This is an age in which the technological development of Oil and Gas Industry is a main drive.
We are very distant from the beginning of the XX century, when we first start progressing from the onshore exploration to the offshore discoveries.
The history of the Offshore Support Vessel (OSV) follows the same course of the amazing technological development allowing the exploration of the Ultra Deep waters.
The first incursion into the offshore beyond the sight of land happened in 1947, with the first productive well located 10.5 miles far from the Louisiana coast and drilled in water depths of 18 feet. With the success of the Creole field, later with 10 additional wells, the investors were assured of the feasibility of offshore exploration. And this, in conjunction with a growing demand of oil, “fueled” aseries of technological developments in a multitude of areas…
From the drilling units themselves, passing by geological survey techniques, to weather and sea conditions research and treatment, all areas connected with the offshore industry have known aprogress that defies the most dairy dreams. It couldn’t be different with the OSVs…
The first Offshore Support Vessels
After the II World War, the available units used to transport people, equipment and supplies to the offshore wells were fishing vessels or retired military vessels. This was not their design function but, with some adaptations, it served their basic transport purpose.
In 1955, the first purpose built vessel for the offshore industry saw the light of day. The “Ebb Tide”,with its bow wheelhouse and a long flat afterdeck, pioneered a design which resisted the test of time, and become a standard for offshore support vessels.
This vessel’s characteristics allowed her to be moored offshore for the discharge of cargo, maneuver and manhandle the cargo using equipment originally designed for fishing trawls. She was only 127 ft long and had a registered tonnage of 150 tons, which seems very small in nowadays but, in fact, it was considerably larger than the previously used workboats.
Some of these very first OSVs were equipped with A-Frames and a small roller at the stern, for handling anchors and allowing the wire to be paid out. It was a model with multiple applications, depending on the required support, very well adapted to the conditions of the Gulf of Mexico (GoM).
GoM versus North Sea
The discovery in 1959 of the Groningen land gas field, in the Netherlands, followed by the discovery of gas in the east coast of the UK, confirmed that the Southern North Sea was potentially interesting for the Offshore Industry. Oil exploration in this geographical area started during the 60’s but only in 1969, the first ‘oil strike’ produced enough oil to convince the major oil companies investing in it.
At that time, the only available experience and technology of the Offshore Industry was acquired and designed to be operated in the GoM. With the weather conditions of the North Sea, producing large
waves driven by winds often exceeding 180 Km/h at its worse, the perfect GoM OSV design was no longer enough.
Most of these ships that followed the accommodation forward, clear deck aft design with twofunnels right aft, minimum freeboard aft (in some cases, inches above the waterline…), steel decksand rudimentary equipment as bolted “stand alone” winches for towing and anchor handling, couldnot cope with the harsh conditions of the North Sea.
Many suffered major power losses caused by wash down of the funnels that completely stopped the main engines, their steels decks allowed the cargo to slide and, consequently, affecting the stability, and their crews were almost always working in a wet and slippery deck. To respond to the special needs of European waters, UK ship owners took the basic design and develop it further to better suit the environmental conditions and were shortly followed by the Norwegians.
The first vessels produced followed the accommodation forward, low working deck aft types but with amidships funnels and the electric or hydraulic powered winch, many times undercover in a separate winch room, like in the deep sea tugs. But it is only with the entering in service of the Ulstein designUT 704 that the standard “European” Offshore Support Vessel is closer defined.
This vessel was equipped with two Nohab main engines producing around 7040 BHP and with a 500 HP bow thruster which provided a remarkable and innovating maneuverability; the winch control was now done from the bridge, with improved view of the working deck, leading to safer operations. The abilities of this design included an increased bollard pull of some 80+ tons, a semi-enclosed hydraulic towing winch and a workable deck of 124 feet long by 36 feet width built to take a cargo load of 850 tons with a strength rate of 5 tons/m2 on wooden sheathed decks. It was, also, the first vessel of its type built with rounded quarters, allowing the free movement of the tow wire during turns, and provided with hydraulic pins which rose from the deck and trapped the tow wire.
The characteristics served the multi-task requirements of offshore support. Both rig owners and charterers liked the design and, between 1975 and 1987, a total of ninety one vessels were built. It is called the original workhorse of the industry and can be said to be a mark in the technological development of the Offshore Marine Industry.
Shallow waters versus Deep/Ultra Deep waters
From 1945 to 1975, the demand of oil increased rapidly, tripling in the United States, becoming fifteen times bigger in Europe and being enormously multiplied by one hundred and forty seven times in Japan. This fact combined with the rise of OPEC and the high oil prices, boosted the investment in the North Sea and led to the greater exploration for larger fields in deeper waters in the GoM.
The emergence of new technologies during the 80’s has contributed for breaking the 1,000 feet barrier of the “Deep Water” accepted definition. With the better understanding of the geological movements, namely of the deposition of turbidite sands and of the complex relationships to subsea salt, the Deep Sea reservoirs revealed to be above the expectations. And again the Offshore Industryshows to have an incredible ability to solve problems…
Parallel to the growing of the industry, the lessons given by tragic accidents like the Santa Barbara spill of approximately 80.000 barrels of oil in 1969 or the explosion and fire of the Piper Alpha in 1988, with the loss of 167 workers, has led to the adoption and implementation of tighter safety measures . The safety requirements for the installations increased and the OSVs added to their features, emergency response equipments such as the FRC (Fast Rescue Craft), anti-pollution and containment barriers and fire fighting assistance. Today it is recognized that the offshore industry is very safety conscious, for from it depends its very survival.
With the advances into the deeper offshore and the increased exploration, other requirements of support emerge. The vessels need higher engine horsepower (to handle heavy Rig anchoring gear), greater cargo capacity (more quantity is needed per voyage), and to be faster (longer distances from shore) in order to meet all kinds of demands of the new generation deepwater rigs.
A trend of change is evident in the basic design of the OSV’s:
They will have to be larger and more powerful and, meanwhile, the use of Dynamic Positioning (DP) has almost become the norm.
The new generation of OSVs are indeed larger in size, in order to provide bigger cargo deck areas and to optimize the under deck spaces with increased number of bulk tanks for liquid mud, brine and cement. The higher specification for towing and anchor handling, has conducted to the introduction of sophisticated anchor handling equipment and thrusters for dynamic positioning capabilities. Requirement for higher Bollard Pull has raised the trend to a range of 150 to 200 T.
As illustrative example of the evolution status of OSVs, the current high-horsepower AHTS have a total main engine exceeding 25,000 BHP, Bollard Pull above 300 T and stern roller diameter greater than 4m. The anchors that they have to handle require winches of, at least, 600 T brake capacity and chain lockers enough to store around 1000 m3. The introduction of robotic cranes for handling of the outsize gear is being tested, mainly consisting of one crane on each crash rail, with their booms and robotic arms adjustable to reach and work in any part of the main deck.
Despite the fact that accommodation and navigation bridge position remain almost unchanged, agreater emphasis in the crew’s comfort and good ergonomics is integrated in the new generation of OSVs. Recently, new designs have made the deckhouse bulkhead rake aft, consequently reducingwind resistance and green sea loads. Navigation Bridge’s new design concept is similar to the onefrom airport control towers, aiming to achieve all-round visibility and hull forms tend to pass from straight chimes to streamline curves.
With the move into deeper waters, the subsea systems have become an essential part of offshore E&P mainly due to their improved technology and achieved cost savings. Today, the Capex requirements difference between a topside production platform and 4 subsea wells installation might be on the order of 100%, and the time required to install it is often inferior to one year. In accordance with the subsea installation, intervention and maintenance requirements, some of the new generation of OSVs is equipped with ROV for underwater operations and lifting appliances with high working loads and heave compensators for cargo/equipment handling.
In addition, the Diesel Electrical Propulsion evolution has contributed with significant changes in the possible layout of the OSVs. The long propeller intermediate shaft can be eliminated and the main
engines are replaced by alternator engines, being placed at a higher deck, therefore improving bulk capacities. The motor is cost effective and suitable for straight shaft or Azimuth propeller drives. It also features higher fuel efficiency and produces lower emissions which meet the needs of sustainable development.
In resume, the evolution of the offshore exploration was guided into progressively deeper waters and conducted the development of the Offshore Marine Industry to bigger (longer and deeper) vessels, more powerful, with more cargo space, greater space efficiency, technologically very sophisticated and with increased versatility.
In the beginning of the Offshore Industry, the classification of support vessels complied basically hull structural, essential propulsion and auxiliary machinery requirements. Any special function, such as towing, was not covered by the Class regulations. Only in 1981, when IMO adopted the ResolutionA.469(XII) “Guidelines for the design and construction of Offshore Supply Vessels”, it was recognized that the particular features and service characteristics of OSVs could not be fully covered by the criteria applied to conventional cargo ships and specific safety requirements were introduced.
These guidelines refer to SOLAS 1974 standard of safety but introduce certain provisions to suit the nature of OSVs, namely in respect of stability criteria. Alternative stability criteria are prescribed and a minimum freeboard at the stern of, at least, 0.005L is recommended. In addition, as safeguard against collision damage, the Res. A. 469(XII) introduces damage stability requirements with assumed longitudinal, vertical and transverse damage extents. But, despite this new approach, the IMO resolution did not address other statutory aspects, obligating ship designers to find compromise solutions and Flag Administrations to issue exemptions in a case-by-case basis.
As the application of this resolution was not mandatory, its impact in the new builds was not promptly felt. Over the years, IMO and other recognized institutions like IMCA have issued and adopted several documents, mostly of voluntary compliance. Operators in the Offshore Industry have gladly welcomed the guidance and their application has become part of the Industry recommended practices.
The Classification Societies began to incorporate the notions contained in the referred guidance in their own rules. Vessels specialized functions, like towing, fire fighting, oil recovery and safety standby are introduced and proposed as optional class notations. Similar measures are taken forspecific vessel’s performance capabilities as the DP, habitability and bridge ergonomics.
Today, most of the respected Classification Societies are adopting the OSV notation, as well as the specialized function notations (e.g. FiFi 1). The Offshore Support Vessel is starting to have a dedicated regulatory regime necessary to face the next demanding challenges of safe operations in increasingly harsher environments.
The recovering of oil prices and the high number of undeveloped deep water discoveries seems to assure a secure future for the OSVs on the demand side.
Around 2005, the offshore industry had an aged OSV fleet with 45% older than 25 years and 29% aged between 20 and 25 years old. In 2010, the numbers changed and the average age of the fleet was already lower than 18 years. Fleet’s age structure analysis revealed the existence of two distinctfleets, being the old fleet composed by the bigger number of vessels and the new one comprising the largest portion of tonnage.
This confirms the trend to build bigger, heavier and more powerful vessels. In addition, the order book size and composition, with an obvious shift from supply vessel to anchor handler construction, indicate that owners and operators are willing to invest in more capital-intensive vessels for the perspective of obtaining additional charter rates in the market.
The use of this new generation of OSVs, provided with sophisticated technology, faces another major challenge:
Where to find competent crews to operate them?
The increased demand of seafarers allied to the constant introduction of new technologies and crew certification requirements, was not foreseen or prepared. The upcoming change, in January 2012, of the qualifications required to become DP Operator illustrates clearly the situation. Previously, anybody with minimum academicals formation could become a DPO; from January 2012, only persons certified as bridge officer are allowed to apply for the course. Until now, the operators have already been struggling to have properly certified DPOs on board; from next year on, if no further measures are taken, it will be much worse as the number of possible candidates has greatly been reduced.
The case of DPO certificate is only an example, among many available, of the manning and competence problems already strongly affecting the owners and, in consequence, the operators. The operational dangers of the offshore industry increase with the move into deeper waters, requiring greater competence and safety awareness. The vessels get bigger, technologically more sophisticated, performing very demanding tasks. With the shortage of qualified personnel, both Contractors and Companies will have to put in place further barriers to prevent the occurrence of accidents and the industry major players will have to strongly invest in recruitment and formation to assure availability of competent crew members.
We are progressing into powerful vessels, equipped with the latest technologies, able to operate in hostile and demanding environments. And the future of the Offshore Industry depends, in great measure, on their safe operation by capable crew members. (Agus Salim -05)