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103 Evaluating and ranking risks is a well-established method to address dangers and hazards that can arise from industrial and commercial activities, includ- ing transportation. Risk assessment is also a useful method for evaluating and choosing the appropriate response to situations that are unique, or at least variations on a theme. For DUKWs, risk assessment avoids the likeli- hood that a âone-size-fits-allâ approach will unnecessarily increase costs for some DUKW operators, while leaving other hazards unmitigated. Having information on the relative significance of risks from various hazards will provide the United States Coast Guard (USCG) an opportunity to focus its regulatory efforts. In addition, USCG already utilizes risk assessment when determining the level of inspection intensity for various small passenger vessels.1 For all these reasons, the committee considers risk assessment as the central strategy to identity and mitigate safety hazards associated with DUKWs and their operations. Before listing the recommendations, this chapter presents the commit- teeâs summary findings on which factors make for higher risk operations. These findings then inform the recommendations targeting the use of risk assessment and the mitigation of hazards presented in each of the safety categoriesâflooding, operating areas, restrictive canopies, life jackets, and safety operations. 1 USCG Work Instruction CVC-WI-028(1), 2021, Small Passenger Vessel Risk Based Inspec- tion Program, issued June 14. https://www.dco.uscg.mil/Portals/9/DCO%20Documents/5p/ CG-5PC/CG-CVC/CVC_MMS/CVC-WI-028(1)a.pdf. 8 Risk Assessment and Recommendations
104 OPTIONS FOR IMPROVING THE SAFETY OF DUKW TYPE AMPHIBIOUS VESSELS The chapter concludes with an overview of risk-assessment tools that the committee has identified as especially appropriate for USCG use. The results of the committeeâs initial application of one of the tools, a sample output (HAZID Register) of the Hazard Identification (HAZID) method, is contained in Appendix C. SUMMARY OF FINDINGS ON HIGHER RISK OPERATIONS As presented throughout this report, the risks to passengers on DUKWs vary significantly depending on the type of DUKW vessel, the operat- ing area, and operator diligence. In order to identify appropriate areas for USCG regulatory and policy changes, the committee divided DUKW opera tions into two categories: higher risk and lower risk. The committee finds that the following characteristics of a DUKW vessel and its operation could result in a higher risk to passengers and higher likelihood of a major marine casualty event, even when the regulations in Subchapter T and the guidelines in Navigation and Vessel Inspection Circular 1-01 (NVIC 1-01) are followed. Some of the committeeâs recommendations, below, distinguish recommendations for higher risk versus lower risk operations. Fast Sinking Times Sinking times of 15 minutes or less are fast sinking and create greater risk of passenger injury and death. The risks inherent in low freeboard, the lack of a high-capacity bilge pump, multiple hull penetrations, engine air cooling vents, and operating areas exposed to high winds, waves, and traffic can easily combine to sink certain DUKWs in less than 15 minutes. Low Freeboard DUKWs having less than approximately 24 inches freeboard are at greater risk of rapid sinking, as compared to other open small passenger vessels of a similar size. WWII DUKWs and some Stretch Ducks have less than 24 inches of freeboard, but Truck Ducks generally have higher freeboard. Lack of High-Capacity Bilge Pump DUWKs that do not have a reliable, high-capacity bilge pump that can dewater at the maximum anticipated flow rate of a hull penetration can be quickly flooded. The Higgins Pump, part of the original design of the WWII DUKW, is not a reliable method of emergency dewatering.
RISK ASSESSMENT AND RECOMMENDATIONS 105 Multiple Hull Penetrations DUKWs that have shaft boot seals with or without restrictor plates, mul- tiple shaft penetrations, and multiple drain plugs have a higher risk of flooding. Engine Air Cooling Vents DUKWs that have air vent covers on the engine hood that lack a positive latching mechanism are susceptible to downflooding through these open- ings when encountering large waves. Vents that must be closed by the crew also present risks for downflooding. Potential for Exposure to High Winds and Waves DUKWs that operate on waters where high winds and high waves can occur, particularly high waves from rapidly developing squalls and storms, may be exposed to conditions that exceed those allowed by their Certificate of Inspection (COI). Given DUKWsâ maneuverability limitations, high winds can also make it difficult for a DUKW to safely escape severe weather. The current definition of âpartially protected watersâ may not cover all higher risk operating areas. Even waters considered âprotected watersâ may pro- duce high winds and high waves during rapidly developing storms if they have a long fetch in one direction. High Traffic Areas DUKW operation in areas with high levels of marine traffic or in proximity to shipping channels for larger commercial vessels can create greater risk of collision. Restrictive Canopies Canopies augment the risks arising from a vesselâs characteristics and operat ing areas. Canopies that have restrictive side curtains or closely spaced vertical canopy supports and that cover most or all of the passenger seats make emergency escape difficult and slow, creating greater risk. Such canopies also interfere with the wearing of life jackets during the tour or the donning of life jackets in an emergency. A canopy is considered to be a restrictive canopy unless its design has been demonstrated to provide the equivalent in safety to no canopy.
106 OPTIONS FOR IMPROVING THE SAFETY OF DUKW TYPE AMPHIBIOUS VESSELS LOWER RISK OPERATIONS AND RESERVE BUOYANCY DUKW operations that do not have any of the above higher risk factors can be considered lower risk operations. In addition, DUKWs fitted with reserve buoyancy such that they will remain afloat and upright in case of flooding can be considered lower risk operations unless they operate on partially protected waters or high traffic areas. Ultimately, whether the risks faced by lower risk operations are acceptable must be determined by more detailed review, but in recent years DUKW commercial operations that meet these criteria for lower risk operations have not experienced marine casualties with loss of life. COMMITTEE RECOMMENDATIONS The committee offers USCG the following recommendations, starting with the use of risk assessment for DUKW operations and then providing spe- cific recommendations to mitigate the hazards discussed in the chapters on flooding, operating areas, canopies, life jackets, and safety operations. All recommendations are specific only to WWII DUKWs, Stretch Ducks, and Truck Ducks. The recommendations should not be construed to apply to other amphibious passenger vessels or small passenger vessels. Use of Risk Assessment Recommendation 1: USCG should base updates to regulations and enforce- ment practices on the risks to passengers, operators, and the environment posed by each type of DUKW in its intended operating area. Because of the uniqueness of the DUKW design, the standard risk- abatement methodsâregulations and policiesâapplied to other small passenger vessels may not be adequate for the DUKW fleet. There are also significant varia- tions in design between DUKW vessels, so a âone-size-fits-allâ approach to the DUKW fleet under USCG supervision may be both inadequate for some DUKWs and overly conservative for other DUKWs. Assessing risk for each type of DUKW in its intended operating area also allows for the use of multiple, complementary methods to increase the survivability of the vessel and the persons on board. Recommendation 2: USCG should use a consistent risk-assessment meth- odology, applied at the industry level, to better understand the risks to passenger safety and to allow USCG to focus regulations and requirements on those DUKW operations that present the greatest risk.
RISK ASSESSMENT AND RECOMMENDATIONS 107 Risk analysis methodologies will help USCG better understand the great- est risks to passenger safety on DUKW vessels. There are standard risk- assessment processes used by industry to improve safety of higher risk operations. A method commonly used in the marine industry, the HAZID method, is described in more detail after the recommendations. The results of the committeeâs initial run of HAZID is found in Appendix C. Flooding and Survivability Recommendation 3: USCG should investigate requiring the installation of external inflatable bladders or buoyant floats, alone or in combination with internal flotation foam, to provide reserve buoyancy for DUKWs used in higher risk operations. These are likely to be the most viable options for keeping a DUKW afloat and upright in a fully flooded condition. Internal flotation foam alone, however, is not a viable solution. USCG should consider, during its investi- gation, the costs and required operational changes as well as the improve- ment to safety. Recommendation 4: To reduce the flooding risk from hull penetrations, USCG should investigate requiring DUKW operators to a. Permanently seal all drain plugs and valves that are not necessary for safe operation and maintenance of the vessel. b. Install carrier bearings. c. Install reliable bilge pumps of sufficient capacity to respond to flood- ing through the largest remaining through-hull penetrations, as per NVIC 1-01. Hull drain plugs and valves are a significant risk factor for flooding. Simi- larly, original drive shaft boot seals if not fitted with restrictor plates or modified with carrier bearings as detailed in NVIC 1-01 are another risk factor. As stated in the findings above, the Higgins Pump is not a reliable bilge pump. Recommendation 5: USCG should require vessel operators to demonstrate that adequate engine cooling is available for the expected operating areas and risks found in that area. Engine cooling hatches can be a source of downflooding into the engine compartment. To address this, some DUKWs have been fitted with keel coolers or alternate means to allow engine cooling with all hatches below the freeboard line closed while in the water. Vessels must be able to operate
108 OPTIONS FOR IMPROVING THE SAFETY OF DUKW TYPE AMPHIBIOUS VESSELS with cooling hatches closed if there is a risk of experiencing sea conditions that could cause flooding through these hatches. Operating Areas Recommendation 6: USCG should develop uniform guidance to assist Officers in Charge, Marine Inspection (OCMIs) in evaluating the suitability of bodies of water for DUKW operations. This guidance should consider the physical characteristics of the body of water, the presence of commercial and recreational traffic, the proximity of rescue craft, and access to âsafe refuge locationsâ (see Box 4-2) in the event of an emergency. Recommendation 7: USCG should develop requirements for equipment, training, and operations that leverage the National Weather Serviceâs (NWSâs) severe weather alert system to reduce the likelihood that a DUKW will encounter wind and waves that exceed its operating capabilities. For the duration of relevant NWS-issued warnings and advisories, the re- quirements should restrict DUKWs from conducting waterborne operations and mandate that already waterborne DUKWs proceed immediately to a safe refuge location. For the duration of NWS-issued watches, DUKWs should be required to follow a water route that allows them to navigate to a safe refuge location within a specified amount of time that incorpo- rates the likely amount of time between a warning being issued and severe weather occurring along the route. Vessels should be required to carry equipment that alerts the crew to severe weather watches, advisories, and warnings, and land-based operation centers should be required to monitor weather conditions and communicate weather information to their vessels. Operating manuals and personnel training should address procedures for severe weather. On very sheltered or benign waters that are not likely to be impacted by severe weather, it may be appropriate for the OCMI to exercise discretion on these requirements. USCG should consult with NWS when developing these requirements and any decision-support tools to be used by OCMIs. Restrictive Canopies Recommendation 8: USCG should require DUKWs in higher risk opera- tions to remove canopies or to adopt canopy designs that have been dem- onstrated to provide the equivalent in safety to no canopy.
RISK ASSESSMENT AND RECOMMENDATIONS 109 Considering the existing National Transportation Safety Board (NTSB) recommendations to remove canopies that impede passenger escape, the committee recommends that DUKWs in higher risk operations should either have no canopy or an easy-open, breakaway, shortened, or other canopy design that has been demonstrated to provide the equivalent in safety to no canopy. Designs for any canopy side curtains should also be demonstrated to provide the equivalent in safety to no side curtains. Side curtains that must be released by the crew do not provide the equivalent in safety to no side curtains. Side curtains designed to be opened by passengers should be demonstrated to provide the equivalent in safety to no side curtains before adoption. Signage and passenger orientation should include explicit instruc- tions on how to escape the vessel through any canopy or side curtain. For DUKWs in lower risk operations or that have means of supplemen- tal flotation, more complete canopies with easy-open side curtains may be suitable. Life Jackets Recommendation 9: USCG should consider making the wearing of life jackets mandatory during the waterborne portion of tours run by higher risk operations. Wearing life jackets will save lives, assuming the DUKW in crisis no longer has a restrictive canopy. Given the cramped conditions of the passenger compartment and that crew on board will likely number no more than two, the assumption that passengers will successfully don life jackets during an emergency is highly suspect. In addition, any policy that expects passengers to don life jackets once they are already in the water is strongly inadvisable. Recommendation 10: USCG should investigate the use of Type III life jack- ets in place of Type I life jackets. Type I life jackets, required on all commercial passenger vessels, are bulky and can be uncomfortable to wear. They can also restrict escape through a canopy not meeting the recommended standard in Recommendation 7. Type III life jackets are easier to don and wear for extended periods on a boat. The permitted routes for DUKWs are normally close to shore, so persons can be quickly rescued. The capabilities of Type I life jackets may not be needed.
110 OPTIONS FOR IMPROVING THE SAFETY OF DUKW TYPE AMPHIBIOUS VESSELS Safety Operations Recommendation 11: USCG should require that owners and operators develop an effective company operating and safety manual, as recom- mended in NVIC 1-01, that incorporates training, maintenance, and opera- tional standards as well as emergency response plans. The safety related parts of the manual could be incorporated into a com- pany safety management system (SMS) if USCG eventually requires SMS for all passenger vessels. Recommendation 12: USCG should require, and the OCMI should confirm, that the operating and safety manuals include procedures for monitoring changing weather conditions and adjusting operations accordingly. Recommendation 13: USCG should require, and the OCMI should confirm, that the operating and safety manual includes a discussion of the number of personnel and their duties. Regular crew drills are an important part of demonstrating crew knowl- edge of the operating and safety procedures included in the manual, or an SMS if eventually required. If only one crew member is allowed, this dis- cussion should justify how all safety functions are to be performed. Crew membersâeven if well trainedâdo not have the capability to assist all passengers in an emergency because they will be performing multiple roles. RISK-ASSESSMENT MATRIX Methodologies to identify hazards, evaluate their likelihoods and conse- quences, and develop ways to mitigate their risks are frequently used to assess and mitigate risks like those occurring in DUKW operations. The committee employs one such methodology that uses risk assessment to manage hazards in the marine industry. The following analysis by the com- mittee draws on its contents.2 In the marine context, a hazard is a condition that may lead to an un- desirable event. Typical hazards for DUKWs include external factors like storms or other boat traffic and internal factors such as the equipment and its known weaknesses, the number of personnel, the lack of safety equip- ment or training, or the maneuverability of the boat. Hazard events include flooding, but also stopping/stranding, collision, capsizing, or fire. 2 American Bureau of Shipping (ABS), 2020, âGuidance Notes on Risk Assessment Applications for the Marine and Offshore Industries,â May. https://ww2.eagle.org/content/dam/eagle/rules-and- guides/current/other/97_riskassessapplmarineandoffshoreoandg/risk-assessment- gn-may20.pdf.
RISK ASSESSMENT AND RECOMMENDATIONS 111 Risk is the product of consequences and likelihood. Consequences flow from the hazard event and are typically measured in injury and loss of life, property damage, environmental damage, and operability downtime. Likeli- hood is the chance or probability that a hazard will lead to an event, and it is typically expressed as a function of time, such as over a vesselâs operating life: for example, the likelihood of a propulsion failure leading to the vessel being towed once or repeatedly over its lifetime. Events may be produced by multiple hazards interacting, such as failed bilge pump coinciding with boat traffic producing waves. Multiple events may occur simultaneously or in quick succession, such as a propulsion failure stranding the boat fol- lowed by a storm. The risk guide defines âcontrolsâ as âthe measures taken to prevent hazards from causing undesirable events.â These can include physical changes to the boat and operational changes. In other contexts, âcontrolsâ are sometimes called âmitigationâ or âsafeguards.â Table 8-1 is an example of a typical risk-assessment matrix that defines likelihood, consequences in terms of their severity, and lower to higher risk. High-risk hazards are those that have the highest likelihood and highest consequences. The matrix indicates that these hazards must be mitigated to lower the risk to medium or low. Medium-risk hazards are acceptable with controls, which the responsible parties should verify. Low-risk hazards are acceptable: no mitigation is required. The matrix provides example definitions of consequences for passen- gers and the crew, environment, property damage, and operability down- time. âInsignificantâ and âlowâ consequence events would include those incidents that are not reportable to USCG because they do not involve first- aid injury and any damage is less than $10,000. âMediumâ consequence events would include those that require reporting to USCG because they involve a minor injury that requires professional treatment beyond first aid, damage greater than $10,000 but less than $100,000, and possibly notifica- tion to the National Response Center. âHighâ consequence events would include those with one fatality or major injury, damage above $100,000 but less than $1 million, and possibly require specialist cleanup. âVery highâ consequence events would include those that involve multiple deaths or major injuries, large-scale property damage greater than $1 million, and/ or other special outcomes such as an oil spill requiring third-party cleanup and long-term remediation. Once a risk assessment is completed, the results can be implemented with decision-support tools. For example, for the matrix in Table 8-1, OCMIs would still need a practical method for evaluating risk and risk mitigation for the DUKW operations under their jurisdiction. Checklists and other tools such as decision trees would still need to be developed.
112 OPTIONS FOR IMPROVING THE SAFETY OF DUKW TYPE AMPHIBIOUS VESSELS TABLE 8-1 Example of a Risk Matrix Consequences of Increasing Severity 1 2 3 4 5 L ik el ih oo d A L L L M M B L L M M H C L M M M H D M M M H H E M H H H H Definitions of Risk: H = High Risk: Must be mitigated with engineering and/or administrative controls to a hazard category of L or M and incorporated into the design and operation. M = Acceptable Risk with Controls: Should be verified that procedures or controls are in place. L = Acceptable: No mitigation required. Definitions of Likelihood Over the Life of the Vessel: A = Very Low: Conceivable, but extremely unlikely B = Low: Credible, but unlikely in the inspected DUKW fleet C = Medium: Likely to occur in the inspected DUKW fleet D = High: May occur about once on each vessel E = Very High: Event or similar may occur repeatedly on each vessel Definitions of Consequences of Increasing Severity: Level Passenger and Crew Environment Property Damage Operability Downtime 1 = None/ Insignificant No observable effects No observable effects < $1k Minimal 2 = Low First aid needed Non-reportable spill or release < $10k < 0.5 day 3 = Medium Lost time injury Reportable spill or release with company cleanup < $100k < 2 days 4 = High Single fatality or permanent major injury Reportable spill or release with specialist cleanup < $1M < 10 days 5 = Very High Multiple fatalities Requires long-term remediation > $1M > 10 days
RISK ASSESSMENT AND RECOMMENDATIONS 113 SAMPLE HAZARD REGISTER The HAZID technique is an example of a risk-assessment methodology that could be used to provide insights on which risks present the greatest dangers to DUKW passengers. Although it is not practical for USCG to carry out a HAZID for each DUKW operation under its purview, a general HAZID for typical risks, including those described in this report, across all DUKW operations, is feasible. Information on relative risk would provide USCG the opportunity to focus its regulatory efforts on the higher risks and continue with existing regulations for risks considered acceptable. The committee conducted a preliminary or sample HAZID analysis of DUKW vessels and the product, a Hazard Register, is found in Appendix C. Conducting a full risk evaluation using the HAZID technique typically requires holding a workshop attended by subject experts and knowledge- able persons. Although the committeeâs work is not a substitute for a fully executed HAZID workshop, its results are useful for illustrative purposes. For its HAZID analysis, the committee examined hazards pertaining to vessels, weather, geography, waterway navigation, and personnel. The committee identified 17 high-risk hazards, according to the definitions in Table 8-1. The committee also conducted preliminary evaluations on whether high-risk hazards could be lowered to medium or low risk using controls or safeguards. For four of these high-risk hazards, the most typi- cal mitigation actions, if used alone, were inadequate to lower their risk. Multiple safeguards were required to lower these four high-risk hazards to at least medium risk.