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From page 33... ... 33 For DUKWs, the greatest risk to passenger safety is flooding from the failure of through-hull penetrations, hull damage, or overtopping waves. Ideally, DUKW vessels would have the capability to remain afloat and upright even when flooded. Read the entire page →
From page 34... ... 34 OPTIONS FOR IMPROVING THE SAFETY OF DUKW TYPE AMPHIBIOUS VESSELS the four DUKW sinking accidents, the principal factors contributing to their loss were as follows: • The Miss Majestic had a driveshaft boot seal that came loose after an incorrect repair. • The Seattle Stretch Duck was missing a large drain plug after a repair. Read the entire page →
From page 35... ... FLOODING AND SURVIVABILITY 35 shaft seals and hull drain plugs that are potential large flooding points if damaged, repaired incorrectly, or inadvertently left open. However, considering the actual casualty events, no DUKW to date has been lost only because of insufficient intact stability. Read the entire page →
From page 36... ... 36 OPTIONS FOR IMPROVING THE SAFETY OF DUKW TYPE AMPHIBIOUS VESSELS The SST contained in 46 CFR 178.330 is in essence a simple proof test performed on the DUKW at the loading (i.e., operating) condition specified in the regulations. Read the entire page →
From page 37... ... FLOODING AND SURVIVABILITY 37 by USCG for DUKWs is 14 degrees or one-half of the upright freeboard submerged, whichever is less. The additional MSC requirements for weather and passenger heeling criteria for open boats were included in an internal memo as early as Novem ber 2007, but not issued as formal USCG guidance until 2018. Read the entire page →
From page 38... ... 38 OPTIONS FOR IMPROVING THE SAFETY OF DUKW TYPE AMPHIBIOUS VESSELS For watertight integrity, which was compromised by the Stretch Duck 7's large splash event in 2015, the regulations in 46 CFR 179.360 cover the engine room compartment vents arrangement. Because the Stretch Duck 7 had been certificated for operation on "protected waters" only, the engine compartment was only required to be able to be made "weathertight," not watertight. Read the entire page →
From page 39... ... FLOODING AND SURVIVABILITY 39 than the maximum number of passengers permitted) loading conditions using the more stringent "open boat" freeboard limits set forth in USCG's internal 2007/2008 Memorandums. Read the entire page →
From page 40... ... 40 OPTIONS FOR IMPROVING THE SAFETY OF DUKW TYPE AMPHIBIOUS VESSELS Flotation Foam The committee notes that fitting flotation foam in the hull is not a viable option to keeping a DUKW afloat and upright in case of a swamping or hull breaching incident. Although installing flotation foam has been used in numerous small recreational and small inspected craft to make them "unsinkable" if swamped or capsized, for DUKWs this approach has been studied by both USCG and by the United Kingdom's Marine Accident Investi gation Branch (MAIB) Read the entire page →
From page 41... ... FLOODING AND SURVIVABILITY 41 Wacker Quacker 1. When fitting the vessel with the required volume of foam to meet the 110 percent reserve buoyancy requirement, it was found that not all of the foam fit under the passenger deck and distributed the rest in the passenger cabin. Read the entire page →
From page 42... ... 42 T A B L E 3 -1 I nfl at ab le B la dd er S iz e an d Fl oa t Si ze : E st im at io ns f or a S tr et ch D uc k L in e D es cr ip ti on V al ue U ni ts Fo rm ul a N ot es 1 St re tc h D uc k 7 L ig ht sh ip 17 ,9 20 lb s Fr om S ta bi lit y L et te r 2 36 P as se ng er s 6, 66 0 lb s 18 5 lb s pe r Pa ss en ge r 3 2 C re w M em be rs 37 0 lb s 18 5 lb s pe r C re w M em be r 4 Fu el a nd M is ce lla ne ou s 46 4 lb s 40 G al lo ns F ue l an d 12 0 #' s M is c 5 To ta l Fu ll L oa d D is pl ac em en t 25 ,4 14 lb s = (1 ) Read the entire page →
From page 43... ... FLOODING AND SURVIVABILITY 43 Advantages • Reserve buoyancy at 100 percent in the event of any flooding incident. • Minimal likelihood that passengers would need to escape the vessel due to flooding, avoiding hazards including canopies and donning life jackets in cramped spaces while under way. Read the entire page →
From page 44... ... 44 OPTIONS FOR IMPROVING THE SAFETY OF DUKW TYPE AMPHIBIOUS VESSELS for waterborne operations. The floats numbered four units on each side and each was fitted with handles on the ends for ease of installation and removal.15 Using molded foam-filled floats would allow the floats to have a more compact, rectangular cross section, as opposed to circular cross section of permanently inflated bladders. Read the entire page →
From page 45... ... FLOODING AND SURVIVABILITY 45 • Added weight may be an issue for over the road operations if maximum vehicle weight limits are exceeded. Combining Methods Because the required external bladders or floats would be fairly large relative to a DUKW's hull size, the committee also explored combining the installation of internal flotation foam with external bladders or floats. Read the entire page →
From page 46... ... 46 T A B L E 3 -2 I nfl at ab le B la dd er a nd F lo at S iz es w it h Pa rt ia l In te rn al F lo ta ti on F oa m : E st im at io ns f or a S tr et ch D uc k L in e D es cr ip ti on V al ue U ni ts Fo rm ul a N ot es 1 St re tc h D uc k 7 L ig ht sh ip 17 ,9 20 lb s Fr om S ta bi lit y L et te r 2 36 P as se ng er s 6, 66 0 lb s 18 5 lb s pe r Pa ss en ge r 3 2 C re w M em be rs 37 0 lb s 18 5 lb s pe r C re w M em be r 4 Fu el a nd M is ce lla ne ou s 46 4 lb s 40 G al lo ns F ue l an d 12 0 #' s M is c 5 To ta l Fu ll L oa d D is pl ac em en t 25 ,4 14 lb s = (1 ) Read the entire page →
From page 47... ... FLOODING AND SURVIVABILITY 47 The Higgins pump, critical for survivability, is a self-priming pump that is chain-driven by the propeller shaft. The Higgins pump is always "on" whenever the DUKW is traveling afloat, but its capacity depends on the propeller speed. Read the entire page →
From page 48... ... 48 OPTIONS FOR IMPROVING THE SAFETY OF DUKW TYPE AMPHIBIOUS VESSELS FIGURE 3-1 Example of a boot seal in a WWII DUKW. Read the entire page →
From page 49... ... FLOODING AND SURVIVABILITY 49 FIGURE 3-2 Miss Majestic rear driveshaft boot after sinking accident. Read the entire page →
From page 50... ... 50 OPTIONS FOR IMPROVING THE SAFETY OF DUKW TYPE AMPHIBIOUS VESSELS 1. Heightened inspections of the original-design boot seals during the required annual and drydock inspections; 2. Read the entire page →
From page 51... ... FLOODING AND SURVIVABILITY 51 4. Institute routine inspections of the emergency bilge pumps to ensure that they are fully operational. Read the entire page →
From page 53... ... FLOODING AND SURVIVABILITY 53 FIGURE 3-4 WWII DUKW with an open hood hatch. Read the entire page →
From page 54... ... 54 OPTIONS FOR IMPROVING THE SAFETY OF DUKW TYPE AMPHIBIOUS VESSELS air vent. The spring closure mechanism was not strong enough to keep the force of the overtopping waves from intermittently opening the air vent.23 In 2015, the same DUKW had experienced flooding of the forward compartment after entering the water harder than normal. Read the entire page →
From page 55... ... FLOODING AND SURVIVABILITY 55 It is critically important to permanently seal or eliminate wherever practical all drain plugs and valves. For any remaining hull drain and maintenance plugs, all maintenance and repair procedures need to be reviewed to ensure that plugs have been correctly reinstalled before the DUKW is allowed back into service. Read the entire page →

From page 33...

... 33 For DUKWs, the greatest risk to passenger safety is flooding from the failure of through-hull penetrations, hull damage, or overtopping waves. Ideally, DUKW vessels would have the capability to remain afloat and upright even when flooded.