March, 2017
Are diving doubles and sidemount the same thing?
In terms of the number of tanks you might carry, sure, doubles and sidemount appear similar.
However, sidemount and backmount doubles differ in one crucial area – the isolator manifold!
Why would you ever need more than one tank?
Now, let’s start from first principles.
What are the reasons for carrying more than one tank in the first place?
Some might argue that gas volume is the primary reason, however, redundancy is a more important and valid reason.
On a normal single tank (especially one with yoke valves), O-ring failures (tank neck, tank knob and yoke valve) are relatively common.
The next most common thing to fail in scuba gear would be the regulator setup, as there are many O-rings and hoses that can rupture and cause a catastrophic gas loss.
Single points of failure are dangerous when diving
With single tanks, a gas loss from an o-ring failure in the yoke valve or the regulator will result in an immediate out of gas situation.
In order to deal with this situation in deeper or more extreme dives where a direct ascent to the surface is impossible (a decompression obligation or an overhead environment), we would require a secondary gas supply so that we don’t go into an out-of-gas situation on a single failure.
Double your tanks, double your hoses, double your failures
A quick solution to this was to just carry another tank.
In the early days, people would just carry 2 tanks, with a full set of regulators on each, in essence, doubling up on the gas supply, but also doubling up on the failure points in the system.
However, what if halfway through the dive, you had one full tank and one nearly empty tank and a failure happened on the full tank?
This would leave you with a nearly empty tank, with no backup.
Clearly, this wasn’t an ideal solution.
What about connecting these tanks?
The best solution to this was connecting the tanks with an isolator manifold.
Two 300 bar scuba cylinders connected by an isolating manifold
Using this setup, we could have a single regulator failure but still have access to all of our gas supply.
The isolator is an important part of this setup because it would allow a diver to isolate an unfixable leak to just one tank.
This prevents an immediate out-of-gas situation because you would still have one regulator working.
Some might argue that the manifold itself presents a failure point, but in all my years of diving doubles, I’ve not seen a bad manifold failure happen in the water.
In most cases, if the manifold were to fail, it would fail during the filling or setup process.
So what about sidemount?
So where does this leave us in the discussion on sidemount vs backmount?
Sidemount was created because of a specific need to access ever smaller and tighter holes in cave exploration. Places where backmounted tanks would have limited access.
Diving sidemount in open water negates the benefits of carrying 2 tanks by reverting to the original idea of the independent doubles. This of course comes with the associated negatives mentioned above.
There are some benefits to diving sidemount that proponents argue on; that it’s easier to put on; easier logistically; better for the back, etc.
See my other article about diving sidemount in open water to get an idea of why I think that’s not so relevant.
However, when we come back to the main reasons of why we have multiple tanks, sidemount just doesn’t match backmount when it comes to redundancy.
Should I set up my own gear or trust the resort to do it for me?
Sadly, the current state of the South East Asian dive industry has devolved into operators who pander to their divers every need. Setting up equipment before the dives, changing tanks between dives, and even putting on fins for their customers.
Some divers have come to expect this level of ‘service’ and being spoilt with this lazy way of diving, have forgotten completely how to set their gear up themselves.
I am personally against this, and will not allow it in the operations that we have. It’s not that we can’t do it, but a matter of principle.
Who’s really responsible for your safety?
If divers can’t take personal responsibility for their own safety, then who is really at fault when an incident occurs?
The scuba equipment that we use is critical to keeping us alive underwater. If we don’t even understand how it works, then if and when something does happen underwater, does that diver know how to react and how to deal with that situation?
Should we be faulting the operations at which these incidents occur?
Or should we be faulting their Open Water instructors for not training these divers well?
Or is it the diver, who gets complacent and fails to check their equipment prior to getting in the water?
The practice of signing liability forms and waiver forms before any dive doesn’t negate the responsibility that operators have in keeping divers safe.
However, when we continue to produce divers who can’t even remember how to set up their gear, who is really at fault?
Blame, blame, everywhere blame
This is a chicken and egg situation, and I’m afraid passing the blame from one party to another is not going to change anything.
Ultimately, individual divers should and must have responsibility for their own safety.
Dive operators are there to provide the logistics for diving, and to provide a safety briefing of the common local conditions found at that location.
Divers should take primary responsibility for their own safety, and not rely entirely on a dive guide or Divemaster.
If a dive is risky, or uncertain, divers should not be afraid to speak up and ask questions, rather than just trust that everything is under control and follow blindly.
It’s not just about setting up equipment, is it?
I know this question is about equipment setup, and maybe some people will think that it’s not a big deal, but to be honest, I think it’s not just about equipment setup. This leads to other skills and knowledge that most divers take for granted.
Personally, I do think that this is symptomatic of a larger problem in the diving industry.
As individual divers, always look to get better training, even if you think you already have the relevant certification, as no two dives are ever the same.
We never know what Mother Nature is ready to serve up to us, so all we can do is to be as prepared as we can be.
How is the GUE Fundamentals course different from the PADI Advanced course?
The difference between the Fundamentals course and the Advanced course is really about the curriculum and comprehensiveness of the courses.
The Advanced course offers the new diver a chance to experience 5 other types of diving environments and covers those in a relatively quick format.
The Fundamentals course instead focuses on an individual and team’s dive skills, in order to manage these new environments effectively.
Diving and Driving, an analogy that keeps on going
The Open Water course is like the basic driving course that everybody does in order to get a driving license. It covers basic techniques, such as accelerating smoothly (propulsion kicks), parking (hovering), braking (ascending smoothly to the surface) and signaling (communication).
The Advanced course would be like getting experience driving on real roads, in real conditions. For example, driving at night (night dives), at high speed on expressways (drift dives), tight car parking spaces (peak performance buoyancy), and trying to navigate while driving in another country (navigation dives).
The Fundamentals course would be more like a defensive driving course, where you’d learn how to minimize your risk (awareness and teamwork), perform pre-trip inspections (gas management, dive planning, decompression management), and handling skids, accidents, and hazards (emergency drills).
Investing in yourself is never a bad decision
While the Fundamentals course and the PADI OW and AOW are different in terms of how they approach diver training, both are absolutely necessary for any serious diver’s training log.
Only after the basics are learned, can a higher level of skill be developed.
Personally, I would always recommend investing in yourself by taking the Fundamentals course, as it takes a more detailed and focused instruction in order to attain a higher level of skill.
I do believe that both types of courses serve their purpose well, but if you truly want to be a serious diver, then the Fundamentals course is the best place to get started.