What it comes down to for me is a concept that I've been teaching in Tree Work safety for years: Always do things with "considered risk"
Simply put, everything we do contains some element of risk, whether it bet getting out of bed in the morning or solo free-diving under the ice at night. Whether we do them or not is determined by what we consider the risks to be and whether we find them acceptable or not.
For example nobody thinks twice about getting into their car and driving down the road yet the risk of injury or death is ever present. Most of us through training and practice have discovered the myriad risks, have learned to compensate for them whether through skill, planning, or decision making, and no longer give driving a second thought.
But the key is whether we "consider" them fully and analytically, and what actions we may take to mitigate those risks. We all know the fidiot that has no clue what they are doing or why and is one step away from disaster. And when it all goes wrong they have that stupefied look of "what the hell that happened!"
My employees and students are all familiar with the principle of not ever being surprised when something goes wrong. It is a mortal sin in my company for them to say, "I didn't think that would happen!"
It's a sin because it means they hadn't given due consideration to what they were about to do and its consequences including the risks. I've always told them I would much rather have them explain a failure/accident/near miss with, "I considered it a possibility but discounted it for these reasons..." even if their reasoning was flawed.
Yes, sometimes things do occur that we can't conceive or consider. These are usually due to the things we don't know that we don't know. Of course we cannot learn without going into that territory sometimes.
But by applying the concept of considered risk we reduce the number of such events or at least only venture into areas that are only somewhat unfamiliar. In that way we can still draw on what we considered to respond/recover and at least have some influence on the outcome rather than wholesale disaster.
So, for my solo-diving that's how I approach it, I consider the risk, mitigate it as best I can, and ask questions that help me discover what I don't know so I can then ask the right questions. I take it one step at a time and venture into each unknown in turn
I'm a very analytical person so the process by which I came to my dive "mission rules" and kit selection may be considered overkill, but it allows me to dive solo with confidence, and I believe, greater safety than if I were relying on a buddy.
So, here's my current solo-dive mission rules and kit based upon my considered risk analysis:
Mission Rules:
- No solo-dive in water deeper than 45 feet
- I have practiced and succeeded in doing an emergency ascent without freaking out from that depth
- End dive when planned, <750psi in tank, or after 120 minutes, whichever occurs first.
- These are my personal, arbitrary, limits
- Restrict total dive time per day based upon my known physical endurance
- <=15 feet max: 6 hours max
- >15 <20 feet: 4 hours max
- >20 feet: 2 hours max
- All events that have cost me dearly were preceded with a string of non-critical events. I've since adopted this 3-strike rule.
- One non-critical event/failure is typical, remain vigilant, continue dive as normal
- Two events is a warning from the cosmos to increase vigilance and prepare to abort/cancel dive with out notice.
- three events is the cosmos saying it is time to go home. Abort/cancel the dive immediately as safely as possible
- Non-critical event examples include
- injury in or out of water
- any single episode of controlled hyperventilation
- excessive difficulty donning gear
- forgotten/missing/dropped/lost gear
- frustration/irritation/crankiness
- Abort/Cancel dive for one or two events when coupled with a sense of forcing the dive or otherwise a feeling of "pushing a rope", especially before entering the water.
- End dive immediately when any of these are true:
- Use of redundant air system for any reason
- Failure of BC
- Loss of mask
- Loss of both computers
- three non-critical strikes (see above)
- sixth-sense/not feeling it
- forcing the dive or otherwise "pushing the rope"
- Any time a decision to "do JUST one more..."
Kit:
- Primary air system: Two color coded second stages with isolation valves.
- Redundant air system: One Second stage with isolation valve.
- Minimum 19cuft
- Tripled my average SAC to account for a panic situation
- Calculated the amount of air necessary at that SAC to do a normal ascent from 45 feet with a safety stop and then doubled it.
- All regulator brands/models consistent across primary and redundant air sources
- First stages, environmentally sealed Zeagle FH-VI (arbitrary choice)
- less likelihood of first stage freeze up (most water temps here in the <65*f)
- Second stages Zeagle ZX (arbitrary choice)
- Drysuit
- redundant buoyancy
- reduced physiological stress due to being wet and cold
- Positively Buoyant fins
- in case I have the dropsies
- AI Computer with electronic compass
- backup analog backup compass
- Redundant SPG/AI computer
- Cutting Tools: Shoulder mount ambidextrous release serrated knife with line hook, EMT shears in pocket.
- DD Flag
for myself. Thirty feet or less, the surface is my go to. If it is dark water and especially with real entanglement concerns then I will have my buddy bottle or IDs regardless of depth.
