What is...
Technical Diving?
Technical divers are those unique individuals who go beyond recreational diving limits.
- Past 130'
- Overhead environments
- Mandatory decompression obligations
To safely make these dives, technical divers have special training and use special equipment. Technical divers are patient, painstaking, methodical, and detail-oriented. Technical divers often use redundant equipment for items that are critical to survival or the mission. We say, "Two is one, and one is none."
Technical divers are the "best of the best." Before you you make technical dives on your own, I will make sure you know your stuff!
Equipment
Equipment for technical diving differs a good bit from equipment for recreational diving. Technical divers like simple gear that's easy to use and maintain, which is good because we use a LOT of gear!
What kind of technical diving do you want to do?
Open Circuit?
Closed Circuit?
Backmount?
Sidemount?
I can teach several different configurations, so let's explore the options.
Open Circuit vs.
Closed Circuit
Here are some pros and cons I thought of when considering whether to use open circuit or closed circuit for technical diving
|
Open Circuit |
Closed Circuit |
Advantage |
|
Ubiquitous – gear is everywhere. Adequate repairs widely available |
Rare – CCR divers are somewhat rare. Expertise is system-specific |
OC |
|
Gear support in vacation destinations is good |
Gear support in vacation destinations is spotty |
OC |
|
Relatively cheap gear cost |
Relatively expensive gear cost |
OC |
|
Relatively expensive gas cost for deeper dives |
Relatively cheap gas cost for deeper dives |
CC |
|
Noisy |
Quiet |
CC |
|
Gas is cold |
Gas is warm |
CC |
|
Diving is simple-ish |
Diving is more complex |
OC |
|
Dives are gas-limited to an hour or so |
Dives can be 4-5 hours long |
CC |
Based on the considerations in the table above, the ideal situation would be to be trained to an equivalent level in both open circuit and closed circuit. Given the time and expense involved, a reasonable compromise would be to get open-circuit technical diving training to the Tec 50 level, and then start rebreather training. This combination has the advantages listed below.
· Could still do tech dives in areas where rebreather support is non-existent or prohibitively expensive.
· Would enter rebreather training with a reasonable skill set and knowledge base for technical diving.
o Tech training would leverage current open circuit experience
o Rebreather training would then leverage technical experience
· If one were absolutely set against closed circuit, tech training could continue into deeper trimix courses, if interested.
· Regulators, tech computers, and deco cylinders would carry forward into rebreather diving. Main cylinders from open circuit tech may also carry forward for more advanced rebreather diving.
Sidemount vs. Backmount
|
Backmount |
Sidemount |
Advantage |
|
Steel doubles are easy to find, at least in the US |
Steel sidemount cylinders are harder to find outside the US |
None |
|
A set of doubles is heavy |
Allows handling a single cylinder at a time |
Sidemount |
|
Fixing a regulator problem is pretty close to impossible |
Fixing a regulator problem isn’t so tough |
Sidemount |
|
Doubles tend to roll the diver onto his back |
Trim is horizontal |
Sidemount |
|
Manifold failure can lead to catastrophic gas loss |
Catastrophic gas loss is nearly impossible in sidemount |
Sidemount |
|
Breathe from same second stage continuously until switch to deco gas |
Switch second stages every 300-500 PSI |
Backmount |
|
Very difficult to gear up in the water |
Very easy to gear up in the water |
Sidemount |
|
Bulky and not very streamlined |
Easier to negotiate through smaller spaces |
Sidemount |
Gear you need to get started
|
Backmount |
Sidemount |
CCR |
|
Double tanks, banded with isolator manifold. |
Two tanks, sidemount rigged. Requires per tank stainless buckle cam band, 1 weight slide, four extra large bolt snaps, approximately 40” of paracord. Two elastic hose retainers on right tank, one on left tank. |
CCR system and one bailout tank. |
|
Two regulators for doubles. 7’ 2nd stage hose, and BCD inflator on right regulator. Shorter 2nd stage hose, pressure gauge, and drysuit inflator on left regulator. Recommend non-turreted. |
Two regulators for sidemount. 7’ 2nd stage hose, drysuit inflator and SPG with 6” hose on right side. 40” 2nd stage hose, BCD inflator, and SPG with 6” hose on left side |
One regulator and SPG, some additional hardware needed if tank is to be plugged into rebreather. |
|
Backplate, harness, and wing |
Sidemount BCD |
CCR usually comes with BCD. Recommend adding hardware for carrying bailout tanks sidemounted – butt plate & bungees |
|
Two ways to measure depth & time and to determine deco · Two depth gauges and bottom timers, plus two sets of dive tables · Multi-gas computer, plus depth gauge & bottom timer, and one set of dive tables · Two multi-gas computers, ideally identical |
||
|
Two cutting devices. Recommend knife or shears, and line cutter. |
||
|
Canister or wrist mounted light, plus backups |
||
|
Wrist slate or wet notes, and pencil |
||
|
Compass, clipped off, pocket, or wrist mount. Computer integrated compass OK, if student familiar with use. |
||
|
Lift bag or DSMB and finger spool with double-ender snap. Needs to be 50-100 lbs lift |
||
|
Dry suit, hood & gloves. |
||
|
Deco cylinders… One regulator, with 40” 2nd stage hose, SPG on 6” hose for each deco cylinder. Recommend AL40 for deco cylinder. · Tec 40 requires one deco cylinder · Tec 45 requires one deco cylinder · Tec 50 requires two deco cylinders · Tec 65 requires two or three deco cylinders · Tec Trimix requires three or four deco cylinders. |
||
|
Deco cylinder rigging is “standard” available commercially, or build your own. Two medium or large bolt snaps, carrying strap, one sheathed pipe clamp |
Deco cylinder rigging is “Loflin sidemount” rigging, requires, two large quick-links, two large bolt snaps, 36” of 5/16” bungee, one sheathed pipe clamp or cam band, two elastic hose retainers. |
Use “standard” rigging if not using sidemount for bailout. Use “Loflin sidemount” rigging if bailout is sidemounted. |
Start by taking classes that prepare you for technical diving.
Sidemount
Drysuit
Nitrox
Deep Diver