Minding the Helm Marine Navigation and Piloting (1994) / Chapter Skim
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4 RISK, THE OPERATING ENVIRONMENT, AND SAFETY
4 RISK, THE OPERATING ENVIRONMENT, AND SAFETY
Pages 159-184
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From page 159... ...
Risl< in the complex marine operating environment has increased significantly9 because substantial increases in the costs of marine casualties that result in pollution have not been accompanied by a corresponding decrease in the probability of accidents. The probability of accidents might be reduced through improvements to organizational structure and processes9 professional development operating practices9 and technology.
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From page 160... ...
The third section examines safety performance. Trend analysis practices in marine transportation are characterized, and causal factors in marine accidents are discussed.
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From page 161... ...
Risk analysis has been described as comprising three primary components: risk assessment, risk management, and risk communication (Figure 4-1~; (Balson et al., 1992; Covello, 1987; NRC, 1989~. Risk assessment is the qualitative or quantitative evaluation of the environmental, health, operational, or economic risks that may result from some process, activity, or event: To assess human health risks, for example, one would combine information about a group's exposure to risky substances with information about the effects of those substances on the human body to derive an overall characterization of the risks a group faces (North and Yosie, 1987)
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From page 162... ...
In this sense, risk management is a specific application of decision analysis. Risk communication includes all purposeful exchanges of information about health, environmental, or economic risks between interested parties.
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From page 163... ...
For reference classes where the rate of past occurrences has been too low to construct a statistically relevant and significant knowledge base, methods have been developed that provide reasonably accurate estimates of accident probability. These methods use structured approaches to model the operations involved and, through the use of tools such as hazards and operability studies, failure modes and effects analyses, fault trees, and decision trees, provide quantitative estimates of the probability of accidents.
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From page 164... ...
Many aircraft passengers are familiar with these statistics, but the personal sense of danger is stronger aboard the aircraft than when using ground transportation. This example illustrates a disparity between probabilistic risk and perceived risk based on a subjective sense of the likelihood of bad consequences, not the relative value (cost)
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From page 165... ...
Improvements in organizational structure, professional development, operating practices, and technology are the principal methods for reducing the probability of accidents. Major advances to achieve such a reduction may require fundamental changes in navigation and piloting practices, administration and technologies, operational procedures employed aboard vessels, marine traffic regulation (including the setting of limits on vessels or operations in certain areas)
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From page 166... ...
, other vessel traffic, and environmental conditions. Mariners, their vessels, and cargoes are the immediate recipients of the physical consequences of accidents, regardless of the economic costs, so operational risk is emphasized over economic risk in terms of perceived physical threats and abilities to avoid or counter these threats.
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From page 167... ...
(Columbia River Bar Pilots) Assessing Risk in Marine Transportation Although there are two primary approaches to assessing risk and human error, there is no widely applied methodology for assessing risk or accepted approach for assessing safety performance in marine transportation.
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From page 168... ...
, including the waterways management system and management aboard each vessel (Cahill, 1983, 19851. Further, causal analyses of human error and risk analyses, and quantitative as well as qualitative approaches to assessing risk, are also receiving increased attention.
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From page 169... ...
and bulk movement of crude oil and petroleum products in Alaska's Prince William Sound and in Washington State's Puget Sound and the San Juan Islands. But some coastal states are becoming more active in addressing local and regional interests in marine safety.
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From page 170... ...
ARPA also has not yet been proven effective for navigation requiring constant maneuvering, as is required in sections of the lower Mississippi between Pilot Town and Baton Rouge, in Kill Van Kull and Arthur Kill (New York) , in the Calcasieu and Houston Ship Channels, and in similar waterway configurations (Box 4-2~.
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From page 171... ...
..'.':'.' ~: :.::.:.,::.',':::'.::::: ::::::',:,:,: :.: :,:.:,:,.:,: ' . '2,,: ' .' ,': - ': ~' ': Sandy Hook pilot boat in winter conditions pushing to meet a waiting ship off of Staten Island, New York.
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From page 172... ...
. Figure 4-2 reflects the historical casualty rates for VTS-addressable casualties per 100,000 transits, as recorded in Coast Guard and NTSB investigations of marine accidents between 1979 and 1989, and in data on waterborne commerce accumulated by the U.S.
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From page 173... ...
The complex includes three prominent "mixing bowls" with converging and conflicting traffic patterns and strong tidal currents in Hell Gate and Kill Van Kull (Maio et al., 1991; Young, 1992, 19941. There is a general lack of understanding, even within the marine industry, of the complexity of port, waterway, and river operating environments; the nature and variability of risk factors that are present; and vessel behavior in shallow water and confined, asymmetrical channels.
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From page 174... ...
, prepared for this report, discusses the various forces that shiphandlers must understand in order to maneuver their vessels effectively while in pilotage waters. These forces include wind, current, and wave effects in open sea and shallow water conditions; shallow water effects on inertia, maneuverability, heading stability, resistance to headway, stopping distance, and squat and sinkage; and narrow channel effects on vessel control and vessel interactions.
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From page 175... ...
It may be possible, however, to reduce the number of such evolutions through such measures as regulation of marine traffic, although this could cause significant economic effects (Box 4-41. Transit Considerations Risk is significantly affected in piloting waters by the nature of marine commerce and the vessels engaged in it, as well as cargoes carried, length of exposure, and navigation support available both on and off the vessel.
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From page 176... ...
77d 111 T:~lll+lIl4+llll~m~llll~l+lSi((llllinl+ll~illllll-_ll 111 1~ 1 I1~ - -.
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From page 177... ...
(U.S. Coast Guard)
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From page 178... ...
The implication is that technological advances can ameliorate some risks while introducing others. ISSUES TO BE ADDRESSED BY QUANTITATIVE RISK MANAGEMENT Data Limitations Considerable marine safety data are collected under protocols established by the Coast Guard.
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From page 179... ...
to provide navigation information increases the communications load on the bridge team and pilot, even if the VTS assumes or reduces radio guards (monitoring' on other government-required frequencies. Voice-radio use increases during periods of reduced visibility.
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From page 180... ...
Use of shore-based navigation support systems such as VTS is growing slowly but cannot replace effective performance by masters, bridge personnel, and marine pilots. The effectiveness of shore-based systems in offsetting human errors such as those found in collisions, rammings, and groundings is an open question.
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From page 181... ...
But underlying causal factors, particularly deficiencies in professional development and human performance, are difficult to discern, even to trained marine accident investigators. Casualty data have not been adequate to support this task (NAS, 1973, 1976, 1981; NRC, 199Oa, 1991a)
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From page 182... ...
Alternatives for development of data on risk and exposure that are identified in the following sections are intended to supplement recommendations of prior NRC reports. Establish a Near-Miss Reporting System Valuable early insight on actual or potential trends or problems can-be obtained through routine recording and analysis of data on: · marine accidents; · unusual events (such as loss of propulsion, steering system failures, and near misses that do not qualify as reportable casualties)
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From page 183... ...
Some of this information already is collected in varying degree but is not widely used to plan or guide traffic regulation operations or safety programs. This information could be combined in a reliable data base, such as the Coast Guard's prototype exposure data base, which would facilitate identification and analysis of risk and exposure across a wide range of variables.
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From page 184... ...
Such an effort would require coordination among worldwide regulatory, classification, and insurance interests to ensure that the data base was large enough to provide statistically significant results. Implementation would require long-term commitment of resources by the Congress, the Department of Transportation, and the agency designated to conduct the program.
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