Our plan today was fairly complex but logical: We would take the main line down to the 4th set of double-arrows and do a jump to the right to the Sulphur Falls line. We would go about 200-300 yards until we hit either a "T" or a jump that I remembered, and then take that to a right-angle right turn down to the Wonderland passageway. Brad and I had visited Wonderland two years ago and I remember having seen a "T" in the line there, but we did not go beyond it. Glenn and I hoped to penetrate one, if not both of those directions off the "T".
I would be lead diver today, running reels and determining when to turn on one of several possible scenarios: Out of Reels, Out of Bottom Time, 3rds, Line Ended, Sidemount Territory, etc.
Our dive went off without a hitch. The jump off the 4th set of double arrows is much shorter than it was two or three years ago, and visibility along Sulphur Falls line was excellent. The halocline here was extremely well defined today, almost hypnotizing to watch. The saltwater (lower) layer we were swimming in was still, clear and warmer. The fresh/brackish layer above us had a noteworthy current and lots of debris. I popped up into it several times to check on visibility but the cold-shock was enough to make me want to go back to the salt water. I kept out of the fresh water for three reasons:
- it was an upstream current so I would be fighting it all the way up Sulphur Falls;
- it seemed MUCH colder even though I was wearing two 3-mil wetsuits, and the temperature difference was probably only 2-4 degrees F, it seemed a lot more!
- passageway height was variable and I would have to go up and down through the halocline layer to avoid it, whereas the floor of the cave was pretty consistent.
Sulphur Falls area itself was beautiful to behold. In places where there were ledges just above the halocline, the freshwater rippled in tiny rapids like an inverted brook dancing over pebbles. Our fin-strokes, though optimized to keep from stirring the halocline, left wakes of oily-looking water where visibility went from 50 feet to zero in an instant.
At the turn to Wonderland I found the line was no longer a "T" but hooked the sharp right to Wonderland passage. There was a jump to the left, but I will have to save that one for another day. Almost immediately we descended from 35 feet down to 60 feet into Wonderland. Aaah! Those beautiful stalactites Brad had photographed two years ago were still as I remembered them -- plentiful, but dark and brooding. The "T" was there too, just as I remembered it, so with approval from Glenn I put a cookie on the exit line and went right-wards. The passageway opened up to a glorious large room reminiscent more of caves around Akumal than other parts of Aerolito. Grand stalactite formations covering both walls, but still very dark, almost black.
Then we encountered the first section of broken line. Some repairs (recent?) were notable but there was still a gap where part of the line had broken, the loose section trailing into the canyon. I pulled out my last jump spool and bridged the gap. The line then takes a sharp turn to the left and down deeper, but I also saw a jump here to go straight. Not having another jump spool, the direction was clear. Down we went! Almost immediately I encountered a minor restriction. I squeezed through it quickly, but it gave Glenn several minutes of frustration to get through. I watched him carefully for any signs of panic or needing assistance, but he seemed okay... just stuck. Meanwhile I check my gauge and read "75 feet, 22 minutes remaining no-deco time" though plenty of air time before hitting 3rds. I guess all that practice in minor restrictions at places like Calimba, Blue Abyss and Minotauro paid off -- watching Glenn struggle with what was easy to me made me thankful for all the cave diving and rock climbing experience.
The passageway here changed radically. We were now in a very tight passage only 6-8 feet wide and maybe 4 feet tall. The bottom was covered with a super-fine bright red silt that stirred exceptionally easily. There were stalactite formations here of indesscribable beauty like none I'd ever seen anywhere else on earth. Though the floor and walls were coated with this red dust, the formations were icicles in size, color and appearance. Against the red they virtually reflected green!! And boy, they looked fragile.
I continued on the passage very slowly, taking note of the condition of the line (it was okay) and trying to minimize how much my actions stirred up the silt. Even with my most delicate motions I knew that we were going to lose visibility. Not far later, maybe another 200 feet, the line simply ended at a wall of stalactites, though I could see the cave continue on, though much smaller than a diver could fit. I turned the dive on "End of Line."
And then it happened. Total silt-out. Glenn's turning around followed by my own in that tiny passageway stirred up so much that I lost all visibility. My bright 10 watt HID light made the water glow red but I wouldn't have been able to see the fingers in front of my eyes! Here again, proper cave training paid off. Anticipating the silt-out, I already had my fingers on the permanent line before I lost sight of it. Remembering where it was positioned relative to the cave just before I turned, it was easy to follow the line gently by touch alone for about 20 feet until the silt-out cleared up almost entirely. I exited this beautiful passage reluctantly, admiring all the delicate formations one last time. But the bottom time clock was ticking and I was down to 7 minutes before facing deco obligations.
Back thru the minor restriction (Glenn got thru much faster this time) and then back up to the 60 foot depth. Whew! We retraced back to the "T" at the beginning of Wonderland. After brief discussion, we agreed to try the other direction of the "T" which was leftwards, for a brief time. This quickly became a very tall and relatively narrow passage with formations mostly in a crevice below us, and then suddenly opened up into an E-n-o-r-m-o-u-s room that I never would have suspected in Aerolito!! It could have been 150 feet across, easily. And maybe 30-40 feet from floor to ceiling in some places. In the center of the room the line was tied to a stalagmite and made a sharp jump to the right. I could see a short jump from this point to a line straight ahead. I turned right and continued as it went to the edge of this huge room.
Shortly after reaching another passage from the room, the line was obviously deteriorating with more sections broken down. I turned the dive on "unsafe line" and we unwound our way, back to the huge room, back to Wonderland, back through Sulphur Falls, back down the main line, and out.
Total time in the cave was 86 minutes, with a maximum depth of 78 feet. I used approximately 1550 psi in my double 80 c.f. steel tanks. Not bad for a long dive where most of my time was spent at or below 60 feet m.s.w!!
Footnotes
I'm writing these footnotes a few hours after having written the above. I realise I may have understated the seriousness of a silt-out event. If you read accident analyses on scuba diving and particularly cave diving accidents, silt-outs are a major contributing factor to underwater fatalities. All too often, divers are either unprepared for, or subject to panic when a silt-out occurs. My cave instructor (as I'm sure all reputable cave instructors do) was strict in teaching "Line Awareness" at all times while cave diving.
When I saw the silt-out happening on this dive, it was practically a second-nature reflex to reach for the line, then gently swim through as if I were on one of my "Lights Out" training drills. Absolutely no panic, or even a concern. It wasn't the first time I've been in a silt-out and it certainly won't be the last time. To me it was just a noteworthy event on the dive. However it truly stresses the point that in order to engage in cave (or wreck) diving, you really REALLY need to get proper training for it.
The only concern that we faced on this dive was the bottom time. Although we were within a few minutes of hitting deco, it was all calculated into the plan, including when I would turn at the 70+ foot depth to avoid deco. Glenn pointed out to me after the dive that deco isn't a big deal, but I had to point out to him that we did not factor deco time into our gas planning and thus it was most prudent to avoid it. That of course was the primary concern and really the predominant limit to how much time we spent in the cave this dive.
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