Background
Recently I had to help a fisher to clear a bay for fyke net fishing. The place was littered with fyke net anchoring stakes that had to be removed before placing a new fyke net was deemed safe. Depth was 15 feet. Visibility varied between 0 and 25 inches. 13 stakes had to be recovered and they were initially located by side scan sonar and then more accurately by ordinary sonar. A buoy was then thrown in as close to the target as possible. No matter how close the buoy anchor weight landed a circular search was still required. One could not see a thing! The stakes had to be located and marked and after that a recovery rope had to be fetched and attached to the stake. Hence, a minimum of two dives per stake were required. I am pretty used to diving in zero viz but a number of resurfacings and new attemps were still required. All of this led to 34 dives to be performed.
The dives
I did do 34 dives to 15 feet in 4 hours. Time submerged was 90 minutes. Water temperature +8C on the surface, +6C on the bottom. I spent 4 hours in water.
The fears
I fear that no decompression algorithms (including the bubble models) have had their parameters statistically adjusted to guarantee such dives to be safe. A realized this a little bit too late having already taken the damage. My computer was happy, my body was not.
The symptoms:
I assume that those larger cavities in the bloodstream that play no role after 3-4 dives got pumped up enough with nitrogen during 34 successive dives to cause symptoms. So perhaps I suffered some nitrogen damage, while not full blown DCS.
The future
My plan for the next time is to replace air with nitrox 40 and limit the submersions to less than 30.
Recommendations and advice welcome!
Recently I had to help a fisher to clear a bay for fyke net fishing. The place was littered with fyke net anchoring stakes that had to be removed before placing a new fyke net was deemed safe. Depth was 15 feet. Visibility varied between 0 and 25 inches. 13 stakes had to be recovered and they were initially located by side scan sonar and then more accurately by ordinary sonar. A buoy was then thrown in as close to the target as possible. No matter how close the buoy anchor weight landed a circular search was still required. One could not see a thing! The stakes had to be located and marked and after that a recovery rope had to be fetched and attached to the stake. Hence, a minimum of two dives per stake were required. I am pretty used to diving in zero viz but a number of resurfacings and new attemps were still required. All of this led to 34 dives to be performed.
The dives
I did do 34 dives to 15 feet in 4 hours. Time submerged was 90 minutes. Water temperature +8C on the surface, +6C on the bottom. I spent 4 hours in water.
The fears
I fear that no decompression algorithms (including the bubble models) have had their parameters statistically adjusted to guarantee such dives to be safe. A realized this a little bit too late having already taken the damage. My computer was happy, my body was not.
The symptoms:
- I felt very exhausted the whole evening. No need to sleep, but physically very very tired.
- Next morning I woke up and felt some itching. It felt like wool against the skin. I have never before had that sensation in the bed in the morning. Two hours later this symptom was gone.
I assume that those larger cavities in the bloodstream that play no role after 3-4 dives got pumped up enough with nitrogen during 34 successive dives to cause symptoms. So perhaps I suffered some nitrogen damage, while not full blown DCS.
The future
My plan for the next time is to replace air with nitrox 40 and limit the submersions to less than 30.
Recommendations and advice welcome!
