Petroleum industry vessels

All vessels entering Australian waters, regardless of their size or frequency of visits, pose a biofouling risk to Australia’s marine biosecurity.

This factsheet provides an overview of the biofouling risk posed by vessels operating in the petroleum production and exploration industry and information on how this risk can be minimised.

Typical vessel types in this sector include offshore support vessels, mobile offshore drilling units, crew transfer vessels and pipe laying vessels. [See a comprehensive list of petroleum vessels.]

Why are petroleum vessels a biofouling risk?

All vessels entering Australian waters carry marine species that have attached to vessel surfaces as biofouling. Some of these species have the potential to survive the voyage, establish viable populations and become invasive pests. The likelihood of a biofouling species of concern arriving in Australia in this way increases with the number of overseas ports visited and the length of time the vessel spends in each port or stationary at a location. It is further influenced by factors such as the type and age of antifouling coatings and the time since the last drydocking.

The petroleum vessel sector includes vessels such as support vessels, crew transfer vessels and seismic survey vessels that operate in a similar fashion to commercial vessels and have similar biofouling risk profiles. These vessels have antifouling coatings applied to hull surfaces and operate at speeds sufficient to prevent extensive build up of biofouling on exposed hull surfaces. However niche areas such as bow thrusters, sea chests, exposed piping, and propeller shafts and rudders may accumulate biofouling.

Other vessels typically spend prolonged periods at berth or at an off-shore location. Petroleum vessels such as drill platforms remain stationary for long periods but when relocated, are towed at slow speeds to new locations, frequently without prior cleaning.

This creates a risk of spreading accumulated biofouling species to new locations along the route. Vessels with work activities that cause sediments and biological material to become entrapped in equipment or that cause damage to antifouling coatings (for example through recovery of cables and mobile equipment, or through frequent contact with the seabed) are also prone to biofouling.

Managing the risk

The build-up of biofouling on vessels can affect travelling speeds, reduce efficiency and increase fuel consumption. Furthermore, the build-up of biofouling in seawater intakes and pipework can affect critical equipment such as engines and ancillary systems, including air conditioning systems, refrigeration systems and fire fighting pumps, all of which are essential for the safe and efficient operation of a vessel.

As a result, many vessels already have systems in place to reduce biofouling through regular and well-targeted application of antifouling coatings on exposed hull surfaces and other vessel hygiene practices such as treatment of internal seawater systems, regular inspections and in-water cleaning.

Continued vigilance in biofouling reduction practices, with particular attention to niche areas, will both improve the operational efficiency of vessels and help to protect Australia’s marine environment and industry.

Below are some actions that can help manage the biofouling risk posed by commercial vessels:

• assess the biofouling risk of the vessel prior to departing for Australia and take remedial action as necessary
• undertake regular inspections of areas most prone to biofouling, such as niche areas [see diagram below]. High-risk areas for biofouling include rudder propellers, sea chests, bilge keels, anchor locker and cable, bow and stern windlass and bow thrusters
• implement a regular schedule for maintenance and dry docking apply antifouling coatings best suited to the operating profile of the vessel, noting that niche areas may require specific coating system
• re-apply antifouling coatings well within the life-span specified by the manufacturer, paying particular attention to coverage of docking strips, niche areas and inside pipe openings and accessible internal areas
• regularly ensure marine growth prevention systems (MGPS) are operating efficiently and effectively. In the absence of a MGPS, ensure that other treatment options for internal seawater systems, such as manual dosing with chemicals or hot water, are undertaken regularly and effectively.
• inspect and clean vessels and infrastructure that have remained stationary for prolonged periods prior to moving to a new location.

For more information on how to reduce the biofouling risks on commercial vessels, refer to the publication National biofouling management guidelines for commercial vessels or email IMS Program.

Niche areas on a petroleum vessel where biofouling can accumulate. 

Illustration adapted from a diagram provided by Mermaid Marine Australia. Images courtesy of Ashley Coutts, Cawthorn Institute (bow thruster);
John Polglaze URS Australia, courtesy of Helix ESG (anchor locker and cable, sea chest and propeller)

Petroleum Vessels include:

• Accommodation vessels Diving support
• Crew transfer vessels
• Diving support
• Floating production, storage and offloading vessels and floating storage and offloading vessels
• Landing craft
• Mobile offshore drilling units including jack-up units, drilling barges and semi-submersible ships
• Offshore support vessels including utility support vessels, platform supply vessels and anchor handling tug supply vessels
• Pipe layer ships and barges
• Seismic survey vessels