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Failure to maintain buoyancy and trim are the two most common reasons divers inadvertently change their depth during a dive. For instance, with slightly positive trim, a diver will kick their fins to drive towards the surface and will have to adjust repeatedly to maintain depth. Near a silty bottom, sediment will kick up and decrease visibility for anyone. Neutral buoyancy and trim can help with air consumption, decrease energy usage, get you closer to the reef without disturbing it, help you move through wrecks and caves easier, reduce silt, and maintain good visibility.
We asked our Ambassador Jed Grundy for some of his top tips to improving buoyancy and trim. Jed is the Owner of Santa Barbara Aquatics, Santa Barbara’s only full-service dive shop and home to the world-famous Channel Islands.
Body Control
Proper body posture is very important when it comes to maintaining proper trim.
Tips: Keep your back straight (no slouching), push your pelvic bone out to flatten your legs and hips. Keep your head up and look straight out.
Ensure Proper Weighting
Many divers today dive overweight. This can complicate things when it comes to proper buoyancy. Over-weighted divers constantly need to adjust the amount of air in their BCD, which makes it harder to stay consistently stable.
Weight Distribution
When it comes to diving Sidemount or Backmount, weight distribution is critical. For a Sidemount diver, moving weight up or down the spine weight can fix any heads-up or heads-down positions. Backmount divers can move weights to trim pockets or main pockets to fix the same issue.
Another important factor of weight distribution is tank placement. Plenty of divers have tanks too high or too low, and this will shift their center of gravity causing a heads-up or heads-down position.
BCD Control
Most new divers don’t fully understand just how many BCDs people actually dive with. For instance, wetsuit divers have two (BCDs/Lungs) and drysuit divers use three (BCD/Drysuit/Lungs). It’s a gentle game of understanding how these two or three can work together to create good balance.
It’s also important to understand the lag time between adding or removing air from your BCD compared with the lag time of your lungs. Divers need to slow down and be more patient before they decide they need to add or remove air from either system. This means taking a few full breaths and letting things settle before taking more action.
Equipment Choice
Equipment plays a factor in weighting and trim. Fins that are too heavy or too light for a specific diver will change how they trim in the water. Some dive boots are positively or negatively buoyant and can play a factor.
Proper Training
Divers can work on these points on their own, but would benefit more by taking a class from a professional instructor who can walk them through each of these points and demonstrate how to properly balance their system and help create great trim.
Bonus Tips
Consider Lighter Fins — The Hollis F-2 fins are great positively buoyant fins.
Move Your Wing Lower — Shift the wing so it is as low as possible on your hips. Try different mounting holes on the wing. Try lengthening the shoulder straps and shortening the crotch strap to shift buoyancy lower.
Dry Suit — If you wear a drysuit, like the DX-300X, allow more air to drift towards your feet.
Thicker Neoprene — Use a thicker neoprene suit such as the Hollis Neotek Semi Dry.
