This past week I made a dive that I hadn’t made in some time – 60 [feet] for 60 [minutes]. This is one of those marks within diving space that is well-recognized given the US Navy dive table’s no decompression limit at 60 feet…you guessed it – 60 minutes.
The depth isn’t a challenge, even for the modestly trained sport diver. However, the challenge is that the time at depth places air consumption right on the edge of the dive being capable of being conducted with a single cylinder. At that edge also lies the potential to enter required decompression.
Knowing all of this, and considering the planned dive was anticipated as an arduous one, I carried two cylinders. Again, not too out of the ordinary, though I elected to dive them in a sidemount configuration – this is gaining popularity within the sport diving community since having been established as the norm within cave diving. In my case, this was an inshore working dive, and I had been wanting to experiment with sidemount configurations during these working dives. In general, I think it worked well for a variety of reasons, and I will elaborate on this in future posts.
Now the key in the task loading and hard work was to pay close attention to gas management with the two independent cylinders. I rigged these up with a ball valve on the LP side of the supply which allowed me to stay on a single second stage throughout the dive. I would switch cylinders each 1/3rd via the ball valve, typical of standard sidemount practices. The dive ended up being more like 65 feet deep, and I pushed my bottom time right to 60 minutes to get the job done. As the Navy has done us well, my square profile matched up nicely to the Navy tables, and my computer put me about 5 minutes into required decompression.
So, a nice long one [considering the environment and nature of the dives], and it was very interesting to push through the 60 for 60 threshold which was made possible with the adoption of a little progressive thinking on equipment configuration and applying it to a unique problem. Just a few years ago, for our inshore dive crew, this task would have been split up and tackled by two divers, each making a 30 minute dive on a single tank. I know this sounds archaic within the rec world, but carrying innovation over to the day-to-day working world takes time…all change takes time.
I often wonder what the new 60 for 60 will be. Thinking big and bold, it may be 500 [feet] for 5 [hour runtime]. That profile is a big one, but is right about where today’s rebreather technology gets pushed. It is truly amazing that within a half a century or so, throwing 60 pounds on our back has evolved human capability from 60/60 to 500/5. What could ever come next?!?
Exciting times in this aquatic life, per usual. As much as we think about the experience, the observations, the marine life, and so on, it is important to not overlook how human intervention traverses decompression within the void of ocean space. There are vectors there that are prime for pickin’!