Course Outline

Objective: Perform a simulated controlled emergency swimming ascent (CESA) for a distance of 9 meters/30 feet.

Value: If you should unfortunately find yourself in an out-of-gas situation when your buddy is too far away to lend assistance, you will need to make an emergency ascent to the surface. By practicing ahead of time, you will know that you can reach the surface on one exhaled breath. However, you should remember that this is definitely a last-ditch attempt, and you should never need to attempt this kind of ascent. Simply monitoring your gauges and staying close to your buddy will give you many much safer options should you experience an underwater emergency.

How It’s Done: Performing a CESA can be done in any of the confined water dives after your first one. Your depth must be less than 9–12 meters/30–40 feet.

  1. Simulate taking a final breath from the cylinder.
  2. Elevate the BCD hose to release the expanding gas during ascent. Elevating the hose also protects your head.
  3. Swim diagonally for 9 meters/30 feet while slowly exhaling all the way, keeping an open airway, and emitting a continuous aaah sound.
  4. Do not swim faster than 9 meters/30 feet per minute.
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