Second Optima CM dive after certification; 14 days since the last dive.
Preparation: Conducted leak-down tests of MAVs and regulators. Shorten leashes on bottom of AL 40s and adjusted bungee retainer system on Nomad LS. Removed 4 pounds of lead from the spine of BC and temporarily put/clipped 2 pounds back. Replaced both DiveCAN batteries.
Dive: Still heavy at beginning of dive so removed 2 lbs. lead. Two pounds remaining. Manageable but still feels heavy. Switched PPO2 setpoint at 70 ft to 1.2 while descending, anticipated PPO2 spike and mitigated by stopping. My second descent back to 98 ft was slower with less spike as expected. Removed DSV, several times, to practice clearing loop. Elevated DSV and shook valve. Some bubbles emitted, but no significant water entered the loop. This increased my confidence in the system. Flew manually. Practiced holding 15-foot depth without visual reference, bailing out, and operating all valves and vents. Was feeling cocky when all of a sudden, I simultaneously needed to check my ascent, clear my ears, and add volume to the loop. I realize that I had turned off the ADV and it was a humbling 10 seconds, that felt like two minutes, prioritizing and accomplishing these tasks. Was chilled after 70 minutes in 72° water in 3mm WS. I made numerous depth changes in this training dive and noticed I frequently vented the loop. I turned off the ADV to see if it was activating on its own. I found no evidence of this. It is stiff enough that I was able to activate it only through a conscious and forceful inhalation.
To do: Need to use a printed checklist. NOTE** I Discovered a problem, overlooked in pre-check, during surface pre-breath. Did not correctly route DiveCAN wire. Need practice gearing up. Muscle memory to find controls by feel greatly improved but still needs work. Will use removable 2lb. weight to fine-tune buoyancy. Make HUD more visible in mask. Currently, HUD cannot be adjusted to remain (clearly) in my field of view. Similarly, O2 pressure gauge is not as obvious to read as I would like; I will readjust. AL 40 cylinders still need to be positioned to stay parallel to my body during the dive. Fixes may be steel 50s and mask with more downward vision than my present one, as my instructor recommended. Steel cylinders would be appropriate for a dry suit. I need to ensure that the low-pressure hose on bailout system can be plugged into MAV or BC. I will test automatic setpoint switching on the next dive. Recalibrate Petrel 2 compass because of battery change.
Bottom line: The dive familiarized me with control locations and functions, and proper weighting. I am more familiar with how the 02 system functions at depth and after practicing most of the certification tasks I have become very confident in the system. I’m now ready to dive in saltwater or incorporate a dry suit with the rebreather.
Preparation: Conducted leak-down tests of MAVs and regulators. Shorten leashes on bottom of AL 40s and adjusted bungee retainer system on Nomad LS. Removed 4 pounds of lead from the spine of BC and temporarily put/clipped 2 pounds back. Replaced both DiveCAN batteries.
Dive: Still heavy at beginning of dive so removed 2 lbs. lead. Two pounds remaining. Manageable but still feels heavy. Switched PPO2 setpoint at 70 ft to 1.2 while descending, anticipated PPO2 spike and mitigated by stopping. My second descent back to 98 ft was slower with less spike as expected. Removed DSV, several times, to practice clearing loop. Elevated DSV and shook valve. Some bubbles emitted, but no significant water entered the loop. This increased my confidence in the system. Flew manually. Practiced holding 15-foot depth without visual reference, bailing out, and operating all valves and vents. Was feeling cocky when all of a sudden, I simultaneously needed to check my ascent, clear my ears, and add volume to the loop. I realize that I had turned off the ADV and it was a humbling 10 seconds, that felt like two minutes, prioritizing and accomplishing these tasks. Was chilled after 70 minutes in 72° water in 3mm WS. I made numerous depth changes in this training dive and noticed I frequently vented the loop. I turned off the ADV to see if it was activating on its own. I found no evidence of this. It is stiff enough that I was able to activate it only through a conscious and forceful inhalation.
To do: Need to use a printed checklist. NOTE** I Discovered a problem, overlooked in pre-check, during surface pre-breath. Did not correctly route DiveCAN wire. Need practice gearing up. Muscle memory to find controls by feel greatly improved but still needs work. Will use removable 2lb. weight to fine-tune buoyancy. Make HUD more visible in mask. Currently, HUD cannot be adjusted to remain (clearly) in my field of view. Similarly, O2 pressure gauge is not as obvious to read as I would like; I will readjust. AL 40 cylinders still need to be positioned to stay parallel to my body during the dive. Fixes may be steel 50s and mask with more downward vision than my present one, as my instructor recommended. Steel cylinders would be appropriate for a dry suit. I need to ensure that the low-pressure hose on bailout system can be plugged into MAV or BC. I will test automatic setpoint switching on the next dive. Recalibrate Petrel 2 compass because of battery change.
Bottom line: The dive familiarized me with control locations and functions, and proper weighting. I am more familiar with how the 02 system functions at depth and after practicing most of the certification tasks I have become very confident in the system. I’m now ready to dive in saltwater or incorporate a dry suit with the rebreather.
