Technical Diving


Welcome to Go Dive’s Rec Tec page

The term technical diving was coined in the early 90’s and is misinterpreted by many as a type of diving set-a-side for adrenalin junkies and those with unlimited disposal income.

Tec divers are not thrill seekers or fools who simply disregard limits; on the contrary, they recognize that limits exist for legitimate risk management reasons. They seek to render the limits obsolete by applying new equipment and methodologies. In this sense, tec divers are diving’s future. They are diving’s innovators, explorers and problems solvers. They see change, challenge and choices, not, one size fits all, diving.

Since the early 90’s technical diving training, techniques and equipment have evolved faster than any other area of the dive industry, to the point where the line between recreational and technical diving is no longer definable. Go Dive prefers to use the term Rec Tec as a more appropriate term in today’s evolving market

Go Dive is lucky to have the Mikhail Lermontov one of the best wreck dives in the world on our back door step – a wreck which can be made as challenging as your training, kit and experience allow.

Go Dive's Rec Tec Group

Go Dive Rec Tec Group

We are now hosting on a very regular bases rebreather and open circuit technical divers and have become the preferred training location for many Instructors whom teach Rebreather and Advanced Wreck training. In fact we are now probably one of New Zealand?s most active Rec Tec facilities.

Go Dive run regular TDI & PADI Nitrox, TDI Intro to tech, Advanced Nitrox, Decompression Procedures, Side-mount, Gas Blender, Advanced Wreck and Extended Range courses, all based from our fully equipped dive lodge in Port Gore. Go Dive is also the founder and organizer of TecFestnz, New Zealand’s one and only technical diving festival held each May at Lake Taupo.

Here is why you might consider Rec Tec and how it will increase your comfort and skill level, whether your on a shallow recreational dive or a deep, long, decompression dive inside a wreck.

Recreational courses offered by the major training agencies focus on the basic skills of diving, enough to where you can comfortably dive independently of a dive professional in a particular environment. Few of these courses allow enough time for you to truly master your buoyancy to a level where you can with ease hover horizontally in the water column while performing tasks such as deploying an SMB, sharing air or removing and replacing your mask. Nor do these courses take you to a point where you can communicate with your buddy beyond the most basic level or calculate and plan your air consumption rate, a great skill if you want to know how long your gas is going to last underwater – a pretty important part of dive planning.

Grant Pearce dives the Lermontov on GEM Side Kick.

Grant Pearce dives the Lermontov on GEM Side Kick.

Buoyancy control, gas management and correct fining when wreck, cave, or decompression diving is critical, without these skills things can turn nasty pretty quickly. Right from the Intro to Tech  course we will be discussing and developing your weight system distribution and buoyancy techniques, plus discussing and practicing some useful hand signals which can be used to determine time, pressures and depths with your dive team.

Along with these useful new skills, you will also learn to focus more on what we see as the five key differences between recreational and technical diving:

  1. Situational Awareness.

  2. Self-Reliance

  3. Hazard Management

  4. Team Work

  5. Planning and Contingencies.

Rec Tec Equipment

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DIN Valves

There are two types of valve fittings for SCUBA cylinders. Open face, Yoke or A-Clamp, which until recently have been a standard in New Zealand and 200 Bar or 300 Bar DIN.

Tec divers prefer the DIN fitting as the O-ring is in-captured in the valve and far less likely to fail than the A-clamp O-ring that can extrude itself from its seat if the regulator is given a good thump while moving through an overhead environment like a wreck or cave. DIN valves also offer a far greater gas flow.

Sling Cylinder and Regulator

Diving at depth and in an overhead environment like a wreck requires redundancies, with air supply being the one that needs to be given the most consideration.

Many divers begin their journey into this environment by side-mounting a single 6 litre alloy cylinder and regulator to their standard recreational kit. This not only gives you air redundancy in case of loss of back gas, but the ability to accelerate your decompression by carrying a decompression gas which is at a higher O2 percentage than your back gas.

The investment in such kit is under NZ$1000.00, but the rewards in way of expanding your diving experiences are huge.

Double Back-mounted Cylinders

Like the sling cylinder, the reason for carrying doubles is again about redundancy. The difference is that they are large volume cylinders carried on your back and linked together by an isolating manifold. This gives you a far greater volume of gas, and redundancy in the case of a hose, valve, regulator or O-ring failure. This allows you to plan and execute dives for a longer period of time than a just a single and a sling would allow.

With the right planning when purchasing kit for the first time or replacing existing kit, all you need to do is add a second cylinder, manifold, bands, second regulator and wing and you’re good to go.


Side-mount Systems

Side-mount Cave diver negotiates a tight squeeze

Side-mount cave diver negotiates a tight squeeze

Like back-mounted doubles, side-mounts offer the user larger volumes of gas, which in turn allow longer run times and increased safety. The difference being that they are mounted on each side of the diver with each cylinder and regulator run independently of the other. Side-mount systems have been used by cave divers since the 1960’s due to the lower profile they offer when negotiating tight cave restrictions and convenience when transporting, they do however offer many advantages over back-mounted double systems for the open-water divers, due to ease of handling when donning and removing kit, reduced setup costs and adaptability back to a single back-mount configuration for those shallower dives.

Semi Closed and Closed Circuit Rebreathers

On inhalation we breathe in 21% oxygen and on exhalation we exhale 16% which works out about 25% of the O2 inhaled. Our tissues metabolize this O2 to live and work, and in turn produce carbon dioxide (about 3-4%)

A rebreather can be presented as a fairly simple concept. Take this carbon dioxide out of the exhaled air and add some O2. A rebreather is essentially a breathing loop; this consists of our lungs, the mouth piece, the counter lungs, a scrubber and the hoses that connect the components. The exhaled air goes into the exhalation counter lung, O2 is added before it goes to the scrubber, this gas then heads to the scrubber, where CO2 is removed through a chemical reaction, then heads into the inhalation counter lung, and then back to the divers lungs.

There are four main types of rebreather’s available to divers. The O2 closed circuit, the semi-closed circuit (SCR), closed circuit electronic (CCR) and manual closed circuit (CCR)

The main advantage of SCR and CCR’s is that they conserve gas, and in the case of trimix diving this allows for a huge saving in helium. For example an open circuit dive using trimix 18/40 to a depth of 70m for 90 minutes total run time would cost you in New Zealand around $250.00, on a SCR using a 5/1 mouthpiece it would be around $75.00 and on a CCR around $50.00.

In the case of the CCR they mix your gas on the fly, so you get the optimum blend of gas for the depth, this can reduce your decompression obligation.

SCR rebreather’s in many cases marry up with your existing scuba kit and tap into the gas you have blended, they are simpler to use and far cheaper to buy. If your intention is to do shallow moderate depth dives, then these are a great option

No Dives arranged yet. We are working on it.


TDI & PADI Nitrox

Nitrox is about bottom time not depth. It allows you to extend your bottom time and maximize your investment in all your kit and training. With planning consideration it can also add a conservative element to your diving in some situations.

Your understanding of decompression theory and the importance of proper dive planning will be expanded; you will complete at least two Enriched Air dives with Go Dive on the wreck of the Lermontov.

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  • Open water diver

Kit requirements

  • Standard recreational diving kit (rental available)

Go Dive supplies

  • Nitrox compatible cylinders

  • O2 Analyzer

  • Gas Blending services


TDI Intro to Tech

What’s Technical diving all about, how do I get started, what about CCR’s, Side-mounts or back-mounted doubles, what’s run time, SAC/RMV rate, long hoses, short hoses, which kit configuration is for me? All these questions and many more will be answered during your “Intro to Tech” course with Go Dive.

This course introduces you to the world of technical diving. The objective of the training is to familiarize you with equipment configurations, to enhance your open water diving skills, such as buoyancy, trim and situational awareness and to introduce you to advanced gas planning techniques. The course is a strictly a no decompression course, you will be diving enriched air mixes, provided the gas mix is within your current level of certification.

Whether you choose to continue on to Advanced Nitrox and Decompression Procedures or simply use this training to improve your diving skills, the “Intro to Tech” course should be on every diver’s list.

Online Theory Option


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  • Minimum age 18, 15 with parental consent

  • Minimum certification, Open Water or equivalent

  • Provide proof of 25 logged dives

The course is held at our Dive Lodge in Port Gore over two days and includes 3 training dives to a maximum depth of 23m or 18m if you hold an Open water certificate. At least 2 of the dives will be on the wreck of the Mikhail Lermontov, with a fourth non training dive on the wreck if no remedial training is required and time allows. Two night’s accommodation with meal’s, transport ex Picton, air and technical diving equipment, including the choice of side-mount or back-mount doubles are included in the ITT package. You supply your own recreational kit.


TDI Sidemount Diver

Sidemount diving has an interesting history, dating back as far as the 1960’s where cave divers in the UK developed sidemount diving techniques. Over the years the equipment has evolved with the help of companies like Dive Rite in the States and it has now become the configuration of choice for many technical and recreational divers who are exploring further into wrecks, caves or wanting to extend their bottom time or dive solo.

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TDI’s sidemount Diver specialty is the perfect course for any recreational or technical diver wishing to use this increasingly popular equipment configuration. It teaches you how to safely utilize side-mounted primary cylinders as an alternative to the traditional back-mounted method. The course will take you through the specific techniques, planning procedures and skills that set sidemount cylinder diving apart from the traditional back-mounted method.  During the course, your Go Dive Instructor will take you on a minimum of three dives over two days and cover skills such as:

  • Equipment considerations

  • Gas management 

  • Attaching cylinders

  • Trim and buoyancy

  • Deployment of surface marker

  • Different water entries


  • Minimum age 18

  • Minimum Certification; SDI Open-water or the equivalent

Kit Requirements

  • Standard dive kit

  • Backup computer or alternate depth/timing device

  • Sidemount BCD/Harness (can be rented from Go Dive)

  • 2nd Regulator (can be rented from Go Dive)

Go Dive Supplies

  • Dual, O2 compatible cylinders

  • O2 Analyzer

  • Gas Blending services

  • Accommodation at our Dive Lodge with meals


TDI Advanced Nitrox

Advanced Nitrox talks about mixes above the standard 22 to 40%. It will give you the ability to use high levels of O2 breathing mixes to greatly increase no-decompression bottom limits at moderate depths and to use high level breathing mixes to speed up decompression times, as well as to enhance you’re off gassing during a safety stop.

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  • Minimum age 18, 15 with parental consent

  • Nitrox certification

  • 25 logged dives

Kit requirements

  • Standard dive kit

  • SMB and finger spool

  • U/W Slate

Go Dive Supplies

  • Nitrox compatible cylinder

  • Sling/Stage cylinder and regulator

  • O2 Analyser

  • Gas Blending services

  • Accommodation at our Dive Lodge with meals


TDI Decompression Procedures

Every dive you do is a decompression dive, it is just that some require a mandatory stop and some just a safety stop. This course helps you understand the principles behind the dives you plan that require a decompression stop. How to use the equipment that may be used to execute these dives and will introduce you to diving using twin cylinders. The course is in most cases run in conjunction with the Advanced Nitrox. Although a Nitrox certification is not a prerequisite, it is highly recommend as it allows you to accelerate your decompression using high percentage mixes of Nitrox or 100% O2.

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  • Minimum age 18 years

  • Advanced Open Water Diver (Adv Nitrox highly recommended)

  • 25 logged dives

Kit Requirements

  • Standard dive kit

  • SMB & Spool

  • Underwater Slate or wet notes

  • Backup Mask

  • Wing & Harness (can be rented from Go Dive)

  • 2nd Regulator (can be rented from Go Dive)

Go Dive Supplies

  • Single and Twin, O2 compatible cylinders

  • Deco cylinders

  • O2 Analyzer

  • Gas Blending services

  • Accommodation at our Dive Lodge with meals


Entering the pool enclosure on the Mikhail Lermontov
Entering the pool enclosure on the Mikhail Lermontov

TDI Advanced Wreck

Warning wreck diving can be contagious, especially when diving a wreck like the Mikhail Lermontov. It can also be hazardous to the unprepared and correct wreck diving techniques and equipment are essential to stay safe. Recreational wreck courses only allow you to stay within the recreational zone of a wreck, however often the best visibility and points of interest are deep within the wreck, take for example the engine room of the Lermontov.

The Advanced wreck course will cover such skills as proper line deployment, lost line, lost buddy and loss-of-sight techniques. We will cover reverse fining, helicopter turns, plus much, much more. As an instructor, I would say this is one of the most fun and rewarding courses to teach, not to mention humouros. But prepared to be challenged, past students have commented this is the most challenging course they have completed.

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  • Minimum age 18

  • Advanced Open Water or equivalent

  • Provide proof of 50 logged dives

  • Be certified as a basic Wreck or Cavern Diver

 Kit requirements

  • Back-mounted twins or side-mounts with regulators ( can be rented from Go Dive)

  • Wreck reel and finger/safety spool

  • Back up mask

  • Primary & Back-up lights

  • Backup timing and depth devices

  • Underwater slate or wet notes

  • Two line cutting devices

 Go Dive will supply

  • Sling cylinder

  • Twin cylinders if required

  • Practice wreck reel

  • Gas blending services if Nitrox qualified

The course is held at Go Dives Lodge in Port Gore, you will do 6 penetration dives on the Mikhail Lermontov over three days, with an accumulated minimum bottom time of 100 minutes, but normally averaging around 350 minutes. Two of these dives may be credited towards the total dives required for Adv Nitrox, Deco Procedures or Extended Range.

The Advanced Wreck package includes 4 nights accommodation with meals at the Lermontov Lodge, training materials, transport ex Picton, cylinders, air and 4 days diving.


 TDI Extended Range

The Extended Range course provides training and the experience required for you to competently utilize air up to 55 metres that requires staged decompression, utilizing nitrox of oxygen mixes during decompression. The objective of the course is to train you in the proper techniques, equipment requirements, and hazards of deep air diving. It follows on and builds on the skills you acquired during your Decompression Procedures course and prepares you for trimix training and deeper trimix dives.

You will finely hone your existing skills and be put through some real world scenarios that test your comfort level and contingency planning.

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  • Minimum age 18

  • Certified as an Advanced Nitrox Diver and Decompression Diver or equivalent

  • Provide proof of 100 logged dives, of which 25 must be deeper than 30 metres.

The Extended Range course is run over a 3 day period, while based from our Dive Lodge in Port Gore. You will complete four dives all over 30 metres with two over 40 metres, with a minimum accumulated bottom time of 100 minutes. Two of the dives being on the Mikhail Lermontov.

At Go Dives discretion, 2 dives may be credited from your Advanced Wreck course towards the total amount of dives required.

Included in the ER course package is 3 nights’ accommodation with meals at the Lermontov Lodge, transport ex Picton, gas, twin and stage cylinders, training materials and diving.

You need to supply all your own kit, including regulators, computers and redundant depth and timing devices.

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These courses are listed in an order of progression that is recommended by Go Dive and our experienced instructors. Sidemount is a configuration based course designed to help divers adjust to the differences between that and ‘standard’ or backmounted twins. Due to its usability it can be applied to any level of diving from recreational through to Advanced Trimix. Although it isn’t necessary to follow this exact pathway, the learning of new skills and knowledge development fits well – with skills and knowledge following naturally onto the next level. For example to complete the advanced wreck training without Adv Nitrox training would severely limit your time on some wrecks, including the Lermontov. Example being a dive on air into the engine room at 33m with a BT of 40 minutes would result in a 9m stop for 2 minutes, 6m stop for 8 minutes and a 3m stop for 23 minutes or 73 minutes total RT. Where the same dive on Nitrox 32% using 100% deco gas at the 6m and 3m stops would result in a 12m stop for 1 minute a 9 m stop for 2 minutes, 6m for 2 and 3 for 5 minutes, so a total of 52 minutes RT with ascent times taken into consideration, so 21 minutes less in the water and 21minutes less gas required.

* Calculations based on Bulhmann air tables and Deco Planner software

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