I disagree. Deco isn't something to be avoided at all costs, just needs training. I'm taking a PADI AOW through BSAC Sports Diver training tomorrow and will do a simulated mandatory decompression dive with them - its part of our core training..
Diver vs DM Responsibilities
- Thread starter mcohen1021
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
I believe we do too good a job scaring students about the dangers of going into deco, while not devoting enough time to the dangers of rapid ascents and the procedures for unplanned deco.
I went to the Galapagos as part of a large group. I was assigned to room and buddy with the only other single diver in the group. He had DM certification, although he had never worked in that capacity, and it had been years since he had gotten that certification. One day we were diving at maybe 85 feet or so, and he suddenly started a rapid ascenttoward the surface. I saw it happen almost immediately and took off after him, catching him at about 50 feet. I grabbed his fin to stop him. When we got face-to-face and I gave him a "WTF?" gesture, he showed me his computer, a Suunto Vyper, with his eyes wide with terror. I looked at it and saw nothing worth mentioning and repeated the gesture. He resumed his panicked ascent. I caught up with him again, and he once again showed me his computer with that same look of panic. It was counting down a 3-minute safety stop, as would be normal for that depth.
We surfaced after that stop and were picked up by our panga. Each time other divers boarded, he repeated his tale of terror--he had almost gone into deco! When we were at 85 feet, he had looked at his computer and seen he had only 3 minutes of NDL time left. That was why he had started his very dangerous sprint to the surface. He had not looked at his computer during that ascent, so he did not know that when he showed it to me the first time, it was showing something like 45 minutes of NDL. He refused to believe me when I told him that when he ascended, the computer had given him more NDL time. He refused to believe me when I told him that if he had gone into deco, he just had to let the computer guide his decompression--he would not have suffered an agonizing case of DCS and likely death with the boat so far from a chamber.
A couple of years ago, I was conducting a DM course academic session. When I told them that slipping into a little deco was not a big deal and merely required following a correct protocol, they were all amazed. Their idea of going into decompression was similar to that of my dive buddy in the Galapagos. It was to be avoided at all costs.
According to a joint DAN/PADI analysis of dive fatalities, the number one cause of accident-related death in diving was an embolism caused by a rapid, panicked ascent. I wonder how many of those rapid, panicked ascents were caused by a sudden fear of going into deco, as was the case with my buddy in the Galapagos.
I went to the Galapagos as part of a large group. I was assigned to room and buddy with the only other single diver in the group. He had DM certification, although he had never worked in that capacity, and it had been years since he had gotten that certification. One day we were diving at maybe 85 feet or so, and he suddenly started a rapid ascenttoward the surface. I saw it happen almost immediately and took off after him, catching him at about 50 feet. I grabbed his fin to stop him. When we got face-to-face and I gave him a "WTF?" gesture, he showed me his computer, a Suunto Vyper, with his eyes wide with terror. I looked at it and saw nothing worth mentioning and repeated the gesture. He resumed his panicked ascent. I caught up with him again, and he once again showed me his computer with that same look of panic. It was counting down a 3-minute safety stop, as would be normal for that depth.
We surfaced after that stop and were picked up by our panga. Each time other divers boarded, he repeated his tale of terror--he had almost gone into deco! When we were at 85 feet, he had looked at his computer and seen he had only 3 minutes of NDL time left. That was why he had started his very dangerous sprint to the surface. He had not looked at his computer during that ascent, so he did not know that when he showed it to me the first time, it was showing something like 45 minutes of NDL. He refused to believe me when I told him that when he ascended, the computer had given him more NDL time. He refused to believe me when I told him that if he had gone into deco, he just had to let the computer guide his decompression--he would not have suffered an agonizing case of DCS and likely death with the boat so far from a chamber.
A couple of years ago, I was conducting a DM course academic session. When I told them that slipping into a little deco was not a big deal and merely required following a correct protocol, they were all amazed. Their idea of going into decompression was similar to that of my dive buddy in the Galapagos. It was to be avoided at all costs.
According to a joint DAN/PADI analysis of dive fatalities, the number one cause of accident-related death in diving was an embolism caused by a rapid, panicked ascent. I wonder how many of those rapid, panicked ascents were caused by a sudden fear of going into deco, as was the case with my buddy in the Galapagos.
Last edited:
OP
mcohen1021
Contributor
I understand that the tables and dive computers have a margin for error with regards to deco. Otherwise, there would be A LOT more people getting DCS every year. However, the original topic of this thread was not to discuss deco diving or tec diving. It was to discuss NDL recreational diving and the Diver / DM responsibilities from each perspective and the protocol to follow if those established NDL thresholds were compromised.
Seems that my opinion of setting established safety rules and my own interpretation of NDL rules may not be very popular because everyone is gung ho about going on that next dive while maximizing bottom time. But at least if it was my ship, everyone would come home safely.
Happy Diving, Gang
Seems that my opinion of setting established safety rules and my own interpretation of NDL rules may not be very popular because everyone is gung ho about going on that next dive while maximizing bottom time. But at least if it was my ship, everyone would come home safely.
Happy Diving, Gang
gcarter
Contributor
The issue (for me at least) is not your opinion on setting safety / NDL rules, it is your opinion on the power of a DM over an individual diver. If I have hired you, I will not have hired you to tell me what my dive is allowed to look like. If you don't like my plan, turn down the gig. If you insist on your rules, I will not hire you. There is nothing magical about being a DM that makes you right or gives you power over me. Nobody decides my safety except me.
If it is a boat captain's rules, I will either follow them or choose another boat. Again, my choice.
To be clear: as I have previously posted, I am not in the habit of ignoring safety protocols. I am not interested in deco diving. I watch my NDLs and air, and manage them well. I just don't like the arrogance of someone else thinking that they have the right to decide for me without my consent. It doesn't work that way.
OP
mcohen1021
Contributor
Understand your opinion.
This is not me being arrogant or that a DM should be able to ‘show their power’ over a diver. Again, just my .02 cents, safety (not arrogance, power or control) is the #1 concern for both the diver that might have surpassed the NDL and the others on the boat that did not. When the established NDLs are exceeded, DCS does become a [higher] risk both on that dive and subsequent dives
This is not me being arrogant or that a DM should be able to ‘show their power’ over a diver. Again, just my .02 cents, safety (not arrogance, power or control) is the #1 concern for both the diver that might have surpassed the NDL and the others on the boat that did not. When the established NDLs are exceeded, DCS does become a [higher] risk both on that dive and subsequent dives
Your boat, your rules. If a group DM is required I am probably not on your boat anyway.
But if I have two computers and one says I have just hit NDL and the other says I have 15 minutes of NDL what is your interpretation? Am I or am I not in deco on your boat?
OP
mcohen1021
Contributor
@boulderjohn
That is one of the most sensible posts I have seen on this board about decompression since I joined. I was going to quote @Edward3c, but I read yours and I though it worthy of mention.
Edward suffers from the severe handicap of having been taught to believe all dives are decompression dives, some involve compulsory stops, some don't. There is little difference between the two if you have planned the dive properly.
Therefore, Edward, like me gets very confused with the horror it appears to engender on these boards. There is almost a religious zealot reaction, as if you have committed the most heinous sin if you do a dive where a compulsory stop is required.
Thank you John for an enlighten post.
Gareth
Similar threads
