Atmospheric diving systems (ADS) reached their heyday when they provided a cost-effective, light-weight and reliable alternative to saturation diving for offshore drilling support. Remotely operated vehicles (ROVs) were on their way, but had not reached maturity in useful task execution and particularly in reliability. Since those heady days of the late 1970's and early 1980's, ADS has found its role increasingly squeezed by the existing competition from manned diving for "real work" and especially by the capability, reliability and above all safety of ROVs. Even though ADS had more dexterity and on-site in-water presence and thinking capability than an ROV, the attraction of taking man completely out of the high risk underwater environment always gives the initial edge to the ROV. So where does this leave ADS? There still are a number of key jobs for which ADS is the ideally suited intervention method. This paper covers the background of the development of ADS in the offshore oil and gas arena. It reviews some of the most useful ADS jobs carried out recently and considers the factors determining the selection of the best tool for the job from the underwater intervention tool box so that the real benefits of ADS in operation can be maximised.
Although the first atmospheric diving suit (ADS) appeared in the early part of the twentieth century, these systems were only developed in any numbers for commercial use during the 1970's. This slow start was due to several causes. The designers were limited by technology in the early development and construction of practical ADS. Experience of operations was only gradually gathered so that the necessary improvements to make ADS practical, safe and useful only came slowly. An underlying cause was largely due to lack of pad work opportunities to justify the necessary investment in commercial terms. The growth of the offshore oil and gas industry stimulated the possibilities for ADS work and lead to the larger numbers available by the late 1970's.
Prior to this, the majority of Interest in developing and using ADS was for military (naval) applications Public money often can be made available In large amounts. The manufacturers wlll also invest more since the military returns can be greater. Production numbers for a successful military ADS development are some ten times greater than would be justified for just the offshore commercial field. However, it is the use of ADS in the support of offshore oil and gas exploration and production that concerns us here. Companies such as Oceaneering and Can-Dive were quick to realise the commercial potential for ADS and to both support their development and to become directly involved. Looking back over the last fifteen to twenty years, it is possible to trace the factors that have lead to the design and safety features that have become standard for today's suits. The peak of offshore commercial activity for ADS was around the 1979 – 1981 period. Subsequently their commercial use offshore has declined