Posts Tagged ‘cave diving’

April-May 2019


I recently had the opportunity to test a cave light made by Nanight of Sweden. This was through the kind arrangement conducted by a good friend and fellow dive instructor Kent Barquin of Chicago, Illinois.

Kent also lent me his personal Nanight light products which were a pair of Sport video lights and a Tec2 light. All the Nanight lights performed superbly but this review is focused on the Cave3 light since it is the newest addition to the Nanight line-up.

Testing of the said Cave3 light was made in both freshwater and saltwater environments.


At Pawod Underwater Cave System with (L-R) Jaime Lapac, Art Gardiner, Dean Apistar, author

Getting ready to dive the Liloan Ship Wreck with (L-R) Jaime using the Cave3, author with the Sport video lights and Nelson Que with the Tec2 lights.

The Nanight Cave3 is a 4000 lumens LED light with an umbilical head and a canister battery packed with 24,000ah of battery power.

The light was used in sidemount diving set-ups. Maximum depths reached during testing in a freshwater cave was 25 meters. Saltwater testing was made on a shipwreck to a depth of 45 meters.

Average dive duration during the tests was 1 hour.

Initial Observations:

Things inside the goody bag.

1. Attachment of the battery canister to a tank can be made via a supplied velcro strap.

2. Attachment to the waist strap (backmount) or crotch strap (sidemount) can be done using the pre-attached 2 pieces of hose clamps and webbing.

Attached on the crotch strap for sidemount diving.

3. Options available to use a carbon-fiber Goodman handle or a soft/ multi-mount Goodman handle. Both said items are supplied in the package. I liked the soft handle.

Observations During the Dives:

1. Intensity of the light is noticeably higher, and the beam is more focused compared to a Chinese made 3000 lumens light that I used for comparison (Cave3 is 1000 lumens higher).

A strong beam is fine in certain environments but if you’re diving in a site with a lot of suspended calcite particulates, such as in certain points inside Pawod cave, a strong light beam will result in a high back-scatter. You will experience something akin to driving on a foggy road with your car’s white headlights set on high beam.

We reduce back-scatter by shifting light power to the lowest setting. The Cave3 has two light settings but the lowest one is still strong in comparison to the other brands we use that has 3 levels of power intensity.

2. The lamp head is neutrally buoyant in fresh and salt water. This takes out the possibility of disturbing the silt if one should accidentally let go of the light. I really liked this particular feature.

3. Fully charged, it took a long while for the power to drain during use. Although we did not conduct an comprehensive battery test, I was pleased to note that I did not have to wait too long for the battery to charge after a long day of diving since it still carried a lot of power inside it.


Upper left is the beam of the Cave3. Lower right is from the Tec2.

4. The strong beam allowed me to see more details inside the cave and the wreck. I particularly enjoyed the fact that although the sites we dove were well known to me, the excellent illumination by the Cave3 light gave me a fresh view of the sites.


I can wholeheartedly recommend the Nanight Cave3 since it has a durable construction, excellent battery life, non-corroding components, strong beam and overall good feel to it.

The downside though is the cost of the product which might be an issue for divers who already made substantial investments for their existing equipment.

It behooves the new cave or technical diver to consider the Nanight Cave3 as his or her first primary light purchase. There is no doubt that this product will easily survive the challenges of the underwater environment and will be of service for many adventurous years.

Link to manufacturer’s site:


What I found lacking in the manual was a clear information on how to separate the umbilical cord and the battery canister to allow one to charge the battery. I searched through the internet but I did not find any details to perform the procedure.

Here then is my method:

1. Find a rubber strap, the ones you use to retain your hose on your SM tanks will do very well;

Fig. 1

2. Wrap the rubber strap at the base of the area where the umbilical cord starts (Fig. 1);

3. Grasp the battery canister with your left hand and with your right hand take the other end (use opposite hands if you’re a lefty);

4. Firmly rotate to the left the battery canister and rotate to the right the other end with the rubber strap;

5. The seal is very tight so be patient and do your darn best;

6. Once open, slide out the battery and do what you need to do (Fig. 2).

Fig. 2


  1. Thanks a lot to Kent Barquin for making available the excellent Nanight lights for us to try.
  2. Thanks to my buddies who tested the products with me– Jaime and Nelson.
  3. Thanks to Jaime’s Dive Center for the logistical support.
  4. Thanks to Nelson Que for sponsoring the use of the boat to the Liloan Ship Wreck.

Disclaimer: The author was not under any agreement with Nanight to conduct a review of their products. This review was made through the initiatives of the author.

Filipino Cave Divers

The Filipino Cave Divers team. L-R: Lyndon Cubillan, Doc Amores, Jake Miranda, Bernil Gastardo


It was another day in paradise on June 23, 2013 as we made our way to Larry Williams’ banca for the trip to Dinagat Island at the break of dawn. We left from Jake Miranda’s Punta Bilar Dive Shop in Surigao del Norte. The sea was flat and the sky was clear.At the break of dawn.

It was the 3rd day of our Southern Expedition that started in Butuan. But we were supposed to start the trip from Davao. My research showed that there is an area in Davao Oriental that may have the same potentials for exploration like the Hinatuan Enchanted River.

All rights reserved to the original photographer.

Lake Carolina, Davao Oriental

The prospective site is called Lake Carolina  and the photos I found on the internet showed a blue pool of undetermined depth, nestled among coconut trees and jungle foliage.

It was 2 days before our flight to Davao to meet up with Jake, Larry (driving from Surigao del Norte) and Lourdes (flying in from Manila) when news broke out that a couple of government soldiers and civilians were shot at and kidnapped by insurgents in Davao del Norte.

We wavered a little on the decision and the possibility of not changing plans but we definitely changed our minds as soon as Jake informed us that his military contacts have positively identified the sector in Davao Oriental leading to the Lake Carolina as “Red-Hot”!

Jake is featured in the airline magazine.

Jake is featured in the airline magazine.

The new itinerary was to fly to Butuan, then drive to Barobo to assess a potential site and then proceed to Hinatuan to continue the exploration of the Enchanted River.

Our muses

Lourdes Alejan & Jeanne Dumlao

Ok, but the  interesting thing was that Lourdes Alejan, our seemingly fearless geologist thought that she might as well meet us at an area on the way to Barobo.

When we saw her mid-morning of June 20th, she told us that she took the overnight bus from Davao. Surprisingly,  the bus route went through the “Red-Hot” zone we were trying to avoid! What the …!!

All is well that ends or starts (?) well and so there we were on that fine day, healthy, alive and all accounted for, headed out to Dinagat to traverse the Lake Bababu. The tunnel that starts from the sea and ends up in a freshwater lake was initially explored by FCD Lyndon Cubillan on August 28, 2012 and first traversed by FCD Jake Miranda on September 7, 2012. Jake wrote a fine article about the awesome experience of diving from the sea and coming out to the lake.

With an approximate length of 2, 200 ft/ 650 meters, Lake Bababu Underwater Cave is considered the longest fully-submerged cave in the Philippines!


Info made by: Jake Miranda


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Peaceful scenery Dinagat and SurigaoDinagat Island is an enchanting area with an allure that may remind one of the top-side beauty that Coron, Palawan offers—minus the sight of other tourists.

The eastern coast of the island fronts the Pacific Ocean and the south-western side faces Surigao del Norte. Travel time to the site took 2 hours.

Picturesque white-sand coves and uninhabited islets along the way served as icing on that sweet day. We anchored the outrigger boats on a still and calm cove beside a high limestone cliff.

Directly above the cave’s entrance are warning signs placed by Jake and Lyndon.

The tunnel starts at a depth of 9 feet/ 3 meters and the tidal current was predicted to gently flow in from the sea to the lake on that certain time. We expected to have the leisurely condition of being carried through the tunnel. A more relaxing cave dive could not have been envisioned!

Getting ready for an epic traverse!

Jake was the lead man with Doc as his buddy. With our cameras, Lyndon and I teamed up to document the traverse. Each diver was equipped with 4 units of 80 cu/ 11 liter tanks to fully cover any issues with gas requirements. Total expected time from start to finish of the dive was 70 minutes with 20 minutes of possible decompression obligation.

Filipino Cave Divers

L-R: Lyndon (twin tanks & 2 stages), Doc (4 sidemount tanks), Jake (twins tanks & 2 stages)


Underwater, Jake signaled OK and everyone responded the same. Poised near cave’s mouth, Jake started to fin forward and was swiftly carried in. Doc followed suit, next was Lyndon and the last to go was me. The current started with a gentle push, slowly nudging—but when we were fully inside the cave the push became a shove and then we got flushed into the tunnel! Imagine a water slide—yep, something akin to that but in this ride, you are in a long, dark, enclosed space with jagged things out to cut you and your equipment if one is not careful.

Touch and cry.

Stinging hydroids on the rocks. Nasty.

“This is going to be one hell of a roller coaster ride!” I thought as I sailed past stinging hydroids growing on the sharp, coralline sides of the cave. The floor was covered with a collection of small shells from bivalves long gone. Perimeter clearance was less than a meter on each side and a meter from the ceiling to the bottom.

5 minutes into the dive, we came to a 30° right turn that required us to slow down but the current won’t allow us that privilege. I could hear tanks banging as the 3 guys made contact with the sides of the cave and with each other. I dropped down closer to the bottom and positioned my left tanks to prepare for collision. Shifting sideways, my left tanks slammed into the wall jerking me upward and making my helmet scrape the ceiling. Ah, thank God for helmets!

Interesting rock formation

It went on like that for 30 minutes, more or less. Turn! Bang! Scrape! Repeat. I started to get a good idea of how the ball in a pin-ball machine might feel while being played.

A respite from the wild action occurred whenever we found ourselves in larger spaces where the strength of the water flow was less.

Bottom crawler

Speaking of large areas, there is a Cathedral-like chamber where I found rock formations rising from the bottom and coming down from the ceiling. Stalagmites and stalactites? Perhaps…

Another interesting experience was the challenge of maintaining buoyancy whenever we came to a point where fresh and saltwater mixing occurs. I’d be trimmed and neutrally buoyant for saltwater and then suddenly I’m dropped to the bottom as the water density changed.

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Tired but happy and alive.

Doc resting with “souvenirs” on his back.

We rounded another corner and we observed several small yellow sponges on the bottom. The current was slowing down and in a distance I could make out a faint greenish hue. We have reached the end of the tunnel, we are in the lake!


Near the exit, I saw Doc on the bottom having a rest after the adrenaline filled ride. The back of his Hollis carried “souvenirs” — parts of the tunnel that dropped loose as we passed through. Jake came up and we all shook hands, congratulating each other for the successful traverse!

I tasted the lake water and it was fresh, which was interesting because I then saw 2 big trevallies (jack fish) swim past.

MoonscapeWe had incurred 19 minutes of decompression time which we had to clear at a depth of 6 meters before we could ascend to the surface. We used that time to swim slowly towards the lake shore.

The surreal landscape enclosed in greenish water lent more mystery to the tangle of fallen tree trunks. I noticed small sea urchins on the rocks and again, the trevallies.

selfie!My dive computer cleared of the decompression requirement and I slowly made my ascent. The first surface image I saw was enthralling! Tall limestone walls surrounded me with trees and foliage bordering the water’s edge. The water was flat and still and everything was peacefully silent. I saw small transparent freshwater shrimps and silver half-beak fishes swimming among the tree branches & leaves overhanging into the water.

Can't beat the view.Larry, Lourdes and Jeanne were waiting at a small shore. From the beach, they had to follow the trail up on a hill and then down to get to the lake. It took them approximately 30 minutes of good hiking through a path cut out from the jungle that covers the island.

The team was tired. We rested and lunched on the fine packed meal prepared by Larry’s lady, Ayet. Good food, great ambiance, fine company—ahh, such is life.

After a relaxing hour or so, we decided to pack up and head back to Jake’s shop. What awaited us between our current location and the boat was the trek up the steep hill, through the rocky forest path and down to the beach. And boy, was that a trek!

Thank God for the local porters because without them we would have died. No pun intended, really! Imagine making the trek carrying the tanks and other stuff after a decompression dive. The porters did an excellent job of maneuvering through the rocky uphill and downhill path while carrying such heavy equipment.


My hero!

I wore my sidemount harness with lights and reels attached, and I was panting all the way up and all the way down. The guys carrying our tanks were passing us with smiles on their faces. I tell you, they are God’s gift to explorers.

After 30 minutes of trekking, we came upon a sight for sore eyes. The secluded beach was impressive!

The beach!

We met up with the caretakers of the site and we showed them the videos we took of the traverse.

Smiling locals, happy to see what's the hidden beauty of their island.

On the way back to Surigao, we passed by areas of immense beauty. Dinagat Island and the Lake Bababu are so awesome that I silently promised to myself, I will be back.


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Doc, Bernil, & Lou

Another invitation from the ever supportive Mayor Candelario Viola Jr. and Municipal Planning Officer Mr. Ferdinand Barrios brought us back to Hinatuan, Surigao del Sur.

The team was composed of Doc Amores, Lou Holder and yours truly. The trip was conducted from June 11-14, 2011.



The strength of the water flow that hit my mask sideways half –flooded it when I turned to check on Doc and Lou. Hinatuan Enchanted River was coming at us extra strong and it took us all by surprise!

Clearing my mask quickly, I signaled to them the OK sign, and they gave me the same signal back.

29 meters/ 95 feet deep and 10 meters from the lip of the cave, the bubbles from my exhalation and the water rushing out and bouncing against the rock walls of the entrance sounded like traffic on a busy freeway. I did my best to lie as flat as I could on the gravel bottom, and with my arm muscles straining, I moved inch by inch deeper into the cave’s entrance as the strength of the spring water did its best to push me back out.

I had my 11 liter back-mounted twin tanks on and I left firmly clipped to the wooden log at the cave’s lip my 2 stage decompression tanks loaded with 50% and 100% oxygen. Doc was using his Evolution Closed Circuit Rebreather (CCR) and Lou had his Inspiration CCR.

Because the exhaled breaths of Doc and Lou were retained and reused by their life-support system, they didn’t produce any noticeable bubbles but I was pretty sure they were breathing as hard as I was with all the effort needed to maintain forward movement in the raging water flow.

The objective of this trip was to conduct surveys further into the Hinatuan Enchanted River Head Spring up to the depth of 90 meters/ 295 feet.

Hinatuan Enchanted River Head Spring Diagram by Doc Amores

We packed heavy on this expedition, anticipating the amount of required tanks and gas (Oxygen and Helium) to sustain us safely to the intended depth and back.

Similar to the first time we visited, the very kind Mayor Viola and the master organizer Mr. Ferdinand Barrios showed us their full support and the logistical challenges were easily managed.

Special mention and best of thanks again to Mr. Jake Miranda of Surigao Dive Club for lending to us a compressor and extra tanks. We would not have been able to complete our gas blending requirements without his help.

Click to the next page: VORTEX

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 The 1st Hinatuan Enchanted River- Surigao del Sur Exploration was conducted on Feb. 19- 21, 2010.

Mantaga Adventure Divers

Bernil, Emgee & Doc


  • Dr. Alfonso “Doc” Amores – NACD (USA) # 3042
  • Bernil H. Gastardo – IANTD Technical Cave Diver #95508


  • Emmanuel “Emgee” Guillermo, PADI Advance/Deep Diver
Report by: Doc Amores


Hinatuan’s Enchanted River is a favourite tourism destination in the island of Mindanao. People as far away as Davao, a 6-hour bus ride away, take day trip excursions just to enjoy this natural wonder – a spring with cool crystal clear water, flowing out to sea some 600 meters away. The head spring is surrounded by up to 40-meter cliffs of soft limestone and lush vegetation.

There have been up to 3 dive explorations of the area, all by non-cave divers. This expedition is an attempt to define the nature and topography of the depths of the Enchanted River head spring. It is a joint effort of MAD (Mantaga Adventure Divers), a group of cave and associate divers from Mactan Island, Cebu and the LGU of Hinatuan, Surigao del Sur.

MAD Cavers making a courtesy call to Mayor Candelario Viola Jr…

The LGU is represented by Hon. Mayor Candelario J. Viola, Jr of Hinatuan and Mr. Ferdinand Barrios, Municipal Planning and Development Officer.


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By Bernil H. Gastardo

The Pawod Spring area as it looked on that eventful day of May 2007.

“Let’s eat so we can die with a full stomach,” said my instructor Paul Neilsen. “Lovely…,” I thought.  We then started on our lunch of inasal manok (roasted chicken).

That afternoon, we were to do the final dive for my IANTD Technical Cave course.

The dive objective was to penetrate “Paul’s Peril”. This tunnel goes further and deeper into Pawod Cave. Running 30 meters farther from the main chamber, its maximum depth reaches 18 meters/ 60ft. Only a handful of men have previously penetrated this tight restriction. I was to be the 5th one allowed the privilege.

Schematic Diagram by Doc Amores

docThe Pawod Cave was discovered by Dr. Alfonso Amores. Trained in cave diving techniques in the freshwater caves of Florida, he is the first diver ever to shine his light into the cave and lay a line around the main chamber. In his childhood years, he was one of the many kids that used the cave’s main pool as a swimming hole to ward off the summer heat.Pawod Cave 15

One of the dangers associated with diving in this overhead environment is that the bottom is blanketed with thick, muddy silt. Anybody untrained in maintaining perfect buoyancy and proper line laying is assured of a disastrous outcome once he has reduced the clear visibility to zero with a careless sweep of his fin or hand. Without a guideline and unable to return to the exit point, the unlucky diver will frantically move around in circles until his gas is consumed. With lungs burning for air and clawing desperately at the cave ceiling in his final attempt to survive, the diver soon succumbs to the dark and cold embrace of the cave.

After which, the locals would say that the diver was victimized by the “Mantaga”, a “freshwater octopus” that supposedly lives inside the cave.

We were not leaving anything to chance that day. Since the start of the course, we have been using twin 11 liter tanks with isolator manifolds. Each diver carried 3 lights. The main light is a High Intensity Discharge (HID) light. With a price tag of US $800, it is well worth the investment since its beam slices through the dark corners of the cave, turning night into day.

Using the reel properly is one basic skill a cave diver learns. We had 3 reels each. There was a main reel plus two spools. In our pockets, we carried directional markers and an extra mask. On our harness, we had line cutters and scissors incase of line entanglements.

L-R: Jean-Marc, Paul, Bernil. Suiting up beside the Agus Road.

We never fail to draw a crowd anytime we start gearing up at the side of the road that runs beside the cave. That day was not an exception. “Are you looking for the Japanese gold, Sir?” is a pretty standard question. The local kids whisper among themselves, I hear the word “Mantaga” mentioned. I caution them not to follow us when we swim into the cave’s entrance.

My technical cave instructor, Paul Neilsen in his tropical drysuit, making his way down to the spring…

With twin tanks on our back, it is quite an effort going down the rocky slope that leads to the cave’s pool. At the shallows, we settle down into rechecking our equipments and going into our safety drills. Valve shutdowns and long-hose drills are done before each dive.

During the briefing, it was decided that Paul would lead me into Paul’s Peril while I video the whole process. Lights on, wings deflated, we descended into the pool’s bottom. The water was murky from the silt stirred up by the numerous kids jumping around the water. A small school of guppies flitted around us. Paul finned into the cave entrance and I flicked on the video.

Paul making his way through the dark cave…

The entrance to the main chamber is like a gaping mouth.  Around 2.5 meters wide, and 9 meters long, the edges taper off to a restrictive size. A long wooden branch lies right at the center (God knows how it got there), and that’s where we did our primary tie-offs.

Inside the cave, the water is very clear. There seemed to be a constant flow in the area since the silt we stirred up from an earlier dive has dissipated already. Moving away from the cave’s mouth, ambient light diminishes, total darkness descends, and we hold it at bay with our powerful HID lights. Average depth of this area is 6 meters.

Think of a woman’s birth canal. There’s the entrance and then there’s the uterus. A big uterus—that would be the cave’s main chamber.

The bottom of this chamber is covered with slabs of limestone rocks that looked liked they were once part of the ceiling. There is a big pile of these rocks right in the center of the chamber. We’ve navigated around this pile on previous dives, carefully laying lines for reference.

With each exhaled breath, our bubbles disturbed the limestone ceiling and white particles drifted down like snow.

Each fin movement is a conscious effort not to disturb the silt. Everything on the bottom is covered in silt, thick brown silt that lets loose at the slightest movement. Left undisturbed, one can observe small tractor-like prints made by petite crabs.

After 8 minutes of careful movement across the chamber, the guideline leads us to the corner where Paul’s Peril starts.

Into Paul’s Peril

Imagine going inside a box.  Imagine the bottom of the box littered with rocks, mud, sand and silt. Imagine the ceiling of the box decorated with scraggy limestone. Imagine the box stretching far into a distance where your light does not fully reach.

Can you see all of this in your mind? Congratulations, you are in Paul’s Peril.

I focused all my energy into maintaining perfect buoyancy. “Don’t hit the ceiling, don’t scrape the bottom,” was the mantra that flowed though my mind. Certain stretches of the tunnel made it impossible for me to follow my mantra.

There was an area that left me chest deep in mud. My manifold was scraping the ceiling and each exhalation brought down so much particulate. Using my left hand, I slowly clawed my way forward. That action, together with my fining and breathing, created a total whiteout. Visibility turned to a finger length. All I could see was the white line on the mud floor that leads farther into the cave.

“What was Paul thinking when he laid this line,” was all I could think of.

What sort of person would wedge himself into a hole with no assurance that the ceiling will not collapse, or that the tunnel will not taper off after a considerable distance giving him absolutely no chance of making a 180 degree turn?

Having freed myself from that space, I found myself in a slightly bigger area where I was able to rise a meter off the bottom. I checked my depth gauge, it read 12 meters.

I could see the faint glow of Paul’s light in the distance. “Onwards then,” I shrugged.

Squeezing into another tight area, my eye caught the familiar shape of a giant clam’s shell.

“How many millions of years has this thing lain in here,” I wondered. It was at that moment that I felt what explorers might feel when they chance upon a discovery few people have ever seen. I felt awed by it all.

I continued on and came out into a chamber. The water in here was the color of deep blue—clear and clean. I took off my regulator and tasted it. Fresh water. Depth gauge reading, 15 meters.

The line continued in between two boulders. I followed it and I entered the final chamber of the tunnel. The line ended there and it was tied up on a rock at the bottom. Depth was 18 meters.

The bottom of this last chamber is covered in boulders. The sides are limestone and the area is big enough for three divers to float beside each other. I approximate that the space is around 3 meters by 3.5 meters.

Paul signaled me the OK sign, I responded and then he headed back out. Alone, I paused for a moment to enjoy the area.

Heading Back

The trip heading back out was something. The muddy silt we disturbed had amassed into angry, thick clouds. I kept my eye trained on the line for reference.

Then I came upon an area where the bottom sharply angles up. I got stuck. I moved left—scraped my manifold. I moved right—ouch, bumped my head on the ceiling.

And right in the middle of this silt-out situation, my HID light went off!

Good thing that the video light was still on. But then the monkeys in my head started chattering, “You’re stuck, you’re going to die, you can’t get out now!” Weird.

So I stopped, took a slow, deep breath, paused, exhaled very slowly and willed myself to relax. Then I slowly clawed my way out.

At the end of it, I saw a light. It was Paul waiting for me at the cave’s main chamber.

We gave each other the OK sign, shook hands, and then we swam out to daylight.

“Cool dive,” I thought.

– Bernil 2007

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