July 2-8, 2010
Report written by Dr. Al Amores
- Paul Neilsen, Overall Coordinator and Technical Director, IANTD ITT #38, Tech Cave Instructor
- Doc Amores, Expedition Organizer, LGU Liaison Officer and Dive Coordinator, NACD (USA) #3042
- Scott Livingston, Equipment & Logistics, IANTD Tech Cave Diver # 95507
- Iain Duncan, IANTD Tech Cave Diver #16330
- Trendy de Ramos, IANTD Tech Cave Diver #95493
- Patrice Laborda, DSAT Tech Trimix Diver #1001AE6145, graduating IANTD Tech Cave
- Mak Jonathan, CDAA (Australia) #4049
Expedition 2 is a sequel of the first expedition conducted by MAD (Mantaga Adventure Divers) in February 2010. Expedition 1 was a planned preliminary series of cave dives to look into the possibilities of Hinatuan Enchanted Spring Underwater Cave after reports surfaced following a couple of non-technical dives by non-cave divers. It defined a very difficult constricted 12-meter passage (Bernil’s Crawl) going against a strong current opening through a door (Doc’s Door) into a wide no-current chamber (Mayor’s Chamber). The farthest extent of the dive was 10 meters from Doc’s Door.
Expedition 2 is planned to define Mayor’s Chamber, and time and resources permitting, to push beyond.
TECHNICAL DESCRIPTION OF HINATUAN ENCHANTED RIVER
The full technical description has already been published in Expedition 1 report. Briefly, Hinatuan’s Enchanted Spring is 14 km north of town. It is a natural spring/river that is fast becoming one of the favourite tourism destinations in Mindanao. Unbeknownst to most, the spring/river is fed by one of the world’s exciting underwater caves, based in its water quality, topographical and geographical features, and depth.
THE SURVEY DIVES
Through one week of dives the following is established: there is a constant outflow current that goes stronger as the tide recedes.
The team resources are much more sophisticated and technical than that of Expedition 1. The team is properly equipped with trimix mixes and closed circuit rebreathers. The team set a limit of depth of 100 meters.
Owing to the labour-intensive nature of transferring and set-up of our equipments the first dive did not start until noontime of Day 1. It took many people a few trips up and down Enchanted River on our shuttle boat, provided by Mayor Viola, moving our equipments from our home yacht, the Noble Warrior, anchored in the bay just outside the mouth of the river.
Due to the complicated interplay between depths and types of gases used by the different teams, thorough pre-dive planning was done before every single dive. As well, immediate post-dive debriefings were done to accurately record the findings and events. Doc Amores conducted the planning and debriefings, with Paul Neilsen wielding full veto power.
The first two dives were getting-acquainted-with-the-cave dives. The initial worries of too strong current and severe constriction going in were assuaged by the discovery of Patrice’s Way. This path was discovered by the team of Paul and Patrice on Dive 2. Bernils’s crawl is a 12-meter ramp going down on a 40-degree angle tapering towards Doc’s Door corridor. Without a pull-and-glide purchase, entry is hampered by the strong current. Additionally, a couple of severe overhead constrictions block easy access on back mounted gears. Patrice’s way is a no-current “stairway” to the left of the ramp bordered by a log lying along the edge of Bernil’s Crawl. Just past the first slight constriction, the path goes over the log and down to a meter and a half wide valley of limestone rubbles held by another log running parallel to the previous one. Another step down is a short corridor running to the right ending at the bottom of the ramp where a slight current is noted. This shortly takes one to the corridor leading to Doc’s Door. Initial tries going straight down Bernil’s Crawl took an average of eight (8) minutes from the surface to Doc’s Door. Via Patrice’s Way, travel time is reduced to around three (3) minutes.
Following discovery of this easy access, survey of Mayor’s Chamber went into earnest. The survey was transect-based using a line (the gold line) marked by a knot every 3 meters. The line starts from a point just inside Doc’s Door tied on a long iron bar hammered deep into the limestone floor going straight to the far end of Mayor’s Chamber marked by a promontory resembling a knee cap. This is now named Kelvin’s Knee Cap. (Kelvin is a member of the team who arrived from Hong Kong at 4 AM, went straight to the Noble Warrior, and at 6:30 in the morning fell off the deck and hit his left knee against the edge of the dock, severing the knee cap attachments. He was ambulanced to Perpetual Succour Hospital to meet his orthopaedist shortly before the yacht left port). The gauge depth at Doc’s Door is 42 meters, at KKC 52 meters. The line from DD to KKC runs at a compass bearing of 270 degrees. Cookie markers were installed at an every-third-knot sequence, completing the reference line. From these, measurements were made sideways for the width, and up and down for the height of Mayor’s Chamber. For these measurements, the group was divided into sub-teams comprising of Jonathan-Doc, Iain-Trendy and Paul-Scott-Patrice.
In the middle of MC the water is fresh.
While the survey was in earnest, Paul began pushing beyond Mayor’s Chamber.
Mayor’s Chamber, at its longest point is 37 meters long and at its widest, 31 meters. It is 8 meters at the highest point from floor to deck head. The gauge depth at Doc’s Door is 42 meters, at midpoint is 54 meters and at Kelvin’s Knee Cap, is 50 meters.
THE PUSH BEYOND MAYOR’S CHAMBER
The initial push was done by Paul up to the depth of 76 meters. This is now Paul’s Passage. Subsequent pushes of up to 87.5 meters deep on the gauge and 90 meters on the line were done by Iain and Trendy. The line ends in a sharp bend going steeply upwards. The area is now called Jonathan’s joint. To the end of the line, the turn-around time is 28 minutes, total dive time of 120 minutes using Trimix 14/40 on the rebreather back gas. No actual measurements were done on this expedition but Paul’s Passage is described by Paul, Iain, Trendy and Jonathan as a series of constrictions and wide spaces ending at Jonathan’s Joint in a series of convoluted turns and twists sometimes with significant restrictions. Compass directions-wise, KKC to entrance of PP is on the bearing of approximately 300 degrees; from PP entrance to JJ is approximately 240 degrees. At JJ, the water is brackish as tasted by Jonathan.
Expedition 2 is heavy on equipments and technologies. The resources provided for 5 closed circuit rebreather divers and 2 open circuit divers. On the trip going in, the Noble Warrior, our home-base yacht was littered all over by our individual equipments, stage and deco tanks, compressor and booster pump, and big tanks of oxygen and helium. Not to mention luggage, provisions for the trip and other personal items.
Equally, the expedition would hardly been possible without the help of the community of Hinatuan, lead ably by Mayor Candelario Viola, Jr. On the get go, coordination of the Hinatuan side was handled by Mr. Ferdinand Barrios, Municipal Planning and Development Coordinator. The community of Hinatuan handled half of the expenses of this expedition through the excellent board and lodging facilities (the food was excellent every day as judged by Patrice, our Frenchman food connoisseur. Paul thinks he gained 4 kilos on this expedition) and cost of the fuel on the trip back to Mactan.
In the context of cave diving at different skill levels and capabilities, Hinatuan Enchanted River Underwater Cave is composed of two sections as currently observed. Mayor’s Chamber, although a bit challenging on the ways in and out is a comfortable dive within limits of air as back gas (21%Oxygen). A typical turn-around time of 15 minutes is well within the thirds rule of most cave divers. Using 50%oxygen as decompression gas, the total dive time is around 60 minutes. Beyond MC and into PP is the realm of trimix divers. On trimix 14/40, and turn-around time of 28 minutes, the total dive time is around 120 minutes. A 7-meter gap between the end of the MC gold line and start of PP gold line was purposely made to stress the separation of these two areas.
Expedition 2 met its prioritized goal of defining Mayor’s Chamber …and more. Easy passage to Doc’s Door was established. Perhaps, the biggest find is Paul’s Passage that leads to more than 90 meters of complicated spaces at a maximum depth of 87 meters.
The following holds big promises for further discoveries:
- The tunnels and spaces beyond the line at Paul’s Passage, noted to be inclining upwards in a slightly sharp angle, containing brackish water.
- Two openings to the Mayor’s Chamber around the ceiling to the right and to the left of the area of Kelvin’s knee cap.
- Possible navigable cracks in the wall/ceiling of Mayor’s Chamber especially one to the upper right of Doc’s Door facing the exit.