Markleen Oil Spill Booms and Skimmers for Thailand

Markleen publishes capacity data for every product line SATU supplies. The four tables below give the figures a port, terminal or vessel operator needs when sizing an oil spill response inventory: boom freeboard and draft by class, skimmer recovery rate and draft, storage volume, and the sweep system geometry. All figures are taken from the current Markleen datasheets.

Containment boom classes and capacities

Freeboard and draft are the two numbers that decide whether a boom holds oil. Freeboard is the height of the barrier above the waterline: it governs splash-over, so it must be sized against the wave height at the site, not against the depth of the water. Draft is the depth of the skirt below the waterline: it governs entrainment, the loss of oil dragged underneath the boom by current or by towing speed. A boom too shallow in draft will lose oil in a tidal stream even in flat water, and a boom with too little freeboard will lose oil over the top in a chop. Total height is freeboard plus draft plus the float section, and it drives reel and storage volume. Section length sets how many connectors a deployment needs and how long it takes to lay a given length. The Beaufort figure is the sea state each class is designed to work in; select the class from the worst condition the site can present, not the average one.

ECOSAFE booms use 3 m buoyancy chambers; ECOMARINE booms use 5 m chambers and are supplied in continuous lengths of up to 400 m for reel deployment. Total boom length required at a berth is set by the vessel, not by the boom class: at 25 m per section, a 250 m run is ten sections plus connectors.

Skimmer recovery capacities

Maximum recovery capacity is a ceiling, not a working rate. It is measured with the pump and cartridge at full speed on a thick, continuous oil layer. In a real spill the throughput you get is set by the encounter rate (how much oil actually reaches the skimmer head, which depends on containment, current and how the boom is towed) and by the viscosity and emulsification of the oil, which change hour by hour as the slick weathers. Plan on a working rate well below the datasheet maximum, and size the pump, hose and receiving tank for the maximum so the head is never the bottleneck. Max draft matters where the water is shallow or the skimmer works inside a boom pocket alongside a quay. Weight decides whether two people can carry the unit or whether a crane is needed, which in turn decides how quickly it can be in the water. All four MultiSkimmer sizes accept brush, drum or disc cartridges, changed without tools, so one hull covers light diesel through to heavy fuel oil.

Recovery capacity is the skimmer head rating, and the delivered throughput is limited by whichever is lower, the head or the pump supplied with it. The MS 30 is the one model in the range where the pump governs: its integral Vogelsang lobe pump is rated 33 m³/h at 1,100 rpm against a 46 m³/h head rating. Weights for MS 30 and MS 60 include the pump; MS 10 and MS 20 do not, and their external pumps add 14 kg and 28 kg respectively. For the Shallow Water Skimmer, Markleen publishes no recovery rate, draft or weight for the vacuum head itself: the 30 m³/h and 95 kg are the Selwood Spate PD75 pump with its Yanmar diesel engine, and the hydraulic-motor version of that pump weighs 43 kg.

Temporary storage capacities

Storage is the constraint that most often stops a recovery operation. A skimmer rated at 46 m³/h fills a 15 m³ tank in under twenty minutes of good encounter, and recovered oil is rarely pure oil: it arrives as an oil and water mixture, so the volume you must hold is larger than the volume spilled. When storage is full, skimming stops until a vacuum truck or a barge arrives, and in that interval the slick keeps spreading and weathering. Size storage against the time it takes to get a road tanker or receiving vessel to the berth, not against the size of the spill. ECOBAG units are towable and float, so they can be filled at the skimmer and moved; ECOTANK units are framed tanks for a deck or a hardstanding; ECOPOOL units are pop-up pools sized in litres, for drips, decanting and equipment washdown rather than for bulk recovery.

ECOBAG maximum tow speed is 8 knots empty and 5 knots full. ECOTANK units are supplied with a roof cover and a ball valve with a 2 inch male camlock coupling.

Sweep system configuration

A sweep system is for the case where the oil is moving and the response vessel has to go to it. A containment boom moored across a current holds oil only while the current stays below the speed at which oil is entrained under the skirt. Above that, the oil escapes. A sweep system solves this by moving with the slick: a U-shaped boom is held open by an outrigger arm on one side of a vessel, so the vessel sweeps a fixed mouth width through the water, concentrates the oil hydrodynamically at the apex, and presents it to a skimmer at a much higher encounter rate than a static boom can. The class is used for open-water and offshore work, for large-area slicks, and wherever one vessel has to cover ground rather than defend a fixed line. The specification below is the Markleen Sweep System. For high-speed sweeping in current, the NOFI Current Buster series has a built-in oil and water separator and is covered, with its own capacity figures, on the NOFI Current Buster page.

The sweep boom uses inflatable floats independent of the outer fabric, so a punctured float can be replaced without replacing the boom. The outrigger arm is aluminium, splits into two 3 m halves, and swivels horizontally and vertically at the vessel side. The Sweep System datasheet gives no tow speed for the assembled system, but it names the Markleen Z 1400 HD as the boom in the 1400/23/6 configuration, and the Z Series datasheet rates that boom at 6 knots tow speed and 2 m maximum wave height.