SAFE SCUBA DIVING DESCENT

How to Conduct a Safe Scuba Diving Descent

scuba diving descent
Controlled Descent

Controlling the descent rate is an important element when scuba diving; It offers as time to get used to the surrounding, minimizes risks and damages both to us and the environment. Let’s find out how it’s all done.

Why is a controlled descent so important?

Descending slowly and comfortably is pretty simple, but isn’t trivial to new divers.

There are many reasons for learning to descend properly:

  1. Descending fast we risk squeezing our air spaces especially our ears. We must descent slow to allow our air spaces, such as masks and ears, enough time to equalize the changes in pressure.
  2. If close to the bottom when descent starts we can easily damage the environment, by crushing the fragile reef, stepping on creatures and so on.
  3. By descending fast we’re risking ourselves. There are plenty of creatures like Stone fish to Stingrays we don’t want to step on unintentionally.
  4. Stirring up the bottoms composition will decrease visibility.

How to complete a controlled descent:

Remember the acronym S.O.R.T.E.D

SIGNAL– signal everybody that the dive is about to begin

ORIENTATION– look around you above the surface and below, if you are to finish that dive at the same spot, it may be good to know how the exit point looks like. Look bellow you for a clear path to descent, and a quick orientation as to where you’re about to go.

REGULATOR– exchange the snorkel with the regulator.

TIME– start your timing device. Dive starts now. Dive computers will do this automatically.

scuba descent
Don't forget to Equalize every few feet/meter, especially at shallow water

EQUALIZE/ELEVATE– remember to equalize frequently, especially at shallow water, where pressure changes more dramatically. Elevate the Low Pressure Inflator Hose to allow air trapped in the BCD to vent out.

DEFLATE/DESCENT– slowly and gradually deflate your BCD, best way is to deflate it once, exhale and check if you descend or not. If you’re still on the surface, repeat this again until you descent slowly.

Tips for safe and controlled descent:

  1. Descent feet first. It’s easier to deflate your BCD using the LPI hose and it only works when it’s the highest point of your body. That means you need to face up when dumping air through the LPI.
  2. By descending feet first if you release too much air and become negatively buoyant, you can always swim up a bit.
  3. Remember to equalize your dead air spaces; your mask and ears. If you experience problems equalizing, stop your descent, signal your buddy and ascent a few feet/ meter to relieve some of the pressure. Learn more about equalizing here.
  4. It’s important to carry the right amount of weights necessary for your dive. Carrying to much weight can cause rapid descent if to much air is released at once. Find out how to estimate how much weight you need and how to complete a buoyancy check.

2 comments

  1. so just to be clear, if i am weighted correctly using a 80 lb AL tank, i will be negatively buoyant at the start of the dive, therefore I will want to dump air slowly out of the bcd to ensure i dont drop like a rock…. when the tank is near 500 psi, i can expect to be more or less neutrally buoyant thereby ensuring a safer ascent and easier ability to do a safety stop. but…..for the first portion of the dive, i will have to ensure that there is some air in the bcd—esp at depth to keep me off the bottom. is this correct?

  2. Let’s see: The tank does not weight 80 pounds, it holds 80 cubic feet of gas. It is correct that the tank will be slightly heavy at the start of the dive due to the weight of the compressed gas and will be somewhat lighter at the end of the dive when most of the gas is used up, but just by a couple of pounds. A proper weight adjusted diver will float at eye level on the surface with a full tank and a holding a full breath when the BCD is deflated. Therefore to start the dive signal your buddy, check the time, put your regulator in your mouth, deflate the BCD and exhale deeply to start gradually moving downwards. BE SURE THE GAS IS FULLY ON AND THE PRESSURE IS AT 3,000 PSI AND THE REGULATOR TESTED AND BREATHING PROPERLY BEFOREHAND. As you sink, relax breathe comfortably and remember to clear your ears every 6 feet or so. Control your descent! Do this by Keeping your hand on the inflator and add little spurts of gas to adjust for the increase in pressure as you go down. Don’t hit the bottom but add some gas, stop the decent and hover a few feet up in a nice horizontal body position. While you are waiting for the group to assemble, use that time to orient yourself to the surroundings and focus on your breathing until you are at a nice relaxed breathing rate. Then get with your buddy, check the direction of the boat (bow pointing into the current) and check your depth. When you are both ready set your compass lubber line and move towards the current and begin the dive (or follow the group). Turn the dive at about 1,200 pounds PSI and head back to the boat using the compass reciprocal, moving with the current. This will save energy and work and it will cause you to be confident that you have plenty of gas for a comfortable return trip. When you get back to the anchor line, begin a gradual ascent, the slower the better but no faster than your smallest bubbles (OR the speed your computer indicates). When you get to 15 feet hover and do a safety stop for 3 minutes (or more if you have plenty of gas). Remember, in shallow water the gas will last much longer than at depth. Keep an eye on your gas and don’t go below about 500 psi if you can help it. Use that extra gas to inflate your BCD at the surface and signal the boat that you are OK and await pickup with your buddy. If they don’t see you, inflate your surface marker buoy and signal them with it until the captain sees you. If you follow this plan, you will always be comfortable and confident on your dives and enjoy your time underwater. Have fun and good luck!

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