DeepWater Horizon spill begets OSRV surge

Across the globe, this focus has promoted planning, gap analysis, training and a wide range of equipment orders, from the very basic boom to complete Oil Spill Response Vessels. (OSRV)

On the latter, organisations have been looking for vessels that can undertake a wide variety of anti-pollution activities and also be an effective multi-role craft outside the OSR operations. The requirements are for simple, robust and reliable boats with a variety of features that can withstand the rigours of the marine environment. Typically, many companies now prefer and opt for steel built boats because they can withstand the everyday bruising of multirole operations better than other, lighter material builds. In addition, steel can be easily repaired without the need for specialist equipment or skills, making it ideal for the remote operations.

Due to the variety of roles the vessel will be called upon to perform, catamaran hulls have edged to the forefront of the standard design and build. Cats can offer the beam and stability demanded in both OSR activities and multi-roles. For example, the vessel should be able to deploy and recover a wide range of boom systems. Ideally this should also be from the stern of the boat, offering a stable, wide and open platform.

Other requirements include, but are not limited to integral or built-in skimming systems; dispersant spraying; debris collection; the operation of other OSR equipment; onboard oil or chemical storage; a jib crane for general lifting duties, and propulsion systems that are not overly burdened by electronics.

The range of DESMI Ro-Clean Pollcats (POLLution – CATamarans) has been specifically designed and manufactured to meet the above demands and more. With a range of steel boats from 10m to 24m in length, the Pollcats offer a variety of platforms which can be bespoke outfitted as required.

By utilizing the cat hull, DESMI has integrated a dynamic rope mop oil recovery system that can be raised and lowered between the hulls. This feature allows for the vessel to travel up to five knots while maintaining near zero relative velocity between the rope mops and the water. Typical boom or cusp recovery systems are restricted to below one knot recovery speeds, which can be easily upset by currents, tides, and even the speed of the vessel at tickover on the main engines. The DESMI mop system overcomes these issues and can operate at a claimed five times the speed of conventional OSR vessels.

The recovered pollutant can be stored in the high capacity tanks mounted in each hull. The tanks are linked and an onboard, positive displacement pump allows for tank-to-tank and ship-to-ship operations. The Pollcats can also carry a quantity of DESMI Ro-Clean flexible temporary storage tanks which can be deployed, filled and marked ready for other vessels to recover, allowing the Pollcat to remain on station.

The DESMI Ro-Clean Pollcat is usually fitted with 6.5m dispersant spray arms with in-built pumps and dispersant tanks. This allows the operator to use either neat or dilute dispersant and deploy over an impressive swath. The system can be operational within minutes, making quick, first response a reality where dispersant use is approved.

Below decks, 160 hp diesel-driven hydraulic power pack not only powers the unique mop system but the jib crane and capstan. Sufficient capacity is availble to power other skimmers, pumps and booms through deck connections controlled either through a bridge mounted console or by a remote unit also mounted on deck. The Pollcat bridge is mounted some 2.5m above the deck, making for an excellent command centre during all activities.

The Pollcat can also recover surface debris. By lowering a discreet debris basket sitting below deck and between the hulls, the vessel can simply scoop and recover into the basket. The latter can be emptied and positioned by the onboard jib crane.

The Pollcat is offered with Doosan diesels as standard, with power ratings up to 360 hp. With an engine in each hull, the owner has choices of operational modes.

Portland UK based Manor Marine have been building DESMI Ro-Clean Pollcats for Danish company DESMI for a number of years and over the last 12 months has delivered five vessels to destinations as diverse as West Africa and South America.