Cave Diving, Cave Exploration and Cave Mapping in Yucatan, Mexico
Casa Cenote near Tulum Mexico

“Never Give Up, Don’t Waste Time Scribing Notes!” Advanced Side-Mount Cave Diving.

Putting regulators on the tanks, carrying them to the water’s edge, and slipping them into the water is almost a meditative experience. Every time I get the opportunity, it is another awaking.

In April, I spent three days working with Steve Bogaerts on the basic side-mount class. The class included: lecture, building a custom side-mount harness, and skills & drills. He focused on gear configuration, safety procedures, tank handling and diving in side-mount configuration. I am convinced that those three days evolved my gear configuration by at least 50+ dives of tuning and experimenting. He condensed years of practical experience exploring into a well thought out task specific system. At the end of class, I was tasked with learning to reverse frog kick, improve my line laying, and diving in side-mount. We agreed to meet in a month for Advanced Side-Mount Cave Diving Class.

My Advanced Side-Mount class was scheduled for May. By this time, I had executed 29 side-mount dives, nailed the reverse frog kick and improved my line throwing skills. I felt very comfortable in side-mount; I was ready to continue.

Class started with a lecture at Steve’s place. He covered:

  • Revised equipment list, tailored for diving in small passage.
  • The need to be able to remove and replace every piece of kit.
  • The recent fatality at Genie Springs, Steve is a local Safety Officer.
  • More conservative gas planning rules.
  • And discussion around knowing one’s limits, mental toughness and the things he has seen deep in the cave, such as abandoned equipment and erratically laid line. All evidence of people reaching their limit.

The revised equipment list included two new items for my Dive Rite Double Zip Pocket. He suggested that I carry a spare bungee to hang my tanks from in the event that I have to cut my normal side-mount bungee and a lanyard with a clip for no-mounting.

Steve is a hawk with regard to gas planning and management, which I suspect is why he is still alive and pushing. In previous training we talked about why the rule of thirds is not conservative enough here in Mexico. Locally, we have low flow caves that do not provide the benefit spitting you out. This was clearly demonstrated when Allie and I almost sucked my tanks dry during a drill in her full cave class. I surfaced with the gauge reading nearly zero after my safety stop.

For pushing challenging cave, the rule of thirds is not conservative. He suggests the rule of sixths or quarters. We discussed the actual usable volume in the tank, which I had never taken into account, and that we should factor that into our gas calculations. The point being, you can never finish a dive with too much gas. The conditions we will encounter include: zero visibility for extended periods, passing major restrictions in zero visibility, entanglements in zero visibility and equipment failures in zero visibility. Any one of these will delay your exit, take two and you’re going to be very glad you have plenty of gas. The extra volume will be a determining factor in your ability to stay calm, cool and collected. As you will read, I learned this lesson. We closed the lecture with an equipment workshop that lead to additional tweaks.

The first day’s diving was confined water skills at Ponderosa. I had the option to go to other sites, but Ponderosa is convenient to both of us. Be forewarned, I am not going to spoil the plot and reveal everything, just the highlights. To begin, every skill I performed I had to perform with visibility and without visibility. So, if I describe a skill, understand I did it at least twice.

The skills started off easy. I demonstrated my ability to swim with tanks on, one tank on and no tanks on. I needed to do this through restrictions. This culminated in having to pass a no-mount restriction in one direction with visibility and then pass it in reverse with no visibility. This was by far the tightest restriction I had ever negotiated. I had to breathe out to get through it. This is where the day got really interesting. I arrived at the restriction in zero visibility. I identified it and then backed up a couple of feet to prepare my gear. This included removing my right tank and butt-mounting it. As I did this, I forgot to clip the lower clip to off on the tank, so it “grabbed” the guideline. I figured this out quickly. I got the tanks into position while maintaining contact with the guideline. As I proceeded through the restriction, I was nervous because the first pass was really tight and I had to push myself through with my feet. It was a mental challenge. I made it through the restriction. I audibly celebrated and Steve heard me. My celebration was short lived.

Surprisingly, the line “came off” a large placement. I was left with ample slack line in the water. I didn’t realize there was slack line, so I started to replace my tanks. Almost immediately, I was entangled. Steve says he did nothing besides remove the placement. The entanglement was natural. As I swung my left tank back into place, I heard gas leaking. I thought, damn he is piling it on. Zero visibility, entangled and a leak.

My first stage was leaking from one of the LP hoses. This was a real equipment failure, must have been Murphy and his love of cave divers. I turned off the left tank and went on the right tank. I decided deal with one problem at a time, the entanglement. I couldn’t see working an entanglement and feathering the valve. This is where practice and a methodical approach really count.

I started to work out how I was entangled. I tried to untangle myself but it seemed hopeless. In retrospect, I should have spent another four or five minutes working the tangle and the slack line. If I were patient and removed some of my gear, I could have gotten through it. But at the time, the only option was to cut the line. When I was sure I was on the exit side with the line wrapped around my hand, I removed my Z-knife and cut the line. Ping! The other end was gone. I put a loop in the line and looked for a spot to secure it. I couldn’t find one immediately, so I move with the line and finned. Later, I found out that the fining blew the other end of the line away from me. I my search for a spot to secure the line, I realized I was on the cave side of the line. I smacked my head and grumbled to myself. Steve later told me that I had rotated through 180 degrees prior to cutting the line. I was disoriented and didn’t realize it.

Steve hovered watching with amazement. He told me that he really enjoyed watching; he couldn’t have planned it any better. It was the real deal, all natural in the course of a dive. It was a lesson I could never have planned.

I am on the cave side of the severed guideline with a leaky regulator. I thought, “This really sucks.” I collected myself, deployed my safety spool and attached it to the guide line. I started my search for the guide line, making another mistake; I neglected securing prior initiating my search. So after a minute or two, I returned and secured the line properly near the exit of the restriction. I knew approximately which direction the next tie off was from the exit of the restriction. I did a very methodical search and after 25 minutes, I found the errant end of the line. If you have spent anytime at Ponderosa, you can image how difficult this task is with the pond weed and the rocks. The restriction and the tie off are about 15 feet apart and I was looking for the loose end of a cave line in pond weed.

At one point in the drill, I briefly considered quitting. Twenty five minutes is a long time and I started to feel hopeless. However, I remembered something I had read, “Never giving up and don’t waste time scribing notes, just keep going till it is over.” I knew for a second why people surrender and are found lifeless with gas in their tanks.

With the line in hand, I had to connect my safety spool to close the gap. This is when I discovered that I had too much line on the spool for it to be useful. I was already under a lot stress, and then I had to fight with my spool to get it clipped off. Once it was clipped off, I chose to leave the spool inline, instead of making a proper repair. I wasn’t sure how long it had been or how much gas I had left. My tank was getting very light. Later I learned this was a mistake. If I had another entanglement, broken guideline or missing jump spool, I would have been without the piece of gear I needed most. Steve suggested that I make every reasonable effort to take my safety spool.

After I passed the next restriction, I switched to the leaky tank and feathered it all the way home. The drill was a HUGE success. I learned some huge lessons:

  • Be on the right side of the guideline when you cut it. Seems obvious, right?
  • If you can, hold onto both ends of the line.
  • Have plenty of gas. You may have to do a lost line drill with only one cylinder available.
  • Failures never come alone. Gotta love Murphy.
  • The only option at this level is calm cool persistence. If you don’t have it, do not proceed.

The most difficult skill I had to master was to swap regulators between tanks underwater. This is a three part drill: breath from a free flowing regulator while feathering it, breath from a tank valve underwater and perform the regulator swap.

This was a very difficult set of skills for me to master. My breath holding ability is weak, less then one minute. And this decreases as the CO2 builds up. This skill took me 5 attempts over two days before I was able to get through it in zero visibility. One attempt I had to ask for a regulator from another tank. One attempt I ended up bolting to the surface because I panicked a little, which is exactly what we are trying to train out.

I have been tasked with practicing this set of skills till I have it nailed. Steve also suggested I seek some apnea training to increase my breath holding skills. We agreed 2-3 minutes is a reasonable goal and will provide ample time.

The class included two cave dives. The skill was to complete the dives. We did two dives down stream at Grand Cenote. This was a pleasure. The benefit of going downstream is you are the only team in that part of the system. There wasn’t a single hand print or fin slash. The system is in great shape. The two dives included a handful of major restrictions that required passing with a single tank and a high flow major restriction. We turned the second dive when we got to a silty no-mount restriction. We were nearing our turn pressure. I have to admit, the cave diving was a relief compared to the skills in confined water.

Steve video taped me during the dives. We reviewed the video and talked about: my strengths, my blunders and bad habits.

My homework for stage/multi-stage side-mount class next month is:

  • Become more aware of my tank position. I am letting them get too high on my body.
  • Work on my frog kick. I am doing half a frog kick with just my ankles. I am wasting a lot of energy.
  • Work on my kick selection. I am capable of doing all the kicks, I just don’t always chose the best one. I frog kick when I shouldn’t.
  • Work on my apnea skills.
  • Work on my ability to breath from the tank and swap regulators.

After reflecting on class and the skills practiced, I am convinced that training at this level is as much about mental toughness and learning personal limits and capacity as it is about learning specific skills. By this time, one must possess excellent watermanship, commitment, confidence and dexterity as a prerequisite. You shouldn’t be learning these at this level; they need to be in muscle memory. The drills we executed and the dives we performed provided the grounds for me to hone my mental toughness, assess my limits, and determine my ability to function effectively as the failures pile up.


1 Bill Ripley { 05.20.08 at 8:04 am }


Thanks for sharing your report with me. You write well, as I felt like I was there with you during your drills and frustrations. Quite a course and instructor – Congratulations.

Are you going to SM with your Meg?


Bill Ripley

2 Hans { 05.20.08 at 9:45 am }


Good to hear from you. I have been watching you post over on Rebreather World and you raise some good issues.

I am not considering side-mounting my Meg right now. I was really hot for the idea before I started to actually side-mount, however I am not that sure about the idea anymore.

I am going to wait on the current crop of side-mounted Megs to mature. I know Rob Infante is getting his unit converted and a couple of other guys in NJ have done it. I would like to dive one before I commit to it or considered it further.

The other issue is the rarity that I dive my Meg. I only dive it on dives deeper then 50-60feet, which is once every couple of weeks. I have two reasons: cost and logistics.

It costs $8.00 to dive two AL80’s. It costs about $23.00 to get my unit all charged up and ready to dive, plus the wear and tear.

Diving my Meg takes at least an hour to setup and break down at the apartment. Diving open circuit takes less then 5 minutes, I grab the basket of gear throw it in the truck and that is it. No tests, no logging, no packing a scrubber.

Since I am diving 4 days a week, this can really add up.

I suspect that when the diving requires me to side-mount my Meg, it will be clear and I will make the switch. In the mean time, I am diving mostly OC.

Are you side-mounting your Meg? You coming to Mexico any time soon?

3 Shirley { 05.20.08 at 9:50 am }

Excellent write-up. I’m adding Steve’s class to my to-do list! Thanks for sharing.

4 Bill Ripley { 05.20.08 at 9:59 am }


Switched to a Hammerhead several months ago. While I do use a sidemount butplate for bailouts in caves (still attach at harness in the ocean), I’m still diving the usual rig setup. Glad you’re getting so wet. Be safe.



5 Hans { 05.20.08 at 10:09 am }

Bill, how come you clip your tanks to the waist strap in the ocean?

Shirley, Thanks for commenting! Steve is an excellent instructor and all around good guy to spend time with. If you want to learn more about his services here is Steve Bogearts’ Website.

If you have any questions about the classes Allie or I took, let me know.


6 Bill Ripley { 05.20.08 at 10:22 am }


I find it easier to attach bottles to harness, stand up, walk to edge of boat and jump in. While I might switch to buttplate at bottom, will usually switch back to harness before leaving bottom. It makes it easier to get back on the boat and/or to hand off to crew. Caving, of course, gives you the time to rig while in the water. No question that it is easier (for me) to swim with BO tanks with the buttplate setup.


7 Lynne { 05.21.08 at 12:55 am }

I enjoyed your account. It’s amazing how the caves will throw you even more things to handle than your instructor could plan, isn’t it? Your story of the lost line search reminded me of mine two weeks ago. Danny’s summation of the drill was, “You WILL find the line, if you keep looking. Whether you will find it with enough gas to exit or not is another question, but if you keep looking, you will find it, and the line is your way home.”

I had the good fortune to meet and have dinner with Steve while we were down there. He seems like a very good guy, and he had lots of good stories to tell.

8 Hans { 05.21.08 at 9:22 am }


Thanks for the comment. I agree with Danny, though convincing yourself you will find the line can be an mental challenge. I guess that is why thirds is just not conservative enough when you are diving in low flow or difficult cave.

Steve told me a story that involved an entanglement that required 25 minutes to extricate himself. He ended up removing just about every piece of gear, short of his fins. He was going to cut the line at first, but then decided to methodically untangle himself instead of risking loosing the guideline. With enough gas, this is a reasonable solution, with out it, it will become very stressful. Ug.

Steve is certainly full of stories.


9 John K { 05.22.08 at 10:22 pm }

Always enjoy reading you post. I very impressed with what Steve seems to be teaching you. I would not mind taking that Apnea class with you. Let me know how you go about arranging it.

Just got back form doing some cave and wreck dives in FL.


10 Hans { 05.22.08 at 11:41 pm }

I was told there is a dive shop in Xpu Ha that advertised apnea training. I have traveling too much in the last two weeks to really follow-up.

If I get any additional information, I will pass it on.


11 Ross { 05.25.08 at 12:54 pm }

Hey Hans , Just stumbled across your sight when looking for tips regarding a sidemount helmet .
Iv also been to mega and seems asif they only have the (upgraded version, A pack wigh knee and elbow pads)

There is deffinately alot i can learn from articals you wrote and more so from Diving together . Thanks a mill for letting me tag along .
Tajma-ha next hey big guy .

Ill call you this week so we can sneak off .

12 John K { 05.25.08 at 8:09 pm }

I think your reports have convinced me that I need to come down and take a sidemount course from Steve.

13 Hans { 05.25.08 at 8:53 pm }

Ross, if there are no helmets at Mega try the Manzania on 40th Ave and Jaurez. It is the big yellow store.

Patrick and Nanado have construction helmets that they converted. They are not as simple as the purple helmet of death, but still useful to get you going.

I think the work helmets sell for $250.00. You will need to do a bunch of cutting and grinding on the work helmets but they seem to come out ok.

I look forward to making an afternoon run to Taj also. Can’t wait to do some real side-mounting.


14 Hans { 05.25.08 at 8:57 pm }

John, your the third person who has told me that. With any luck, Steve is reading this and I will get my referral fees. 😉

Actually, there are no referral fees, just solid training and practice experience. It is worth while just to spend time with him training, training anything. I learned a ton while shadowing Allie’s full cave and I have learned a ton just sitting at dinner with him.

I am glad to have him as one of my teachers. I feel lucky to have the opportunity.


15 Sebastian (Blonde Mexican) { 05.26.09 at 7:49 pm }


i really like how you write, it very good fro motivation.
I was thinking about make my Adv. SM Course, i already have a few dive on my SM Razor Harness, and i fell great!
Also i already try to pass trow the Pick Pocket Restrictions and the Molar Restrictions at Sac Actun Sistem, (Gran Cenote “downstream”) and the where “Nasty” jajajajajjaja

Hope one of this days you can keep shearin g you knoledge with me with a cave dive!!!

take care!!!!!!

16 Hans { 05.26.09 at 9:11 pm }

Sebastian, I am sure I will be back in town. Continuing education is essential especially as you get into some of the nastier cave. There are some skills we just don’t consider practicing until an instructors or a mentor drives us to them. I know I learn a ton and it served me regularly. It also accelerated my ability to assimilate new skills and use them in my daily diving activities.

The objective is to become an old and very experienced cave diver. To become old, I need to not die . Therefore, I need to have the skills to make good decisions about how to handle difficult situations with a “mind like water” mentality.

Keep practicing and take your time. There should be no rush into tiny cave. The risk doesn’t increase in a nice linear way. It increases at a radical rate.

See you soon and say, “Hi” to everyone!