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Instructor Clinic: Buoyancy and How to Finely Tune It

Don’t be ‘that’ diver. Don’t be the diver who has all their own gear, 20 dives since the 90’s and thinks they don’t qualify to take advice from a 25 year old dive instructor about suggested weights and buoyancy techniques. If I had a dollar for every over-weighted, over exerting, non-streamlined ‘advanced’ customer who particularly likes to rake the ocean floor with their brand new Twin Jets I’d be a very rich woman with the means to pay for various reef restoration projects all along the northern hemisphere.  It could be YOU that I’m talking about.

From one diver to another, from a lover of the ocean and someone who wants to preserve its beauty especially when scuba diving in Cabo San Lucas or diving in Cabo Pulmo, I implore you to really think about your buoyancy skills and be honest about whether you could refresh your skills before that all important once-in-a-lifetime diving vacation. If your buoyancy is good you will; breathe easier, move more efficiently in the water, avoid rapid ascents into on-coming boat traffic, you will conserve your air, get closer to the aquatic life and, more importantly, you won’t kill any. Coral reefs are declining at an incredible rate. Please don’t be a part of it.


Theory behind It

As a reminder: If an object is negatively buoyant it sinks and if an object is positively buoyant it floats. You, as a diver, need to achieve neutral buoyancy meaning that when you are in the water you neither sink nor float. This is a skill you are taught at the Open Water Level with the skills such as the ‘Hover’ or ‘Neutral Buoyancy’.  “But I prefer to go over-weighted…” Why? If I carry just an extra 2lbs of weight in case my diver needs it I spend more air adjusting my BCD, my consumption drops ever so slightly and I can feel more of the drag. Perfect weighting is the key to neutral buoyancy.

Neutral Buoyancy – How it’s Done

At the Surface:

  1. Enter the water with you best guess weights on (ask you instructor/DM if you’re not sure as this changes depending on exposure suit and water salinity among other variables).
  2. On the surface with your mouth piece in and legs completely still begin to empty the BCD completely of air.
  3. Once you head goes under and all the air is out of your BCD hold a breath on the surface. This extra lung filled with air should allow you to hover at eye level without any need to kick your feet.
  4. Then, make a nice long gentle exhale while still keeping your feet still and see if you descend slowly.
  5. Going down too fast? Take a weight off. Not going down at all? Add a small amount and try again.
  6. Make sure you are balanced. The weights on a belt should be on even sides. Weights in integrated systems benefit from using trim pockets as well as quick release pockets.

Throughout the dive:

  1. Respect the reef: Descend slowly without touching the bottom.
  2. Diving isn’t swimming. Professionals merely hover and frog kick occasionally to move along. If you still sink down when you are completely still and breathing normally then just keep adding a small amount of air to your bcd until you neither sink nor float and then remove a weight on your next dive.
  3. Buttons and Valves: your best friends. Don’t be scared of your inflate button! Adjust for different depths: in particular when you’re deepest you need to add more than near the surface. Air expands on ascent so watch your depth gauge often so you can predict this. Remember your wetsuit will also become more buoyant on ascent. You may find yourself on the surface if you don’t correct your body position and dump air with the air releasing from the highest point in your BCD towards the sky. Remember you have 3 different air dump points in most rental types, try them all out! Sometimes it is much easier to dump air from the right shoulder valve than from the deflate button in your left hand.
  4. Even your tank affects your buoyancy. You tank will get lighter as you use more air towards the end of a dive. Did you know a full Aluminium tank sinks but an empty one floats?


So if you’ve been out of the water for a while or if you know you will be the first to run out of air in your group (6ft 5” guys are excused!) ask your instructor here at Cabo Trek, Cabo San Lucas for a buoyancy course. Not just for a ‘refresher’. Buoyancy courses are only a few dollars more than a 2 tank dive with refresher and sometimes it’s a good way to get your own private instructor for the course dives. Moreover it is your responsibility as a visitor of the underwater realm to have good buoyancy skills so that there is no need at all to touch the reef; please protect it from your Twin Jets so that everyone will be able to enjoy it for a long time to come.


Cabo Trek also offers:

By PADI IDC Staff Instructor Laura Tyrrell

Contact us for more information or call us TOLL FREE: 1 844 851 9842

Philipp Moser

Scuba in Cabo

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