Saturation diving systems and equipment

Saturation systems and who builds them

Very few companies in the world build a complete saturation diving system, and knowing which is which saves a lot of confusion when reading a vessel specification.

Two corrections to things you will see written elsewhere. Divex no longer exists as a trading brand — it was acquired by James Fisher & Sons in 2013 and now trades as JFD, with its web presence folded into James Fisher Defence. And Hydro Group does not build saturation systems; it is a subsea cable and connector house, which is a different business entirely.

The Comanex position is worth understanding if you work on older tonnage. A very large number of saturation systems in service worldwide descend from COMEX designs, and Comanex holding those files is why it remains the natural source for spares and life-extension work on them.

Helmets and masks

The helmet is the one piece of equipment a diver develops opinions about, and the market is effectively one dominant manufacturer plus specialists.

Gas reclaim

This is a concentrated market and JFD dominates it.

• Electric Gasmizer — closed-loop diver gas recovery. JFD states it has been proven in commercial saturation diving since 1981.
• Gaspure — chamber gas recovery, purifying and recovering chamber atmosphere during operations and decompression instead of venting it.
• Helipure — membrane gas separation, stripping nitrogen, oxygen and argon out of reclaimed chamber gas to purify the helium.
• Ultrajewel 601 — the helmet that pairs with all of the above.

The origin story is worth a line because it explains the 1981 date. The first practical heliox recovery system came from combining Alex Copson's Helinaut valve with Don Rodocker's Gasmizer, and it was proven in service on the HMS Edinburgh gold salvage — the deep saturation job that also set a commercial depth benchmark at the time.

Drass and Comanex also supply reclaim and gas handling plant, so JFD is dominant rather than sole.

Umbilicals and cables

The umbilical carries gas, hot water, communications, power and depth monitoring, and it is the diver's lifeline in the most literal sense. This corner of the industry has consolidated sharply.

Communications

Amron International is the name most people in the trade will recognise, and it is worth a proper profile because it sits at an unusual junction of manufacturer and one-stop distributor.

Amron's own products span the AMCOM communicator series (I through IV), the AMCOMMAND air control systems for one, two and three divers, hyperbaric chamber kit including oxygen treatment hoods, chamber conditioning units and chamber lights, and BIBS masks in the 350M and 450M series — plus umbilicals, bailout whips and spares. It is also a Kirby Morgan dealer, which is why its catalogue reads like the whole industry in one place.

The other significant name is Ocean Technology Systems of Santa Ana, California, founded in 1984 and family owned, which makes hardwire communications, the Buddy Phone through-water transceivers, diver recall systems and the Guardian and Spectrum full-face masks. OTS holds Emmy-winning underwater audio technology, which is an unusual line on a diving company's CV.

On helium speech unscramblers: these are normally integrated into the saturation comms rack rather than sold as standalone boxes, which is why you will struggle to find a model number for one. Amron's AMCOM III and IV and its chamber speaker range are the volume products in this space.

Lighting, cameras and sensors

Tools, cutting and welding

Hydraulic tools are the standard because electricity and seawater are a poor combination and pneumatics behave badly at depth. Stanley Hydraulic Tools of Milwaukie, Oregon is the default brand in the subsea supply chain — JFD resells Stanley critical spares alongside Kirby Morgan and Analox, which tells you where the industry buys.

The standard kit runs to grinders, disc cutters, impact wrenches, drills, chain saws, hydraulic torque tools for flange bolts, and water jetting for cleaning and excavation. Two practical points that surprise people new to underwater work: torque reaction spins the diver rather than the fastener unless you rig yourself to the work first, and mass is not buoyancy — a tool that floats neutral still has all its inertia, so starting and stopping it is exactly as hard as on land.

Cutting is usually oxy-arc, burning a consumable tubular electrode with oxygen fed through its centre. Broco is the recognised name in exothermic cutting rods and torches. Abrasive water jet cutting and diamond wire saws handle larger or more delicate sections.

Welding divides into wet welding — done directly in the water with waterproofed electrodes, quick but metallurgically limited by rapid quenching — and dry hyperbaric welding inside a habitat blown down over the joint, which can meet the same standards as surface welding. Welding procedures have to be qualified at the working depth, because arc behaviour, shielding gas performance and cooling rates all shift with ambient pressure.

Bailout and rebreathers

The saturation-relevant product here is JFD's COBRA — Compact Bailout Rebreather Apparatus — rated to 450 msw with up to 45 minutes of endurance and a one-turn activation, CE marked to NORSOK U101 and EN 14143. The endurance figure matters: a conventional open-circuit bailout cylinder that gives half an hour at the surface gives under two minutes at 150 metres, because consumption scales with absolute pressure. A rebreather changes that arithmetic entirely.

AP Diving of the UK, founded in 1969 as AP Valves, makes the Inspiration and Evolution closed-circuit rebreathers and maintains a military and commercial product line, though it is primarily a technical diving house rather than a surface-supplied commercial supplier.

Launch and recovery

Bell handling systems are almost always supplied by the saturation system integrator rather than bought separately — Drass, SMP and Unique Group all build them, and Thrust Maritime lists A-frames and LARS as product lines. Bell handling LARS also trades actively on the second-hand market.

The design requirement that shapes everything is redundancy: a primary means of recovering the bell, and a secondary means capable of recovering it after the failure of any single component of the primary. That is why a LARS has a main winch, an independent guide-wire winch with an emergency mode rating above its normal one, a clump weight on its own winch, and often active heave compensation on the main hoist.

What it costs

Be sceptical of anyone who quotes you a price for a saturation system, because nobody publishes one. SMP lists every system as "call for price". Brokers publish no asking prices. This is a bespoke, negotiated, low-volume capital goods market.

There is, however, one hard public figure. In November 2016 JFD announced a £35 million contract with Shanghai Salvage for a 24-man, 500 msw system comprising two independent 12-man modules, a diving bell, a hyperbaric lifeboat and the gas management and life support equipment, built to IMCA and Lloyd's Register requirements.

Treat that as an order-of-magnitude anchor rather than a price: it is a 2016 figure, it includes engineering and services, and 500 msw is the deep end of the market. A 12-man 300 msw system would be substantially less per berth.

On rental day rates: there is no meaningful public figure, because saturation spreads are priced inside a vessel day rate rather than quoted separately. A standalone "sat system day rate" is largely a fiction.

Class, certification and the rules

A saturation system is a classed pressure vessel installation, and two parallel regimes govern it: the classification society's rules, and IMCA's guidance.

The IMCA documents

Two things worth knowing. DESIGN is an acronym — Diving Equipment Systems Inspection Guidance Note — not a claim about engineering design. And IMCA's practice is that a new revision does not compulsorily replace the previous edition for up to a year, after which the old version is withdrawn and members must comply with the current one.

The classification societies

Systems are classed by DNV, ABS, Lloyd's Register or Bureau Veritas. The most concrete published rule set is DNV's Rules for classification: Offshore units — Diving systems, supported by the offshore standard for diving systems. DNV distinguishes two notations: Diving system (Surface) for maximum depths under 60 msw with operations under eight hours, and Diving system (SAT) for saturation systems, which requires a dedicated hyperbaric evacuation system. Bureau Veritas publishes its own rule note for the classification of diving systems.

Inspection and recertification intervals

This is the part that determines the real cost of owning or buying a system, and it is where second-hand purchases go wrong.

The second-hand market

Saturation systems do change hands, mostly through contractor inventory disposals and decommissioning programmes. Dockstr is the clearest broker in this space, operating across sixty-plus countries and listing complete 12-man and 18-man spreads, dive bells, living and transfer chambers, gas handling and reclaim equipment and bell handling LARS — including systems originally built by JFD, Drass and Unique Hydra.

No prices are published. Valuation is based on recent comparables and current new-build lead times, and the variables that drive it are depth rating, number of divers, chamber configuration, gas handling capacity and — above all — certification status. An out-of-class system is worth a fraction of an in-class one, and the gap is exactly the cost of getting it back into class.

Who was acquired by whom

This industry consolidates quietly, and a surprising amount of published information about it is out of date. The current position:

Questions

Company details, document revisions and survey intervals verified September 2026 against manufacturers' own sites, the IMCA Guidance Register and technical library, and DNV's rules for diving systems. Ownership in this sector changes frequently — several of the companies above have been acquired within the last seven years.