Partial Map of Sac Aktun

Today we visited Gran Cenote in the Sac Acktun system. This became the largest submerged system in the world when it was connected to Nohoch Na Chich by Steve, before being overtaken by Ox Bel Ha, further to the south, mid of this year, when previously unsurveyed passages were added to this system. They are roughly of the same size. About 160km. Put together, you could fit the whole A1 freeway from Porto to Lisbon, inside of these systems. That's how big they are.

The Gran Cenote is one of these pools where you find swimmers and snorkelers, although today it was not busy. It's a nice, tranquil place.

A split shot of the Gran Cenote water basin

First we dove Paso del Lagarto and Much's Maze. All wide open spaces, very white, pristine, monumental. Average depth 12 meters. Navigation here is complex. Several jumps, some 20 or 30 meters apart. If you don't know the cave it can be tricky to find the lines.

In December of 2004 there was a double fatility in here. 9 divers, split into two groups but sharing markers and lines, dove from Cenote Calimba in the direction of Cenote Box Chen. The group of 4 divers took a wrong direction decision on the return as pointed in the map above. They should have followed the red arrow but took the yellow arrow direction instead. They came all the way down the Paso del Lagarto line. At the end of the line they tried to find the Gran Cenote line. It's a long jump, and they couldn't find it. Gran Cenote or Cenote Hotul were just a few minutes away.

They tried to go back to Cenote Calimba. The other group had already removed the markers and lines having thought that the first group had already exited. 2 divers made it out with just 700 psi total left in their tanks. The other two run out of gas and their bodies were later recovered a hundred meters from the exit.

I took the camera on the first dive. The second dive, towards the Caverna de los Comillos and the restriction of La Boca, had even more complex navigation, so I decided to leave the camera behind. We had four jumps, first turning left into the shortcut to cenote Ho-tul, then back to the main line. Next we had to gap the cenote, and finally we had to jump from the Cuzan-Nah circuit to the Cavernas de los Colmillos line. It was a great dive. First time in this system but I feel like returning.

Some pictures from the first dive follow.

Steve entering the Paso del Lagarto

White decorations and walls

Some more pristine spleothems

On return, Gran Cenote becomes slowly visible