Silted out in a wreck? How to avoid this by using proper buoyancy and propulsion techniques


Photo Credit Aldo Ferrucci

Imagine you are diving your favorite wreck and you notice an opening you haven’t seen before…  The opening is plenty big for you to get in and the room beyond seems large and easy to navigate; so you swim in planning on making a quick tour and coming right back out.  Once you’re inside you only swim around for a couple of minutes, but when you turn around to head back out, all you can see is blackness.  Your exit to open water and the surface is now hidden somewhere behind a wall of thick silt.  Your dive light only penetrates a few inches into the muck, and you can only see your hand in front of your face once it is pressed against the glass of your mask.  As the seriousness of the situation sets in, so does panic.

You never thought it could happen to you; the entrance was huge and you only went in a little ways, but now you’re trapped in complete darkness with no idea which way is out.  This situation is all too common, and sometimes ends in tragedy.  There are many dangers associated with diving into an overhead environment.  Creating a slit-out situation where you are unable to find the exit is on the very top of that list.  This can be a very hazardous situation, but can be avoided with proper propulsion techniques, buoyancy control, and trim.

Mastering your buoyancy control is your first step.  This doesn’t mean your buoyancy is good, it means you have 100% control of your position in the water column.  It’s important to work on this with an instructor, and the SDI Advanced Buoyancy Course is a great place to start.  You will learn about proper weighting and master fine tuning your buoyancy with breath control, and you will begin to learn about proper body position and trim. This is the foundation that all of your advanced diving skills are built on.

Once your buoyancy control is dialed in, you can really start working on your trim and swimming techniques.  The TDI Intro To Tech course is a great way to perfect your trim and start working on advanced non-silting kicks such as: Frog kick, modified flutter kick, back kick, and helicopter turns.  It all starts with your trim.  If you are not trimmed out properly, it doesn’t matter how you kick, you’re going to create a messy and dangerous situation in an overhead environment.  Once you are properly trimmed out and have a handle on the various advanced kicks, you can move forward and start training for the overhead environment.

At the beginning of your TDI Advanced Wreck or Cavern course, your instructor will make sure you have perfected the non-silting kicks before brining you into the overhead environment.  This is essential because these kicks create thrust from your fins that can be controlled and directed as you wish, avoiding stirring up the silty bottom and creating a blackout.  Throughout your course, these kicks will become second nature and you will find yourself maneuvering in the water with complete control and efficiency.  This combined with the proper guideline procedures and gas management techniques you will learn in these courses will help mitigate many of the risks involved with diving in an overhead environment.  To find an instructor near you, visit

For more information on TDI courses offered, visit

Contact SDI TDI and ERDI
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Tel: 888.778.9073 | 207.729.4201

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