Navigation standards slammed - Tanker Operator

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p35-38.qxd 09/05/2006 12:07 Page 2 TECHNOLOGY EMERGENCY RESPONSE by. He could see what was happening and he approached quickly, threw the men a line and towed them clear of the burning crude. Vessel stationary It is worth noting that the tanker's engine was shut down before the vessel was fully abandoned. The Limburg was then stationary and soon became enveloped by fire - which spread rapidly from midships to foredeck. There are several lessons from the Iran- Iraq war of relevance in this situation. First, it is important to have at least two tugs in attendance. Two, this is the absolute minimum for a successful tanker salvage: one tug to connect up and slow tow, while the other firefights and boundary cools. For example, in the case of the Thorshavet, the Ribut was soon joined by a second Wijsmuller tug, the Amsterdam. When an oil outflow ignites it is absolutely vital to keep the casualty moving! This principle also applied in the Limburg situation. With only one tug immediately available, the best response - given that the tanker still had propulsion - would have been for the tanker to go full ahead with hard rudder. A 'quick getaway' in a turn would have soon left that burning oil behind. As the Limburg firefighting operation developed, there were echoes of the Thorshavet salvage 18 years earlier. Once again, a manhole was opened to inject foam. We used an oxblood product. This type of foam has have been around for many years, but it is extremely effective. Over a period of days more tugs and salvage equipment reinforced the Limburg operation. This allowed the salvage team to step up cooling, further reduce steel temperatures and better protect the undamaged tanks. They also brought the tanker's own firefighting systems into operation. We then succeeded in extinguishing the main fire in the damaged tank. This good news was tempered by the increased explosion risk. The huge hole in Limburg's side reminded me of the Thorshavet damage. Both casualties were particularly vulnerable at this stage. Steel temperatures were still high and there was much concern about the condition of the adjacent tanks. Every tanker firefighting operation By stopping, the Limburg became even more endangered. reaches this delicate stage. The main priority, in the case of the Limburg, was to restore the tanker's inert gas system, as soon as possible. With this accomplished, we began inerting laden tanks, followed by undamaged empty tanks and, finally, the damaged spaces. We also transferred oil/water mix from damaged tanks to an intact space, in order to reduce pollution. During the early stages we had planned to pump, to induce a modest port list and bring the hole in the starboard side above the waterline. In the event, however, we ballasted down, to bring the damage TRUSTED WORLD WIDE BRUNVOLL – the single source supplier of thruster systems Refined and proven concepts teamed up with supreme technical solutions ensures low life cycle costs BRUNVOLL – manufacturer of ● Tunnel Thrusters ● Azimuth Thrusters ● Low-Noise Thrusters ● Thruster Control Systems Another successful story... The «Viking Avant» – equipped with Brunvoll Tunnel Thrusters Brunvoll Retractable Azimuth Thruster under the water and create a water lock. This was achieved and the space could be inerted using special, water-driven equipment. As this salvage unfolded, Limburg was under a slow tow (1.5-2 knots) parallel to the coast. In these situations the ideal tow speed is found by trial and error as it will depend on so many variables -not least the behaviour of the casualty on the tow, the weather and sea state. Later, with firefighting and cooling completed, the Limburg was able to proceed under her own power (but with tug escort) to Fujairah, for a ship-to-ship cargo transfer. In conclusion, the key lessons from the shipping attacks during the Iran-Iraq war - and the infrequent major tanker fires of subsequent years - should be clear to all. Enormous firefighting and cooling capacities are essential when confronting large crude oil fires. Plenty of foam is needed, not only to extinguish the fire, but also for possible defensive use during the earlier phases of firefighting. A new factor in recent years, was the proliferation of double hulled tankers. The Limburg was a virtually new doublehulled vessel. Following the initial explosion, there were subsequent explosions in adjacent tanks. At first, it was thought that the terrorist attack was continuing. It appears, however, that the subsequent explosions may have arisen due to the flash-off of coatings, which created a dangerous atmosphere in the void space. There may be differing technical opinions on this last point, but the central fact remains: the void space is not inerted! In a fire situation, oil heated to 200-300 deg C could flow into the space between the hulls, rapidly creating an explosive atmosphere. Such situations present the salvor with extraordinary challenges and the prospect of working in an even more dangerous environment. TO telephone + 47 71 21 96 00 fax + 47 71 21 96 90 e-mail: office@brunvoll.no www.brunvoll.no *by Bram Sperling, general manager, operations, SvitzerWijsmuller Salvage TankerOperator May/June 2006 page 36
p35-38.qxd 09/05/2006 12:07 Page 3 TANKER Operator Napa unveils emergency response software Finnish software house Napa has developed NAPA Emergency Response (NAPA ER), which is claimed to be a powerful tool to help ship operators, national and coastal administrations, classification societies and salvage companies to quickly decide on the best recovery action when a ship is in a hazardous situation. NAPA ER has been developed to meet the demands of easy loading and damage analysis, and to enable fast technical support to get to a vessel in trouble. A land-based technical support team is already required for tankers sailing in US waters (OPA 90). The demand for such support is expected to grow at an increasing pace. By using the software, an operator will be able to prepare proactively for damage scenarios, quickly test recovery strategies and provide positive leadership based on sound technical information. NAPA ER integrates a number of in-house functions into a single intuitive achieve a desired floating position, while keeping the ship within stability or structural constraints. The NAPA ship model generated, whether during the design process, the plan approval process or for on board NAPA, can be used directly in this marine salvage engineering software; no special conversion or preparation of the database is needed. Ship models can be stored locally in the NAPA system and accessed through the intuitive interface. Primarily developed for organisations involved in emergency response and salvage work, such as classification societies, salvage companies, shipowners and operators, authorities and consultancies, NAPA ER is also claimed to be an excellent tool for 'browsing' the ship model and examining stability and strength related issues. This makes it a useful tool also for, among others, stability training purposes and ship designers wanting to study the behaviour of a given ship model. The grounding and breach are defined; various quantities including oil flow discharge and grounding force are calculated by NAPA. NAPA ER has been developed to meet the demands of easy loading and damage analysis, and to enable fast technical support to get to a vessel in trouble. ..The demand for such support is expected to grow at an increasing pace. graphical user interface (GUI), giving access to the necessary stability, loading and longitudinal strength functions needed for emergency response and salvage operations. Damages ranging from flooding to structural failure and groundings can be modelled efficiently, claimed Napa. Initial loading conditions can be imported from the ship's on board Napa loading computer or quickly defined in the NAPA ER user interface. Recovery strategies using any combination of techniques - such as cargo transfer, shifting of liquid loads, pumping, mass loading, over-pressurisation and under-pressurisation - can simultaneously be analysed as serial or alternative actions. Different scenarios can be tested using a logical tree structure of dependent actions and the results - for instance, cargo outflow, stability, grounding force, shear force and bending moment - can be studied throughout the tidal range. Multi-objective genetic algorithms can be harnessed to quickly evaluate and optimise loading combinations in order to In October 2004, the IMO Marine Environment Protection Committee (MEPC 52) proposed amendments to Regulation 26 of MARPOL 73/78 Annex I. These proposals specified that all new and existing oil tankers of 5,000 dwt and above should have access to computerised, shorebased damage stability and residual structural strength calculation programs. These proposals have now been adopted and will enter into force on 1st January 2007 as Regulation 37 of the revised Annex I. The use of NAPA ER will help ensure compliance with these new regulations, the company said. Future development Future software development plans include functions for calculating residual strength on the basis of the extent of the structural damage and time domain calculation for loading and flooding, in addition to the already existing time domain calculation of the influence of tide. TO TankerOperator May/June 2006 page 37
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Navigation standards slammed - Tanker Operator

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