Technical Diving Courses in Rarotonga

Tech diving training in the Cook Islands

Tech what? What is technical diving?

Technical diving or tec diving is scuba diving beyond the limits and boundaries of normal recreational diving. However, the differentiation between technical diving and recreational diving is a bit misleading as most tec divers dive mainly for recreation.
The difference is technical diving requires more experience, more complex dive planning and more specialized dive equipment. For instance, technical divers often use gas mixtures that differ from normal air or recreational nitrox mixes, as well as using multiple gas sources. Technical diving requires considerably more advanced diver training than recreational diving.

Diving beyond recreational limits

There is no universally agreed definition of what technical diving is. Above all, different dive training agencies have different definitions. Furthermore, even training agencies with similar definitions may differ when looking at the precise boundaries of technical and recreational diving.

As an example, PADI, the largest recreational dive training organization defines technical diving as: “diving other than conventional commercial or recreational diving that takes divers beyond recreational diving limits”.
It is further defined as an activity that includes one or more of the following:

  • Diving beyond 40 meters/ 130 feet
  • Dives requiring stage decompression
  • Diving in an overhead environment beyond 40 meters/ 130 linear feet from the surface
  • Dives with accelerated stage decompression
  • Use of multiple gas mixtures in a single dive

Is technical diving safe?

Tech diving is a means to an end. In other words, the diver needs the training and equipment to do the dive. For instance, a recreational diver who wants to safely explore a deep wall, shipwreck or cave has no option but to gain more dive experience and continue dive training, using tons of equipment. Because of the complexity of the dive, the diver must accept that the dive involves a higher risk for injury or death compared to a recreational dive. However, with the right training and equipment, the technical diver can safely go to places where recreational divers cannot go.

Open Circuit (OC) vs. Closed Circuit (CC)

In technical diving you often hear the terms Open Circuit and Closed Circuit.

Open Circuit (OC) refers to an ordinary scuba regulator first and second stage attached to a cylinder. Correspondingly, this is what 99% of all divers use. The diver inhales gas from the cylinder and exhales into the open water. Hence the name Open Circuit.

In a Closed Circuit diving system, the exhaled gas gets recycled and stays in the system or “loop”. Closed Circuit diving systems are called rebreathers. In the heart of every rebreather is a scrubber, where the carbon dioxide in the expired gas gets removed or “scrubbed”. Generally speaking, there are two types of rebreathers: Semi-Closed Circuit Rebreathers (SCR) and Closed Circuit Rebreathers (CCR).

Semi-Closed Circuit Rebreather (SCR)

A Semi-Closed Circuit Rebreather releases some of the expired gas into the water with every fourth or fifth breath, therefore the name “Semi-Closed”. SCR’s use a single enriched air cylinder and are easy to operate. Even though they are more complex than OC, SCR’s are mainly used within the boundaries of recreational diving.

Closed Circuit Rebreather (CCR)

In a Closed Circuit Rebreather, no gas is being released into the water unless you ascent. Therefore, CCR’s are great for underwater photographers or videographers as you don’t make any bubbles. Because they don’t release any gas into the water, CCR’s are also more efficient than SCR’s. A CCR uses two cylinders: one with pure oxygen and one with a diluent gas. Because Closed Circuit Rebreathers are more technical in their operation they require more complex training.

CCR advantages
OC Scuba advantages
  • Optimum nitrox mix throughout entire dive
  • Increased no-decompression limits
  • Decreased decompression obligations
  • Only one mix required for deep mixed gas dives
  • Lower helium gas costs for deep mixed gas dives
  • Smaller size for technical diving
  • Warm gas will keep you warmer during the dive
  • Moist gas means you will not get a dry throat
  • Very low gas consumption
  • Silent diving will get you closer to marine life
  • Greater simplicity than rebreathers
  • Less maintenance intensive
  • Considerably lower equipment purchase costs
  • Lower training costs
  • Less complex training
  • Smaller size for recreational diving
  • Greater availability and support
  • Less pre-dive preparation required
  • Less discipline and commitment required
  • Lower risk

SSI XR Scuba Schools International Extended Range
TDI Technical Diving International in Rarotonga

At Adventure Cook Islands we offer high quality OC and CCR technical diving courses through TDI and SSI XR. Our courses range from Intro to Tec to Extended Range to more advanced Helitrox CCR courses. Please click on the logos to find out more information about our range of TDI and SSI XR courses.