Sonar Technology as a Control Option of Oil-Spill Risk due to Ship Groundings

1. Sonar Technology as a Control Optionof Oil-Spill Risk due to Ship Groundings Tzannatos, E. and Xirouchakis, A. Department of Maritime Studies University of Piraeus – Greece 4th International MASSEP Conference 30 & 31 May, 2013 - Athens - Greece

2. The Need: Why ? Ship groundings have been historically responsible for the loss of life and property at sea, as well as for the pollution of the marine environment. Almost 25 years ago, on the 24th of March 1989, the “Exxon Valdez” grounded on Bligh Reef, a well known navigation hazard, ruptured 8 of its 11 cargo tanks and spilled 11 million gallons of crude oil into the pristine waters of Prince William Sound. The coast of south-east Alaska became the setting of an oil spill accident which by the MARPOL amendment in 1992 brought about one of the most important regulatory changes in ship design, the double-hulling of oil carriers. Being purely a technical pollution prevention measure, it did not address the human error as the root cause of shipping accidents but aimed at the control of the grounding consequences. However in October 1989, in response to the HFE accident of 1987, IMO adopted the “Guidelines on Management for the Safe Operation of Ships and for Pollution Prevention” which became the stepping stone for the most important operational regulation on shipping safety, that of the ISM Code, which was introduced through the relevant SOLAS amendment in 1993. Despite the effort to improve ship’s bridge performance over the years by implementing various technical and operational measures, ship groundings continue to dominate the picture of shipping accidents. Amongst them, the most recent of ‘M/SCosta Concordia’ in the Tyrrhenian Sea and ‘M/VRena’ of the coast of New Zealand have reiterated the importance of navigational errors and the need to maintain the impetus for improved ship bridge control.

3. The Objective: What ? In enhancing shipping safety, the application of Formal Safety Assessment (FSA) as “a rational and systematic process for assessing the risks associated with the shipping activity and for evaluating the costs and benefits of options for reducing these risks” has been institutionally (i.e. by IMO) acknowledged to be a most appropriate course of action. To this extent, the present work aims at submitting the hull mounted forward looking sonar (FLS) technology to the FSA “test” for assessing its suitability as a Risk Control Option (RCO) of powered groundings, whilst the case of oil carriers was considered to be of particular importance because of the high contribution of groundings to the accidental (i.e. large scale) pollution of the marine environment caused by these ships.

4. The Method: How ? An adaptation of: FSA

5. Oil Spill Risk Data (oil carrier groundings & contacts in 2004-2007) Sources: International Tanker Ownership Federation Limited database, Lloyd’s Casualty Database and Intertanko Casualty reports database.

6. Oil Spill Risk Data (oil carrier hard groundings & contacts in 2004-2007)

7. Ship’s Obstacle Avoidance Capability (as a function of FLS detection range) A ship will avoid the obstacle ahead provided that within the FLS detection range will be possible to accommodate: a) the circlemanoeuvre, b) the response of the bridge crew to the verified obstacle detection and c) the obstacle detection verification, according to: RN ≥ (TM + TH + TN) x VS where, RN = FLS detection range (m) VS = ship’s speed (m/s) TM = time for circle manoeuvre (s) TH = time for bridge crew response (s) TN = time for obstacle verification (s) Assuming that the time, TM, required to sail the “advance” distance of the circle manoeuvre is given by: TM = k x (LS/VS) where, K = circle monoeuvre coefficient (=4) LS = ship’s length (m) a ship will be able to avoid the obstacle ahead provided its length, LS , follows the expression: LS ≤ ¼ x [RN – (TH x VS) – (TN x VS)] For the maximum commercially available RN = 900 m and assuming TN = 5.1 s, TH = 10 s and VS = 7.2 m/s (14 knots), the FLS is technically effective for all oil carriers up to and including the handymax category. For the Aframax (LS=250m), Panamax and Suezmax (LS=300m) and VLCC (LS=340m), the minimum FLS detection range for obstacle avoidance is 1108, 1295 and 1457 m, respectively. Source: ABS (2006).

8. Ship’s Obstacle Avoidance Capability (as a function of FLS System reliability)

9. Criterion of FLS Acceptance • The difficult part of setting the environmental criterion for the acceptance of any RCO (incl. FLS) is to define and evaluate the Cost of Averting a Ton of Spilled oil, CATS (MEPC 62; MSC 91). The work by Kontovas and Psaraftis (2009) and Psaraftis (2008) is most informative on the challenges involved in this issue. • For the purposes of the current analysis, it is assumed that: • CATS ≤ F x Spill Cost • where, • F = assurance factor reflecting society’s WTP for prevention rather than cure • = 1.5 (Skjong et al., 2007; Vanem et al., 2008). • Spill Cost = damage cost + clean-up cost • CATS = 80,000 $/ton (Psarros et al., 2011) • For FLS acceptance: CATS ≤ ΔC / ΔR • where, • ΔC = Cost of FLS ($/Ship) • ΔR = Oil Spill Risk Reduction offered by FLS (ton/ship)

10. Cost of FLS (detection range 900 m) ΔC (NPV) = FLS Cost in NPV IC = Initial FLS Cost = 172,000 $ YC = Yearly FLS Cost = 3812 $ i = number of year y = duration of investment = 25 years r = discount rate = 5% Oil Spill Risk Reduction (Handy Category) ΔR (tons/ship)= ΔG (%) x Existing Risk (tons/ship-year) x remaining ship’s life (years) = 0.703 x 0.084 x 24= 1.48 tons/ship

11. Technical and Economic Effectiveness of FLS System

12. FLS Cost as a Function of Detection Range A technically and economically effective FLS for all ships will require an increase in detection range by 62%, to be offered at a 25-fold increase in cost !!!!!!

13. Conclusions Technical Effectiveness • For the maximum commercially available detection range of 900 m, the FLS is effective for obstacle avoidance by all ships up to and including the HANDY category. • The minimum FLS detection range for obstacle avoidance by SUEZMAX and VLCC must be 43.9 and 61.9% higher than the maximum commercially available FLS range, respectively. Economic Effectiveness • The FLS is economically ineffective for the reduction of oil spill risk associated with all ships of the HANDY category. It would have been cost effective for this ship category if the cost of FLS was 46.1% lower. • The FLS would have been economically effective for the reduction of oil spill risk associated with SUEZMAX and VLCC provided its cost was lower than 1.33 and 5.58 million $ per ship.

14. References • ABS (2006) Guide for vessel maneuverability. American Bureau of Shipping, ABS Plaza, 16855 Northchase Drive, Houston, TX 77060 USA. • Kontovas, C. and Psaraftis, H. (2009) Formal Safety Assessment: A Critical Review, Marine Technology, 46:1, pp. 45–59 • McGrecor, J., Moore, C., Downes, J. and Aksu, S. (2009) Evaluation of the Environmental Risk of Aframax Tankers, WMTC 2009, Jan. 21-24, Mumbai, India. • Psaraftis, H. (2008) Environmental Risk Evaluation Criteria. WMU Journal of Maritime Affairs, 7:2, pp. 409–427. Psarros, G., Skjong, R. And Vanem, E. (2011) Risk acceptance criterion for tanker oil spill risk reduction measures. Marine Pollution Bulletin, 62:1, pp. 116–127. • Skjong, R., Vanem, E., Endresen, O. (2007) Risk Evaluation Criteria, SAFEDOR Report:, SAFEDOR-D-4.5.2-2007-10-24-DNV-RiskEvaluationCriteria-rev-3.0. • Vanem, E., Endresen, O., Skjong, R. (2008) Cost effectiveness criteria for marine oil spill preventive measures. Reliability Engineering and System Safety, 93:9, pp. 1354–1368.

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