in length.
• The Air Capacity of the Scuba tank. If your air consumption is markedly less than your dive buddy’s, why carry the extra air back to the boat? If I am diving with students; than a smaller 50 cubic foot is perfect. If I am diving with my wife than I use my 100 cubic foot tank, while she uses the 50 cubic foot tank. Choose the capacity that best matches your air consumption, dive objective and appropriate safety considerations.
• Weight and Buoyancy considerations. The major disadvantage of Aluminum Scuba tanks is they tend to become positively buoyant at the end of each dive. The Aluminum 80 cubic foot tank can be up to 5 pounds of positive buoyancy at 500 psi. Both Luxfer and Catalina now make a newer neutral buoyancy Aluminum 80 tank to solve this problem. Of course you might want to consider a steel tank. These steel scuba tanks are approximately 20 inches in length and do not have the positive buoyancy problems that Aluminum tanks experience. The down side of the steel scuba tanks (3500 psi) is that they operate at higher pressures and not all dive operations can fill them. The steel material tends to rust if any water or humidity enters the interior of the tank. Lastly the price of the steel tanks can be 2 or 3 times the prices of the Aluminum tank.

We all know being able to clear your ears while scuba diving is very important. After all, if your ears don’t clear you’ll have to abort the dive. So how do you clear your ears?

The most common method is called the Valsalva maneuver. In this technique, you pinch your nostrils closed and gently blow through your nose.

If you are having problems, try these steps to help you descend safely:

• Start Before You Go Below the Water

If you are using the Valsalva maneuver, gently blow through your nose while you are waiting to start your descent. This “pre-pressurizes” the ear and makes equalization easier upon descent. Start this before you even go under the water.

• Equalize Early and Often

You’ve heard this in your scuba diving class. Begin equalizing as soon as your head goes underwater and continue equalizing every few feet. This is probably the most important step to descending without ear problems. If you are having problems clearing one ear, tilt your head – with the blocked ear toward the surface.

• Descend Feet First

Your Eustchian tube is affected if you descend with your head first and it makes it harder to equalize your ears.

• Ascend if You Have Problems

If your ears are not clearing properly, ascend a few feet to reduce the pressure. Try clearing them again. If it still doesn’t work, ascend a few more feet and try again. Rinse and repeat until you have cleared your ears successfully.

• Do Not Force It

If you have tried ascending and it is not working, abort the dive. If you force yourself down, you can cause permanent ear injury. In this same vein, if you are using the Valsalva method, do not blow forcefully. It should be a gentle blow. A forceful blow can also cause ear injury. It’s better to forego a dive than have ear problems for the rest of your life.

• Do Not Dive With a Cold

Another mantra you probably heard in your scuba class. Congestion can make equalization difficult. And even if you are able to ascend, you run the risk of having problems during ascent, a condition called “reverse squeeze.” This can also be caused by medications wearing off during the dive. If you do take medicine, just be aware of the risks.

Follow these steps and you should be well on your way to having nice clear ears. Take it easy, take it slow and have a safe, comfortable dive.

Have a great dive! Dianne from www.scuba-diving-smiles.com