By: Jonathan Bernot
I recently had an instructor tell me he wants his students to perform a check in class that they will actually continue to do throughout their cave diving career and that the traditional S Drill is antiquated and no one will continue to do it so why teach it as such. I believe this is a false idea and that there are two problems and scenarios that need to be addressed. One is the S Drill as a training tool, and the second is the S Drill as a predive method of ensuring the long hose is free and all regulators perform properly. Let us look at both of these goals and how they can be executed during class and be used, or not, throughout a divers career. Let us also look at some of the things that go contrary to the goals of these skills that are common place in the technical dive industry.
S-Drill as a Training Tool
“If this were a full cave level class I would get out of the water”. This is an actual quote I heard and while it sounded harsh it was true. It was the first time I really took to heart that there is a level of proficiency expected of a diver at a certain level in terms of buoyancy, task loading, and propulsion. The point was that at the upper level a diver should be solid in fundamental skills. Granted these are skills fine-tuned and perfected along the path to that upper level. A technical diver should be able to hover, without drastic variation in depth, maintain trim (many don’t even know what true trim is), maintain position in the water via finer finning techniques and motor functions, and while doing all of this perform a task. This is what the S-Drill helps to instill, teach, and test. If a diver cannot maintain position without going up or down by more than 2 feet and perform a task in the confines of two body lengths (divers head to head facing each other) then they will never be able to gas share or perform other functions in a tunnel or room (in the case of a wreck) that is 5-foot-tall by 12 foot wide. Not a tiny space in the grand scheme of things. All skills should be performed in open water prior to being performed in the overhead. This S-Drill as a training tool is the open water skill performance review prior to having a team share gas in the overhead. If they cannot maintain their buoyancy and position in open water, then when this is performed in the overhead, the odds of it going well are not good. I do not expect a dive team to perform an S-Drill like this before EVERY dive after class. They should practice it periodically with their regular team members on a schedule that will allow them to remain proficient. There are cases where this cannot easily be performed in open water. Perhaps that means those caves are not appropriate training sites for cave class. Does the site add training value? This is something we should ask ourselves as instructors. Will this skill make my students a better diver? Am I as a diver truly proficient in my basic skillsets? The S-Drill for teaching is so much more than just sharing gas. It is a task loading scenario. It is a team building and communications scenario. I once found myself glossing over this skill because many of my mentors glossed over this skill. It is time consuming. Especially when you have students that can’t do it proficiently. Sometimes that means we never even make it in the overhead on the first dive. That is fine. We are here to learn and as students and instructors we need to be able to separate training dives from experience dives. The end goal in my classes is for a team of divers to be able to safely execute a dive together at the level of their certification. The training and skills intensive dives should lead up to this. These training dives should be challenging and the course rewarding. The training dives may not be “fun” for the instructor especially. They should be productive and rewarding and through this at the end there should be a level of satisfaction and enjoyment gained by the students and satisfaction and reward gained by the instructor in seeing their students succeed.
S-Drills As Equipment Checks
The second type of S Drill and the second reason for performing them is as part of an equipment check. Anyone who says technical divers don’t like to pick at gear configurations and deficiencies has never gotten on an online forum or Facebook page. Unfortunately, this type of mentality gets out of hand in some cases but like most others I do take note of deficiencies. Here are some of the common things I see in tech diver articles and pictures and the problems associated with them.
Rich on the Right
High oxygen decompression cylinders being staged on the right side of the diver is a common problem for several key reasons. The first is that when deployed, the hose from that bottle does not route well around the divers neck. Therefore, if they must drop the regulator it becomes an instant dangling entanglement hazard and is also generally not as comfortable to breathe from. When scootering, and yes this is a natural progression in many cave and wreck careers, that bottle catches much of the prop wash on the right side thus creating significant unneeded drag. The most serious though, and the one as it relates to the S drill and long hose, is that when attached that stage on the right side most likely has trapped the long hose and will prevent its immediate deployment. This is a true safety issue.
Dry suit Hose
The number of dry suit hoses I see clipped in over a long hose is significant. It is easy to remedy but when I see this is says two things. One is that the diver clipped in his dry suit hose last, which is probably not the ideal scenario, and two no S Drill was performed otherwise this entanglement would have been discovered.
Inability to Reach the Long Hose
This is most often seen on rebreather divers where the diver has opted to stow the long hose on their bailout bottle. I often see that the long hose is dangling below the diver having been accidently pulled from hose retainers. This will lead the diver to reaching to the bottle only to discover no second stage is available having previously been pulled free. The second thing that I see which is quite common, is to prevent the previous scenario by stowing the second stage tight on top of the cylinder. Unfortunately this limits the ability of the diver to immediately be able to reach and deploy the regulator. There does come a point of too much streamlining where it impedes more important abilities critical to life support.
Long Hose with Inline Shutoff Engaged
A very common scenario is for divers to incorporate an inline shutoff on regulators not in use. This is particularly common in CCR divers however for some reason I am seeing them pop up on side mount open circuit divers as well. This is very problematic. I do not believe in hypotheticals and as such a case study is in order. A local cave instructor was diving with two other exploration team members when he experienced a catastrophic failure of his SCR manifold. Due to incompatibility issues with fittings (all from the same company) he was unable to secure gas from his system. When a team member donated his long hose, it failed to function. The OOG Diver then went and checked the valve of the donating diver. Only after inhaling water via inversion of the mushroom valve on the second stage (clearly near drowning) did he realize there was an line shutoff on the regulator. Any regulator that may be needed in an emergency should be unencumbered and capable of immediate gas delivery.
In short there are a great many things than can inhibit the flow of gas or the ability to donate gas in an emergency. The S-Drill as a daily ritual is crucial and can be modified to be performed at the surface while still checking all the required pieces. Unfortunately, when this is taught exclusively as a surface skill the actual sharing of gas while maintaining buoyancy and position is often a lacking ability. Sharing gas is not a thing of the past. With the advent of side mount and rebreathers I am hearing more and more people tell the public and their students it is an unrealistic scenario since they are self-sufficient. While those divers should never have to perform a gas share it continues to be a routine performed, and never expected. In all but one of the 5 real life scenarios where I personally knew the divers involved the diver who spontaneously asked for gas was not out of gas. They panicked during gas switches, failed to maintain sidemount bottle gas management, or thought they had bad gas when in fact they CO2ed themselves swimming too fast. In those 4 cases the divers involved were sidemount or CCR divers. In the 5th case the diver was a long time technical diver and cave diver who failed to maintain proper reserves on a technical wreck dive in doubles, ran out of gas, and had to share gas with his team member. Obviously, this scenario is problematic on many levels, however the reasons do not matter to the donating diver. They must now perform in order for the team to survive. The S-Drill set’s them up to be able to do so.
To close, it is certain there are two reasons to perform S Drills and two ways to perform them. The first, a neutral S Drill, hovering, maintaining buoyancy and sharing gas teaches team work, task loading, and reinforces buoyancy. It ALSO checks that all regulators are functional and the long hose is deployable. It meets both requirements. The second, modified S Drill checks that all equipment is functional. It is a more appropriate method of preparing for a dive by existing team members after class.