YAXCHEN CAVE EXPLORATION DIVE LOG AND JOURNAL - Tulum, Mexico YAXCHEN CAVE EXPLORATION DIVE LOG AND JOURNAL 

Exploration has been underway at Yaxchen since February 1997. This log, started in April of 1998, will serve as a record of all science and exploration dives for the project. Equipment: 104 and 95 cubic foot backmounted steel tanks will be used for all exploration dives upstream. 80 c.f. stage bottles, Oceanic Mako and/or Tekna DV-3X scooters will be used for extended range dives.
 

4/16/98 Exploration dive, Kay & Gary.
51ft/167min, 1,530 ft.of line installed.
This dive, to determine if there was another passage out of the NW side of cenote Largo, was planned because of an indication on the aerial photo.  In the northern 1/3rd of the surface pool an indent to the NW led to a steep debris slope and large cave opening.  Halocline at 34ft with white sulfurous cloud layer near the opening could be bacterial in nature if it proves to be similar to the Crystal beach cave system in Florida (see Michael Garman's NACD project).  This tunnel paralleled the main line with little or no flow and came out @150ft below Izod 2 cenote.  The line was named Beefcake.  Also the 4000 line was created branching off to the WSW from this point.  A promising lead to the south in a decorated dome room remains to be checked. This area is close to the western end of the 4000 line.

4/18/98 Exploration dive, Kay and Gary
54ft/211min, 1164ft of line installed.
Two lines were installed on this dive.  The Westworld line and the Red Conch line.  The Westworld line is an alternate path toward the dome room near the western end of the 4000 line.  The Red Conch line is an attempt to go SW out of this dome room.  The only passage found went to the SE and could be looped back into the Beefcake line on a later dive.  A halocline at 50ft was noticed.  This is in contrast to the halocline at 34ft in the nearby Beefcake line.  Floor sediments in RC are red with some conch shells scattered on the floor early on.

4/20/98 Exploration dive, Kay and Gary
47ft/152min, 1087ft of line installed.
Two lines were installed on this dive.  The Grim line and the Diversion line.  The Grim line is an extension of the Fishbone Alley line.  The area is smallish with fine silt dunes and smoky water.  The line ends in a small room w/o continuation.  The Diversion line starts near the turn in the Tarpon 1 cenote and defines passage just north of Tarpon 1.  Passage may continue but is sidemount.  Scooter battery low warning light, due to using old batteries, necessitated a tow out from @4000ft penetration.  The team exited with plenty of air; 1600psi in doubles, 2200psi in stage tank.

4/22/98  Team member Bob Hemm and friend arrive for a brief visit to video additional footage to be used in the presentation "Underground Rivers of the Yucatan".  Sam Meacham videos scootering in Car Wash and some surveying sequences in Yaxchen.  Biology in the downstream at the Chupa 1, Chupa 2 line intersection was also videoed by Sam including, sponges, tube worms, small shrimp and a tarpon.

4/29/98 Set up dive to L shaped cenote.  Gary and Kay
46ft/82min, One 80 c.f. cylinder was placed in preparation for a double scooter, triple stage exploration dive on May 1 close to the end of the upstream line.  Rather than trying for the final 2 cenotes in the chain we may look to the NE just beyond Gemini 1 cenote in order to investigate the surface features seen in the aerial photo.  Scooters will be dropped at a maximum of 30 minutes burn time on the way in.  This should leave us a 1,930ft swim to the exploration area after the second scooter drop at @7,500ft penetration.

5/1/98 Exploration dive, Kay and Gary
47ft/333min, 1324.5ft of line installed.
This was the first triple stage, double scooter dive for the long-range upstream exploration.  One line was installed in order to investigate a large tunnel heading north off the main line at station YXML99.  This line was named the Dragon line and connects a small cenote, which can be seen in the aerial photo.  It then continues NE to a tannic dome/ tunnel that runs east west.  Tunnel continues south at the current end of this line but was not explored due to air limitations.  Perhaps the key passage to the elusive NE area lies closer to Gemini 1 cenote or farther beyond.  Also a significant amount of flow has been noted coming from the SW in Gemini 1 cenote and the Luna cenote just downstream from it.  This flow should be investigated.  
 A clean-up/ set-up dive is planned for 5/3/98 with Dan Lins having the dual purpose of familiarizing him with the area.  Both Kay and I realize that an underwater rescue, should we have an extreme problem of some kind beyond the 10,000ft mark, would most likely be ineffective.  The amount of equipment and energy required just to get there would negate the rescuers' ability to help us.  Then there is the task of finding us.  For this reason we have decided that our best plan would be to make preparations to walk out if necessary.  The cenotes are surrounded by jungle rather than mangrove at that point therefore it should be possible to hike with compass NNE to the trail marking the boundary of the Tulum and Pino Suarez ejidos.  This trail goes east out to the beach road.  We will plan to walk out with team member Sam Meacham to the Esmeralda cenote(s) area to get familiar with the terrain.  I may also make a waterproof housing for the GPS unit, extra batteries and cellular telephone.  The GPS can be pre-programmed with guidance information for just such an emergency.

5/3/98 Clean-up/ set-up dive, Gary and Dan Lins.
40ft/104min
This dive was to place fresh stage tanks at the first drop point in the L shaped cenote.  Makos were run at a slower speed and therefore only showed a green light indicator for the duration of the dive.  Dan enjoyed both the dive and the cave.  I have noticed a numbing effect on my facial skin the last several times I passed through the cloud layers between the Tarpon 2 and L shaped cenote.  Dan said he noticed the same thing.  I am really beginning to wonder what these strange white cloud layers consist of.  They do not tarnish silver or brass the way hydrogen sulfide clouds do.  We will take samples soon for testing by our biologist Samantha Smith.

5/5/98 Exploration dive, Gary.
32ft/107minutes, 821ft of line installed.
This dive done with sidemount gear in a weak siphon under the entry area. The line goes NE toward Chupa 1 line in the downstream section of the cave. Flow was lost @ 200ft before the end of the line.  Two or three major restrictions were passed in mung silt that settled out by exit time. This line could possibly be connected with Chupa 1 by trying a NW or N lead before the flow is lost along the line.  The area is small and quite silty.

5/9/98 Hike out to Esmeralda cenote with Sam Meacham and Bil Phillips.  The trail starts at the hut for the ejido Pino Suarez located on the west side of the beach road just below Osho Oasis south of Tulum.  The trailhead is located at N 20 10.078 - W087 27.093. The walk is roughly 1.25hrs and 4.9k heading first west and then south.  Our area is yet another 2.4 kilometers south of the Esmeralda cenote with no known trail.  An emergency exit for us through the jungle would be very difficult and exhausting even with GPS, compass, water and good shoes. 

5/11/98 Exploration dive, Gary and Kay.
73ft/336minutes, 1417ft of line installed.
This dive with double scooter, triple stage was an attempt to look for passage going toward the final two large cenotes in the chain, which can be seen on the aerial photo.  Also a line named Gemini 2 was laid to the second cenote of a pair shown in the aerial photo at @9500ft penetration upstream. The second line, now named Tunnel Vision line descends into a 70ft deep canyon passage which still continues.  Twenty minutes of deco were eliminated during transit on exit.  Also flow was seen coming from the SW and may lead to another major part of the cave on that general heading.  This dive was rather exhausting despite re-hydration u/w.  We will use Nitrox the next time we go to push the new Tunnel Vision line at the 70ft level.  It will be necessary to add another stage bottle and scooter soon. This will require a double set-up dive with one stage at the "night club" (second scooter drop point), and a fresh scooter and stage at the first drop point.

5/15/98 Clean up/ set up dive, Gary.
40ft/78minutes
This was a short dive for the sole purpose of putting fresh stage tanks into the L shaped cenote for an upstream push on the 17th.  Having given these unusual fish in the surface pool a closer look and then consulting the Audubon Society Field Guide to North American Fishes I am convinced we have some new species in Yaxchen.  Also I now believe that the numbing effect I thought I noticed from the cloud layers between Tarpon 2 and the L shaped cenote was just a temperature shift.

5/17/98 Exploration dive, Gary and Kay.
51ft/329minutes, 1942.5ft of line installed.
Double scooter, triple stage.
This dive was planned to continue the Tunnel Vision line to the SW from station YXTV4, hopefully w/o going deep.  This new line is named Rio Grand. Kay laid the line and I installed the line wraps and surveyed.  Huge tunnel meandered first SW and then west and NW.  Light from a cenote was seen near the last station YXRG17.  Several leads were seen to the south and SW, two of which were noted, on survey.  This area is the largest area of the cave we have seen to date and no doubt will eventually lead to the last two major cenotes in the chain as well as leads toward the SW.  I called the dive on air, needless to say the cave continues.  Roughly 22 minutes of deco were eliminated during the scooter out.

5/21/98 Clean-up set-up dive, Gary and Kay
40ft/70minutes
This short dive to the L shaped cenote was to exchange full stage tanks for the empties from the last exploration dive.  The next push is planned to start 1400ft short of the end of the line where an unexplored SW tunnel off of the Rio Grand line probably leads to another extensive cave area.

5/24/98 Exploration dive, Gary and Kay
65ft/323minutes, 1244ft of line installed.
Double scooter, triple stage.
This new line called Southpark starts off the Rio Grand line upstream at YXRG4.  The line passes through a canyon that heads south and then splits with a west lead and SE lead.  The SE was chosen this dive b/c it was feared that the west would lead back into the Rio Grand line.  On a later dive this should be checked b/c a turn to the SW at that point would lead into a new section of the cave that may be extensive.  As it is the Southpark line runs along the south wall heading downstream and gives an idea of the width of the drainage off the mainline, roughly 1,400ft.

6/2/98 Science dive, Kay and Sam
Entry pool/71 minutes.
Sam Smith is the water specialist for Centro Ecologico Akumal. She is a divemaster and a scientist interested in studying the hydrology and biology of the Akumal area with a specific interest in caves.  
 Water samples were taken in the downstream cavern of Yaxchen at the beginning of the Chupa 1 line.  Additional samples were taken @30 feet up the main upstream line that begins at the western end of the entry surface pool and from the center of the main surface pool.
 Samples were also taken from the Crack line in the cave zone, both above and below a white hazy cloud layer that is in this area.
 Samples will be tested for salinity, nitrate, nitrite and fecal content.
 Biology specimens were taken of the mussels that live in the cave, the sponges and a white fibrous material that is on the cave floor and in the surface pool.  All of these specimens were from the downstream section of the cave, Chupa 1 line.
 Upon completion of the dive all the samples were iced down and taken directly to the lab in Akumal for analysis.

6/9/98 Science dive & set-up/clean-up, Gary and Kay
55ft/84minutes
Four water samples were collected from the "milky way" passage between Tarpon 1 and Tarpon 2 cenotes.  A double whitish vapor layer exists there where water samples were taken.  The first is at 36ft of depth, the second 40ft.  Samples were also taken at 30ft and 55ft, above and below the layers. Also, an orange and white-banded shrimp was seen crawling on the floor at approximately 60ft of depth below the white layers. 
 The Tarpon 2 cenote was orange/red in color above 10ft of depth on this dive.  A distinct thermocline in the tannic layer above 10ft was noticed with a number of tarpon fish seen swimming about.
 Stage bottles were exchanged at the first scooter drop point.

6/13/98 Exploration dive, Gary and Kay
54ft/345minutes, 290ft of line installed
This triple stage, double scooter dive was an attempt to push the western extreme of exploration at the previous end of the Rio Grand line.  Both the water current and our aerial photographs suggest that the main water source for the system may pass through two large cenotes that lie nearby to the west.  These would be the last two cenotes in "The Chain", in Spanish "La Cadena", and their connection would fulfill one of the goals of the project. Since this area is the most distant point from our entry cenote every push dive requires some increase in either efficiency or equipment.  For this dive we over pumped our backmounted tanks and tried a scootering technique called 'training' or 'drafting' where one diver follows directly behind the other in order to reduce drag.  To accomplish this we used the 1-1/2 inch split ring on our crotch straps that we normally use to tow a second scooter behind.  This ring is not sewn into the harness as most scootering rings are and therefore can slide back freely between the legs making towing, clipping and un-clipping by either diver quite easy.  In order to "draft" the lead diver, the second diver simply attaches a small removable clip to the front of his scooter and then clips it into the lead diver's moveable tow ring.  This technique was used after the first scooter drop.  Arriving at the first drop point we discovered that a leaking tank valve O ring on one of the set-up bottles had reduced its pressure to 2700psig.  In addition run times to both drop points were longer on this day indicating an increase in the flow.  
 Despite these problems we did have some extra air in our backmounts when we arrived at the previous end of the Rio Grand line and added 290ft of line.  The passageway ended in a large room with a decorated ceiling and debris slope containing leaves and sticks.  A vertical crack ascended to an openwater area emitting reddish daylight from above.  Because of the restriction we could not investigate.  This point is 12,494ft from our entry area.  We surveyed our new addition and then backtracked @200ft to check another area just north of the line where Kay had spotted light on the previous upstream push.  We ascended to see a submerged fallen tree and debris pile with white opaque water above.  New passageway could lie on the other side to the north but air limitations did not allow us time to investigate.
 Thirty minutes of decompression was eliminated during the exit swim and scooter ride out.  Kay's second scooter gave red light battery low warning approximately 1000ft from scooter drop point one.  This 1000ft is almost all openwater at cenote Largo into the L shaped cenote.  The situation was easily resolved by towing and reducing the speed control on my scooter.  Perhaps the tandem 'drafting' technique and additional flow caused the problem by over-taxing Kay's scooter on the way in.  I exited the cave with 1/3 air remaining and Kay, of course, with more.

7/8/98 Clean-up/ science dive, Kay and Gary.
40ft/78minutes
This dive, to the first drop point at "L" shaped cenote, had the dual purpose of removing the used tanks from the previous upstream push and taking a water sample from the Tarpon 1 cenote.  Recently the surface pool at Tarpon 1 has turned a deep red above 10ft of depth.  This "red" layer has been warmed by the sun, creating a noticeable thermocline that seems to be preferred by a number of large tarpon.  This red phase occurs periodically at Tarpon 1 cenote and is probably caused by tannic acid from dried mangrove leaves being washed into the pool by rain.  A sample was taken.  Below the layer the traversing cave water is a normal blue/ green color.

8/1/98 Tour dive, Kay, Samantha Smith, Gary.
27ft/90minutes
This was a familiarization dive for our biologist Samantha Smith.  A dive up the main line to Tarpon 1 cenote and across the surface pool to the beginning of Main Line 2.

8/6/98 Science dive, Gary and Sam S.
31ft/99minutes
Out of the entry cenote the Crack line was taken south through cenote Sur and then jumping to the Tarpon 1 to Sur line.  Two water samples were taken and a sediment sample.  The first water sample was taken approximately 5 minutes into the dive toward the top of the vertical fissure along the Crack line, and the second sample was taken just b/f entering cenote Sur.  A sediment sample was also taken from the floor between the entry cenote and cenote Sur.

8/18/98 Set-up dive, Gary and Kay
27ft/71minutes
This single scooter, double stage dive took us approximately 3700ft in to the west side of Tarpon 2 cenote.  Four stage bottles were placed, unused, in preparation for a quadruple stage, triple scooter dive.

8/19/98 Set-up dive, Gary and Kay
41ft/156minutes
This double scooter, double stage dive took us 7300ft in to place two full stages at the second drop point.

** Note:  A practice session was done in an area cenote in order to practice towing two scooters while being pulled by one.  This technique proved to be fairly easy and only required the addition of a six-inch piece of light bungie used to hold the two towed scooters together where the propeller shroud meets one of the four stanchions.  The scooters' leash clips, once passed through the carrying handle at the top of each scooter, are then clipped to the diver's movable split ring on the crotch strap.  If all is in order the scooters should float behind, side by side, above the legs while scootering.  It should be noted that the triggers on all scooters must be cross-drilled with wire locks installed so they will not 'come to life' while towing.  Towed scooters must be neutrally buoyant!
 Because the water in Yaxchen is brackish and therefore more corrosive we decided that we would first place all stage cylinders for push dives in the cave and then, on the day of the triple scooter push dive, use a single stage tank to get to the first drop point thereby limiting drag.  During this first leg of the dive we tow two neutrally buoyant Mako scooters.  On exit we bring out all the scooters, thus avoiding corrosion problems and allowing for recharging of all the batteries shortly after use.

8/22/98 Exploration dive, Kay and Gary
67ft/399minutes, 489ft of line installed
10ft/25minutes remaining deco at entry point.
The triple scooter ride took us 10,500ft upstream to begin our swim.  Just beyond 12,000ft we dropped our final stage tank and went on our backmounted gas.  A lead to the north and into a cenote with white opaque water didn't pan out.  Further attempts to the north still didn't reveal a definite continuation to the main passageway.  Turning for a look on the SW side of the Rio Grand line an opening was spotted that descended to the 60-70ft level and into a phreatic bedding plane area.  Pushing to the west we could only install 489ft of line before the passage pinched off.  While exiting a couple of other possibilities were seen along the Rio Grand line.  These will be checked out in the future in hopes of locating the continuation of the cave toward the west.

8/28/98 Exploration/ clean-up dive, Kay and Gary
53ft/134minutes, 735ft of line installed.
A single scooter dive was made to the first drop point with the dual purpose of bringing out four used stage tanks from the previous upstream push, and checking a deep area in the 'Milky Way' passage between the 'Tarpon 2' and 'L shaped' cenotes.  735 feet of line was laid and surveyed and a new line established named 'Fantasma' or 'Ghost' in English.  The skeletal remains of what appears to be a crocodile and numerous small fish were discovered in the process.  The floor of this area is below the halocline with no flow whatsoever observed.  A distinct sulfur odor and a tarnishing of our brass clips indicate that hydrogen sulfide is present in the water.

9/2/98 Exploration dive, Kay and Gary
31ft/120minutes, 897ft of line installed.
This exploration extended the end of the Tarpon 1 / Sur line that connects cenote Surito to the system at it's eastern end.  Surito is located SSE of the entry cenote.  Siphoning water was followed to the SSE through small cave and a couple of openings in the mangrove above, finally passing through a very silty area that may continue sidemount.  This area confirms once again the siphon split at Yaxchen, with most the water going NNE above the entry cenote and a smaller amount heading toward Laguna Campechen to the South.

9/7/98 Exploration dive, Kay and Gary
39ft/132minutes, 716ft of line installed.
On this dive we returned to the Southern region of the cave to investigate a passage that looked likely to provide a short cut between two lines.  East/ West passage connected the eastern portion of the zigzag line to the Campechen line, coming in at a cenote opening.  It is around this area that the siphon split occurs.

12/8/98 Exploration dive, Lamar Hires, Kay and Gary
54ft/210minutes, 946ft of line installed.
This double scooter, double stage dive was planned to check out the area SW of Oasis cenote which lies roughly 7,000 feet upstream.  Line was laid SSW until a peat/ mangrove blockage was encountered in the vicinity NW of Izod 2 cenote.  The line was then pulled back somewhat and redirected to the NW.  An open lead to the NW should continue toward the Southpark line on the next exploration push in this area.

1/31/99 Exploration dive, Dan Lins, Kay and Gary
57ft/227minutes, 1678ft of line installed.
This dive was a follow-up to the exploration dive reported above.  We returned to the area SW of the Oasis cenote in the upstream portion of the cave and started our exploration at station YXLMR4.  With a plan to head west Dan proceeded to lay line in that direction and then NW and SW.  The area is leading toward the Southpark line located farther upstream and will probably connect on later dives.  Also passage may be found leading to a new SW area of the cave.

2/7/99 Exploration dive, Harry Averill, Kay and Gary
42ft/124minutes, 478ft of line installed.
A single scooter, single stage dive upstream with Harry Averill established a new line to traverse between the southern end of the "L Shaped" cenote and cenote Largo at it's southern end.  Another opening was connected in the process about midway down the line.

2/16/99 Exploration dive, Tim McMann, Kay and Gary
38ft/201minutes, 1063ft of line installed.
This single scooter, double stage dive was to investigate the area NE of the main tunnel between cenote Largo and Izod 2 cenote.  Two lines were installed and with some leads remaining [to the south] that should lead back to the main line.  No open leads seen to the NE.

3.5.99 Exploration dive, Kay and Gary
47ft/196minutes, 643.5ft of line installed.
On this dive we decided to push the downstream line headed north.  The downstream section is generally much smaller than the upstream with deep silt and several tight restrictions.  On this dive we opted for double 80 backmounts, two 80 stages and single scooters.  This was a bit challenging through the small stuff.  Zero vis and falling ceiling chunks were encountered several times with all the gear strapped on.  Many leads remain to be checked out, some heading west.  The flow continues to meander north.

3.7.99 Exploration dive, Gary and Dan Lins
44ft/195minutes, 1220.5ft of line installed.
This dive downstream established a new line and eastern extent to the cave.  It starts at station YXCHF13 and heads SE toward the end of the Chupa 3 line.  Several leads were noticed, one in particular heading NE.  In addition this line could be used as a short cut from "the hole" to Chupa 4 line and the northern end of the downstream line.

3.23.99 Exploration dive, Kay and Gary
28ft/92minutes, 478ft of line installed.
On this dive line was added to the end of the SE Folly line and a new line was also created called the Get Small line.  This area is just SE of the entry area and is characterized by small silty tunnels.  One section of the Topping line was found broken and buried under the silt by rock fall from the ceiling.

3.27.99 Exploration dive, Gary
31ft/102minutes, 772ft of line installed.
This sidemount dive established a connection between the cave zone at cenote Sur/ Surito and the cave zone just east of the Yaxchen entry cenote.

3.28.99 Exploration dive, Gary
29ft/119minutes, 413ft of line installed.
Another sidemount dive done to follow the siphoning current passing down the Chupa 1 line.  The line was started at station YXCH19 and ended at one of the downstream cenote openings that the Chupa 2 line passes through, around station YXCHT26.

4.02.99 Exploration dive, Kay and Gary
45ft/175minutes, 1081ft of line installed.
This dive to the downstream section established a short cut line to the Chupa Scooter line and also installed 2 lines to the east of Chupa Scooter.  Survey will be taken of these lines on a later dive.

5.25.99 Survey dive, Kay and Gary
46ft/152minutes, @1081ft of line surveyed.
Survey of the above exploration.  Three lines were installed; the ‘cut across’ line, the ‘mangrove opening’ line and the ‘where’s the beach’ line.  The opening at the end of the ‘mangrove opening’ line may become a new entrance for pushing the downstream section.

5.28.99 Find the cenote dive, Kay and Dan Lins
46ft/137minutes
This objective of this dive was to locate the opening at the end of the ‘mangrove opening’ line.  After approximately 50 minutes the divers surfaced at the opening at the end of the line while another land team waited and listened for their whistles and whooping calls from above.  Upon hearing the sounds a path was cut through the dense mangrove to reveal two heads crowned in neoprene and masks poking out of the ground under heavy underbrush.  The divers were found by Chris Lins [Dan’s son] and Gary.