Let's use our brains and think about it for a minute rather than spouting some general PADI or SSI standard. The captain gave the diver in question a rental tank of 30% and either topped off his other tank with Nitrox - giving a mix of perhaps 25-26% - or drained and refilled his tank with 30% and told him to dive both as if he was on air.
The important thing here is that he did not also give him a shovel as he clearly would have needed one to exceed the MOD of either gas as the boat captain in question new the depths where he was taking the divers and both dives would have been well above the 120' MOD at a 1.4 PPO2. NC does not have wall dives, at least there, so the presence of a flat bottom with a hard sand depth limit makes a difference. The same thing would not be safe on a wall dive, but in this case the MOD was clearly not a safety issue that day or on that trip.
Also, even had they been able to dive to a depth allowing a MOD of 1.4 for the mix used for the entire time on both dives, the single dive CNS limit is 150 minutes and the 24 hour limit is 180 minutes and the maximum time on those would be around 40-45 minutes max from a gas perspective - well within both the single dive limit and perhaps 50% of the CNS clock.
Now look at it in light of the entire situation... The capatain had a boat load of divers who were all on the bottom with 30% in a situation where they are all pushing NDL's. The diver in question and his sig other, were obviously fairly new divers. It does not take much to imagine a scenario where they enjoy NC diving at its best, get distracted and just come up when everyone else starts coming up - but bent like pretzles as they were, unlike everyone else, on air.
So you can look at it from two points of view:
1) A dogmatic, authoritarian point of view where PADI, SSI, etc says "though shalt not dive nitrox without at least our on-line cert" (where God himself only knows who actually helped the student with the parts that almost require math), or,
2) A much more pragmatic and intelligent cost/benefit analysis where the captain actually thinks about the welfare of the diver and considers the risks of diving nitrox (zero in this case for the reasons discussed above) versus the very real risk of the reasonably new diver screwing up and getting bent on air while in the water with a boat load of nitrox.
From that perspective what the captain did was exactly the right thing to do - he gave nitrox fills to ensure as large an NDL as possible and instructed the diver to just dive it like he was diving air - something he knew how to do - adding a large margin of safety if the diver actually monitored his bottom time and still ensuring he was not at an NDL disadvantage compared to other divers if he did not. When you further consider the diver also also had 117's (enough gas to get you in serious deco trouble on air in NC) the captain's decision makes perfect sense.
And essentially "screw PADI" is the right decision for a boat captain to make in this type of situation as PADI is not the controlling legal authority. PADI rules and stadnards will not mean squat compared to the coast guard legal laws and regulations the captain is held accountable to. He is the person responsible for everything that occurs on board and if the diver got bent or died, the coast guard investigators looking into the accident would have at least questioned why he let the diver dive on air in the first place, when there was no real risk of diving nitrox in this situation and given that nitrox is the common gas in NC wreck diving in the 80-120ft range. It is common for laws and standards to come in conflict and when those ethical conflicts between standards occurs an intelligent and well considered solution is required - which is exactly what he did in this case. More importantly in this case, his responsibilities as a boat captain clearly over shadowed his responsibilies as an "everyone can be one in about 2 weeks" PADI or SSI instructor.
So from a ethical perspective based on science, thinking and experience rather than just dogma, one that looks at all the risks, benefits and probable outcomes, the captain did exactly the right thing which is one of the reason he is one of my favorite boat captains. Given that actuaries look at probability and risk and have similar decision making processes, I am sure they'd be just fine with his decisions that day. Let's not miss the more important point that it is well within the realm of probability that he kept a diver from getting bent that day and the diver in question needs to recognize that.
Then there is personal responsibility. The divers in question did not have to dive. The captain did not make them walk the plank and force them to dive. Obviously, they were not worried about it at the time (nor did they need to be) and equally obviously they both survived - but that issue was never in doubt was it?
Now, the captain could have just said "no" and not let him dive at all without a nitrox cert, but that would have screwed the diver with hotel, travel expenses, wasted weekend, etc and there was no need for him to impose that on the diver when a simple and safe resoultion to the problem was available. In fact if he had, many of the people on SB would all be bashing the boat captain for doing that, blissfully ignoring the significant risk that the diver in question may have gotten himself bent if he had used air, and blissfuly ignorant of the captain's larger responsibility to ensure safe conduct of the trip.
If, as a professional you want to bash another professional, get your **** together and make sure your arguments and accusations actually make sense before you start questioning their judgement or slandering them.
----
Stay Thirsty - welcome to Scubaboard!
Glad to have you and I hope you stay around for more than just this issue. Just be advised that in addition to lots of good advice, there is all kinds of bad or poorly thought out information out there - both on and off the board.
Last edited:
