Saturation Diving

Mixed Gas (Saturation Diving)

Often spoken of as the 'holy grail' of commercial diving. Any diving over the depth of 50 metres is the domain of saturation divers; Highly paid and deep sea divers.
The likelihood of oxygen toxicity and narcosis increases for ordinary air divers at this level of pressure making operations using air an unacceptable limitation for them.
The use of mixed gases that are inert enough to be safe to breathe, while maintaining an oxygen supply is necessary unstead.

Using a blend of Helium and Oxygen saturation divers aka SAT Divers can reach levels of diving exceeding 300 metres. This blend is commonly called Heliox, a mix of oxygen and helium. It's only drawback is the squeaky voice is causes and that it can chill a divers body somewhat.

Training starts typically after a 3 - 4 week course at an IMCA dive school. This course is even more expensive than the Commercial Air Diving Course and is quite challenging.

Sat Diving Operations take place at sea on board Dive Support Vessels.The Saturation System is in three parts. The Rest Area, the Transfer Chamber and the Dry Bell itself. This system can be lifted using a crane to and fro vessels and the mainland as a complete unit. Making it a versatile package.

The divers and all three areas of the SAT system are pressurized down to the depth they will be working from. The divers who are required to go on-shift are then lowered down to the job in a Dry Bell. The gases for breathing off are supplied from large cylinders attached to the Control Room in the DSV that have an umbilical cable attached to the Dry Bell that the divers breath off. Spare breathing gas is attached to the Dry Bell if the umbilical should somehow be cut, damaged or fail to supply gas. The Bell is lifted and re-joined to the Transfer Chamber when it is time for the other shift to take over.

Hot water suits are worn for saturation diving; the hot water being pumped down from boilers on board the DSV to the Dry Bell.

When the time comes for the divers to be decompressed this is done at a very gradual rate of about 15 metres per day. In the 70s and 80s the decompression models were more aggressive than this and nowadays the models are more safe for divers. Nevertheless the story's of bone necrosis associated with SAT diving is still bandied around commercial dive circles. This is considered a less-likely long-term risk with the new decompression models...

It is advisable to commercial divers out there to make sure you have enough experience before taking the plunge. The money SAT divers are on might be pop star wages but commercial Dive Schools are churning out Sat Divers like they are going out of fashion these days and there's only so many jobs...

Training as a commercial diver

From Wannabe Diver to Professional

The initial training itself takes place over several weeks and covers the theoretical and practical aspects of commercial diving. Applicants with prior experience of scuba diving 'may' be able to use this to abate the cost and length of training. Though this is an advantage many Commercial Divers often view recreational divers wanting to 'cross over' with a baleful eye. There is a saying amongst the hard-hat divers that 'you can put a plumber to work under water but you can't take a dive instructor to work as a plumber'. It is this somewhat harsh view that represents the fact that most employers prefer to take on divers who have been tradesmen than former recreational dive professionals.

Training starts typically with a course in recreational scuba diving. Then you progress onto commercial scuba and finally surface supplied. Surface supplied is considered the bread and butter of commercial diving by many. It is considered safe, time proven and versatile. After this unless you are prior trained, courses in NDT, cutting and welding are given. After the training is complete the newly qualified diver is normally given a contact list of companies for work and cut loose to fend for himself.

Training for commercial divers through a dedicated training company is expensive, the price varies but in the UK it can reach in excess of £10,000! The whole concept of these training centers is a moot point among many in the commercial diving community. Many wish for an apprenticeship scheme to be introduced and the training costs to be subsidised by the diving companies. But the fact remains that there is an eager supply of applicants (tempted by often exaggerated earnings by the training organisations) willing to pay for training, which in-turn keeps the companies going.

The actual training tends to differ from country to country so it isn't fair for me to give one example of what the actual instructional methods and techniques are. We are also against the concept of paying such vast sums to commercial training organisations that cannot guarantee work at the end of it hence our slightly biased stance on the training section.

I would strongly suggest that anyone considering a career in commercial diving to think twice. Work is no longer as abundant as it once was and the industry is currently flooded with wannabe divers, many of which end up with only an expensive certificate on the wall to show for their efforts! That said no industry can last if it has no fresh blood to to fill the ranks.

Commercial Diving in the Modern Age

Commerical Diving - Present Day

The trend of using FPSOs (drilling ships) has meant that commercial divers tend to operate from massive Dive Support Vessels (DSVs) which roam the seas carrying out essential work underwater for platform and vessel alike.

The Dawn of the 21st Century has not seen the situation improve but has worsened slightly. Other countries outside of Europe and the USA are now training their own home-grown commercial divers causing the oversaturated market to be flooded further. This is also known to be creating a cheaper labour supply angering the more established and professional commercial divers. There is still a demand for commercial divers but the jobs are often few and far between and the more experienced/qualified diver is almost always chosen over the rookie. The Rise of the ROV is also impacting the employment of commerical divers. The effects are wide ranging but in Norway, a commerical diver cannot legally dive offshore without an ROV watching his every move! Potential helium shortages were an initial worry for commercial dive operators.
However the use of helium re-claimation systems that recycles the helium being used has largely ended that concern.

Commercial Diving

Hard-Hat Diving - The Early Days

Ever since the fledgling salvage operations of men in barrels (16th Century) there have been divers selling their services commercially. By the 19th Century commercial salvage teams were firmly established in Western Europe and the USA. The post WW2 years saw an increase in the fuel resource requirements for industrialised and newly industrialised countries. Questing survey ships sent forth discovered vast supplies of natural gas and crude oil in the seas and oceans. By the late 1960s to 1970s most of these areas had drilling platforms and gas piplines running to the mainland. With the rise of the offshore platform came with it a great demand for dedicated teams of commercial divers to maintain and tend to the underwater machinery and platform supports etc.

Into the Modern Age of Commercial Diving

Through the 1970s and 1980s the commercial divers thrived on the rigs and many consider this to be the 'Golden Age' of Commercial Diving with even rookie divers earning small fortunes. Bank balances were high, oil and gas output was in abundance and you could almost hear the Boom Town Rats playin' it for the boys and summing up the success.


Then the 1990s arrived and things began to slow down. The Oil and Gas extraction amounts no longer reached the capacities of the 1970s and 80s (although in 1999 it did break the record). Amid fossil fuel depletion and environmentalist concerns, offshore platforms no longer saw the output they had once reached. This along with the use of ROVs in lieu of divers has meant commercial diving is no longer the job it once was.