Technical diving with mandatory decompression
PADI Tec 45: technical diving
Course description
PADI Tec 45 is the direct continuation of Tec 40 and the second module of the PADI Tec Deep Diver programme. This is the point where decompression stops being an exercise within safe limits and becomes a real obligation: you may not surface without the stops.
Compared with Tec 40, two key things change. First, the decompression time limit disappears. At this level, the only limit on your decompression obligation is the amount of gas you can carry, which completely changes the logic of planning. Second, accelerated decompression appears, with gas containing up to 100% oxygen, and with it serious consequences for a mistake when switching gas.
The programme covers precise dive planning with decompression software, managing bottom gas and decompression gas, stability on the stops, and reacting to emergencies in an environment where direct access to the surface is not possible. Participants work on real profiles, in a full technical rig, backmount or sidemount, always with a decompression cylinder.
Every stage ends with a detailed debrief: an analysis of how the dive went, the decisions taken and how the team worked together. The goal of the course is to build the competence and confidence on which further technical development can rest, not simply to extend the depth limit by five metres.
4-5 training days, depending on local conditions and the pace of the group.
3 theory sections, 3 practical sessions (skill exercises), 4 training dives of increasing complexity.
4 training dives. The first skills session can be done in confined water.
Maximum depth: 45 metres.
No decompression time limit: the only limit is your gas supply. Accelerated decompression.
A maximum of 3 people per instructor. In practice we most often run teams of 2.
Bottom gas: air or nitrox. Decompression gas: one, with an oxygen content of up to 100%.
The course can be completed as PADI Tec 45 Trimix, using trimix with up to 40% helium as the bottom gas.
For divers who have completed Tec 40 and want to dive with decompression with no time limit and prepare for Tec 50.
The PADI Tec 45 certificate qualifies you to plan and carry out dives on your own:
- to a depth of 45 metres,
- single and repetitive, with mandatory decompression,
- with one decompression cylinder with gas of up to 100% oxygen, used to speed up decompression or add conservatism,
- in a team of divers with suitable qualifications.
Tec 45 is a prerequisite for the PADI Tec 50 course and counts towards the full PADI Tec Deep Diver programme.
- Age: 18 years old;
- Technical certification: PADI Tec 40 Diver or an equivalent certification from another organisation;
- Rescue certification: PADI Rescue Diver or equivalent. With a qualification from another federation, proof of first aid and CPR training from the last 2 years is required;
- Experience: at least 50 dives recorded in a logbook, including at least 10 to a depth of 30 metres or more;
- Health: a current medical statement (signed by a doctor within the last 12 months).
Unlike Tec 40, where Rescue Diver is only recommended, at Tec 45 level it is a formal requirement. We assess qualifications from other federations individually.
Main configuration
- a twinset with an isolation manifold, or a sidemount set: two independent cylinders,
- a backplate and a one-piece harness,
- a wing with lift suited to the configuration,
- two independent regulators: a primary on a long hose (about 2 m) and a backup on a bungee under the neck,
- a pressure gauge on each first stage,
- a weighting system matched to the configuration and exposure.
Decompression cylinder
- one decompression cylinder (typically 7-11 l) prepared for work with oxygen: oxygen cleaning, suitable lubricants and seals,
- a separate regulator with a pressure gauge, a hose of about 90-110 cm,
- a cylinder harness with double-ended bolt snaps,
- clear marking of the mix and the maximum operating depth (MOD).
Instruments and safety equipment
- a multi-gas dive computer and a second independent instrument for time and depth,
- backup buoyancy control: a second lift bag, or a dry suit with light cylinders (a buoy does not count as backup buoyancy control),
- a decompression buoy and a reel or spool of at least 30 m, plus a spare buoy,
- two cutting tools placed independently,
- a backup mask,
- an underwater slate with the dive plan,
- a main light and a backup light for limited visibility.
Also recommended
- a dry suit with an undersuit suited to the exposure time,
- the decompression software used for planning,
- your own oxygen analyser,
- a basic set of tools and consumables.
Training fee
The price is set individually, depending on where the course takes place and on logistics.
Registration and certification fee
According to the current price list of the certifying organisation.
Training materials
The PADI Tec Deep Diver package, charged separately unless it was bought with the Tec 40 course.
Additional costs
Breathing gases (including oxygen), technical equipment rental, dive logistics, travel, accommodation and meals.
Theory
The theory part covers three sections and prepares you to plan dives with mandatory decompression on your own:
- advanced decompression planning: decompression models, gradient factors, interpreting and critically assessing generated profiles;
- gas planning with no decompression time limit: reserves, an emergency scenario for the whole team, the consequences of losing decompression gas;
- oxygen exposure when working with gas of up to 100% oxygen: central nervous system and pulmonary toxicity, dose control, MOD;
- the physiology of technical diving: tissue on-gassing and off-gassing, risk factors for decompression sickness;
- how technical equipment works and how to maintain it, and preparing equipment for work with oxygen;
- emergency procedures and team responsibility when there is no direct access to the surface.
Practice
The practical part brings the theory into real technical diving conditions:
- configuration workshops: preparing a technical rig with a decompression cylinder;
- the gas switch procedure, done in a fixed, repeatable sequence and confirmed within the team;
- staging, handing over and retrieving a decompression cylinder underwater;
- holding decompression stops with a set accuracy, including while a buoy is deployed;
- sharing gas on the move and valve procedures under full task loading;
- emergency scenarios: loss of decompression gas, uncontrolled gas release (free flow), interrupted decompression;
- single and repetitive dives with a real decompression obligation.
The pass criterion is not doing the exercise but repeating it: the skill must be performed correctly, calmly and while keeping control of position and situational awareness.
FAQ
Projects
Dives with a specific task to complete: the most effective way to make the procedures from the course a habit:
- consolidation dives: the first decompression dives after the course, supervised by our staff but no longer in a training format;
- wreck projects: documentation, identification and measurement of sites within your qualifications;
- underwater photography and photogrammetry: working with a camera under a real decompression obligation;
- exploration and mapping: line work, sketches, planning gas reserves;
- research and conservation cooperation with institutions that care for underwater heritage.
We choose team members by training level, not by the order of applications. If a given project is too early for a diver, we suggest an intermediate path.
Trips
Several days in a row with the same team build experience faster than the same number of dives spread across the whole season:
- trips within Poland: lakes and flooded quarries, weekend format, demanding thermal conditions and limited visibility;
- the Baltic: wrecks within 45 metres, dives from a boat;
- trips abroad: warm water and good visibility, longer decompression exposures;
- small teams, a dive plan of increasing complexity and gas supply arranged before the trip;
- an emergency plan that includes the nearest hyperbaric chamber, and staff supervision on site.
Before a trip it is worth planning an equipment check, a check dive in the target configuration and insurance that covers decompression diving. We keep the trip calendar separately.
Further training
A natural continuation after Tec 45. The order depends on which direction you want to develop your diving range:
- PADI Tec 50: dives to 50 metres with two decompression gases;
- PADI Tec 45 Trimix: normoxic trimix within your current qualifications, if reducing narcosis is the priority;
- PADI Tec Sidemount: if the course was done in backmount and you want to master both;
- PADI Tec Gas Blender: preparing gas mixes yourself, including decompression gases.
Tec 45 training counts towards the full PADI Tec Deep Diver programme, so moving on to Tec 50 does not mean repeating material.
