Working dives are hard. There's no way around it. Most often, the tasks we carry out are not with surgical precision - they are with a crowbar.
Working divers are they themselves tools of the trade. Much like an ROV that is sent on a dive equipped to carry out a task, the diver is sent on a dive to carry out a task. One thing that an ROV can certainly not do is break a ten year old shackle buried 3 feet into spooge mud in zero visibility. How's that for job security!The brute force required to do this type of grunt work is among the reasons why we will forever need divers working in the ocean. This is among the more superficial reasons, but is indeed a reason.
This type of work illustrates our limitations as well however - that is that we are indeed human and can feel pain. Further, once we're broken, we're hard to fix, and expensive to replace!
I've written about a number of health issues I've faced with such long, repeated, immersions across the full spectrum of human accessible depths - infection, possible CO poisoning, CO2 issues, HPNS, wet breathing (pulmonary stress), severe fungus issues (yum), and the list goes on. Day by day however, there are just a few things that get you almost every time - bumps, bruises, and the bends.
Bumps and bruises comes with using yourself as a tool to carry out that work requiring brute force. In a weightless environment, it is easy to reposition yourself at almost any angle imaginable to apply force, leverage, torque, and so on to a tool or structure. These contortions were allot easier ten years ago, but remain a critical part of the job. It's not uncommon to go home with various bumps and bruises from just plain hard work.
Bends on the other hand is something we do our absolute best to avoid at all costs. The absorption of inert gas into our tissues under pressure, then being released as we ascend causes tissue stress. These downs and ups, or pressurization and depressurization, can wreak havoc even on very hard tissues like bone. While diving is both depth and time dependent due to these inert gas absorption issues, one area we know so very little about is extremely long exposures in very shallow water (low pressure) that is not indicated ona dive table. In fact, dive tables don't even start until 40 feet of depth! What about those first 40 feet?
While I've made some epic dives to almost 500 feet of depth for exploratory purposes, the vast majority of my working dives are in 20 feet of water or less. Many might say 'no big deal'. But the challenge comes with two areas - the exposure at depth can often exceed 6 or 7 hours a day, and can occur for days on end, and second is the frequent ascents and descents often made to do things like grab a tool from the surface, or communicate. I tend to believe that these numerous ups and downs are just as bad for you, if not worse that a single lengthy exposure, even pushing published decompression limits.
While I cannot say for certain that I have been bent, I can say that the effects of nitrogen have been hard felt on several occasions. Fatigue is one sign of decompression sickness (DCS), though could also be a symptom of the bumps and bruises. Severe, almost crippling arthritic pain in my hands could also be a sign of DCS, though could also be attributed to the bumps and bruises, or even crippling cold water.
If and when we take to the sea more permanently, I'll recall these long shallow exposures well, and will do everything possible to mitigate the risks with shallow water DCS. This could come by way of altering breathing gas, or - let's think ahead a bit - perhaps we'll find some means of altering our physiology such that we do not absorb inert gas under pressure, or perhaps we find some new gas that can't be absorbed.
It all may sound like voodoo science right now, but so was nitrox 30 years ago, and rebreathers 20 years ago. In the big picture, we've only just broken the surface in understanding where our limits are in this journey to a new life in the sea.
