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Hull biofouling – key recommendations Marine invasive species infestations are a major threat to the world’s oceans and to the conservation of biodiversity. It can be triggered by marine hull biofouling, the accumulation of aquatic organisms on ships’ hulls, which are then transported around the globe and inadvertently deposited in non-native waters. Here, they can become invasive, out-competing native species and multiplying into pest proportions. Hull biofouling also has the effect of producing additional friction (hydrodynamic drag) on the vessel, which can increase fuel consumption by as much as 35 per cent. In other words, good biofouling management can also be an effective tool to enhance energy efficiency and reduce air emissions from ships.
The 2023 Guidelines for the control and management of ships’ biofouling to minimize the transfer of invasive aquatic species (Biofouling Guidelines) are an update to and replacement of the 2011 guidelines. They are intended to provide a globally consistent approach to the management of biofouling, and include detail on ship design, selection of antifouling systems, hull cleaning and maintenance, among other issues. Strict enforcement regimes are in place in nations like Australia with very sensitive marine ecosystems, and ships can be ejected from territorial waters as a result of biofouling. A recent example saw a cruise vessel evicted from New Zealand waters, and later denied entry to Australian ports, due to marine biofouling on her hull. She was forced to dwell offshore for several days while professional divers were dispatched to clean the hull. Passengers onboard were later paid compensation and several port calls were missed.
Shipowners should install an AFS in all submerged surfaces on a ship where biofouling may attach. Various AFS are designed for different ship operating profiles, some suitable for hull and some for niche areas. Thus, shipowners, ship operators and shipbuilders should obtain appropriate technical advice when selecting a system. AFS manufacturers are best suited to provide advice to ensure a suitable system is applied, reapplied, installed or renewed.
Every ship should have a ship-specific Biofouling Management Plan (BFMP) under the responsibility of owners, operators and masters. A BFMP may require information from naval architects, shipbuilders, shipowners, AFC and Marine Growth Prevention System manufacturers, Class, and suppliers. The purpose of the BFMP is to contribute to the aim of maintain a recommended fouling rating of <= 1. The BFMP should include:
Inspections The guidelines provide scope for hull inspections on a schedule based on a ship-specific risk profile. Inspections by organisations, crew or other competent personnel at regular intervals: Performance monitoring of hull/fuel performance during ship operation should identify whether there may be an increased risk of biofouling accumulation. When monitoring identifies a possible increase in biofouling accumulation, the ship is at a higher risk level which should lead to contingency actions. A contingency action plan may include measures which are ship-specific and relevant for the monitoring parameters. In general, it will recommend proactive actions, corrective actions (such as maintenance or other repair plans) and inspections.
A Biofouling Record Book (BFRB) should be retained on board for the life of the ship. It could be maintained physically or electronically, and should record details and reports of all inspection and maintenance activities to be undertaken for all hull and niche areas:
Importance of prevention
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LMB-BML 2007 Webmaster & designer: Cmdt. André Jehaes - email andre.jehaes@lmb-bml.be
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