Sample records for drydocks

  1. 46 CFR 61.20-5 - Drydock examination. (United States)


    ... 46 Shipping 2 2010-10-01 2010-10-01 false Drydock examination. 61.20-5 Section 61.20-5 Shipping... INSPECTIONS Periodic Tests of Machinery and Equipment § 61.20-5 Drydock examination. (a) When any vessel is drydocked, examination shall be made of the propeller, stern bushing, sea connection, and fastenings if...

  2. 32 CFR 700.872 - Ships and craft in drydock. (United States)


    ... 32 National Defense 5 2010-07-01 2010-07-01 false Ships and craft in drydock. 700.872 Section 700... Special Circumstances/ships in Naval Stations and Shipyards § 700.872 Ships and craft in drydock. (a) The... ship or craft, not in commission, is in a naval drydock, the provisions of this article shall apply...

  3. 46 CFR 176.600 - Drydock and internal structural examination intervals. (United States)


    ... including fuel tanks, and may require the vessel to be drydocked or taken out of service to assess the extent of the damage, and to effect permanent repairs. The OCMI may also decrease the drydock examination...

  4. 46 CFR 71.50-3 - Drydock examination, internal structural examination, underwater survey, and alternate hull exam... (United States)


    ..., underwater survey, and alternate hull exam intervals. 71.50-3 Section 71.50-3 Shipping COAST GUARD...-3 Drydock examination, internal structural examination, underwater survey, and alternate hull exam... wooden hulls must undergo two drydock and two internal structural examinations within any five year...

  5. EX1006 Hawaii to San Francisco Transit to Drydock (EX1006, EM302) on Okeanos Explorer in Hawaii, US West Coast (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Okeanos Explorer (EX) will transit from Honolulu, HI to San Francisco for the winter inport and drydock period. During the transit, the EX will perform 24-hour...

  6. Were Viking Dry-dock methods in the Americas used earlier to Build Pyramids, with Outflow Eroding the Sphinx, and were Stonehenge, the Obelisks, and Moas Similarly Erected? (United States)

    McLeod, Edward; McLeod, Roger


    Chisel-quarried recycled granite in MA is datable by runes to 1069 CE; it could corroborate dating by a LIDAR. Associated sites, possibly used by Vikings to dry-dock their ships, could have exploited lock-like controls, possibly a continued technology. Site-leveling at the Giza Pyramids proves water was used. `Locks' and body-immersion worked for building, moving, erecting, or watering, at sites like Stonehenge, The Hanging Gardens at Babylon, the Moas of Easter Island, or The Pyramids, where the eroding water discharge was deliberately flushed over the Sphinx complex. It enhance the electromagnetically excited blue light signals we can detect, especially at sites frequented by Molocket of ME. Information, as at America's Stonehenge, in NH, and constructions at Acton MA, at Giza or at Rumford ME proves that the Pyramids and Sphinx were engineered and built about 4500 BP.

  7. 32 CFR 700.871 - Responsibility for safety of ships and craft at a naval station or shipyard. (United States)


    ... a timely and adequate manner. (c) When a ship or craft not under her own power is being moved by... contractor. (d) When a ship operating under her own power is being drydocked, the commanding officer shall be... ship. (e) When a naval ship is to be drydocked in a private shipyard under a contract being...

  8. 46 CFR 176.675 - Extension of examination intervals. (United States)


    ... 46 Shipping 7 2010-10-01 2010-10-01 false Extension of examination intervals. 176.675 Section 176... 100 GROSS TONS) INSPECTION AND CERTIFICATION Hull and Tailshaft Examinations § 176.675 Extension of examination intervals. The intervals between drydock examinations and internal structural examinations...

  9. 46 CFR 71.50-15 - Description of the Alternative Hull Examination (AHE) Program for certain passenger vessels. (United States)


    ... 46 Shipping 3 2010-10-01 2010-10-01 false Description of the Alternative Hull Examination (AHE... Description of the Alternative Hull Examination (AHE) Program for certain passenger vessels. The Alternative Hull Examination (AHE) Program provides you with an alternative to a drydock examination by allowing...

  10. 46 CFR 91.40-1 - Definitions relating to hull examinations. (United States)


    ... 46 Shipping 4 2010-10-01 2010-10-01 false Definitions relating to hull examinations. 91.40-1... VESSELS INSPECTION AND CERTIFICATION Drydocking § 91.40-1 Definitions relating to hull examinations. As...-hull fittings. (b) Internal structural examination means an examination of the vessel while afloat or...

  11. 46 CFR 71.50-25 - Alternative Hull Examination (AHE) procedure. (United States)


    ... 46 Shipping 3 2010-10-01 2010-10-01 false Alternative Hull Examination (AHE) procedure. 71.50-25... INSPECTION AND CERTIFICATION Drydocking § 71.50-25 Alternative Hull Examination (AHE) procedure. (a) To complete the underwater survey you must— (1) Perform a general examination of the underwater hull plating...

  12. 46 CFR 71.50-19 - The Alternative Hull Examination (AHE) Program application. (United States)


    ... 46 Shipping 3 2010-10-01 2010-10-01 false The Alternative Hull Examination (AHE) Program...) PASSENGER VESSELS INSPECTION AND CERTIFICATION Drydocking § 71.50-19 The Alternative Hull Examination (AHE... apply to the AHE Program. You must submit an application at least 90 days before the requested hull...

  13. 46 CFR 189.40-1 - Definitions relating to hull examinations. (United States)


    ... 46 Shipping 7 2010-10-01 2010-10-01 false Definitions relating to hull examinations. 189.40-1... VESSELS INSPECTION AND CERTIFICATION Drydocking § 189.40-1 Definitions relating to hull examinations. As...-hull fittings. (b) Internal structural examination means an examination of the vessel while afloat or...

  14. 33 CFR 150.815 - How must casualties be reported? (United States)


    ..., gas freeing, dry-docking, or demurrage of the port, vessel, or aircraft. (b) The notice under... (CONTINUED) DEEPWATER PORTS DEEPWATER PORTS: OPERATIONS Reports and Records Reports § 150.815 How must..., operator, or person in charge of a deepwater port must notify the nearest Sector, Marine Safety Unit, or...

  15. 46 CFR 169.231 - Definitions relating to hull examinations. (United States)


    ... 46 Shipping 7 2010-10-01 2010-10-01 false Definitions relating to hull examinations. 169.231... hull examinations. As used in the part— (a) Drydock examination means hauling out a vessel or placing a... and all through-hull fittings, sea chests, sea valves, sea strainers, and valves for the emergency...

  16. 46 CFR 71.50-1 - Definitions relating to hull examinations. (United States)


    ... 46 Shipping 3 2010-10-01 2010-10-01 false Definitions relating to hull examinations. 71.50-1... INSPECTION AND CERTIFICATION Drydocking § 71.50-1 Definitions relating to hull examinations. As used in this part— Adequate hull protection system means a method of protecting the vessel's hull from corrosion. It...

  17. 78 FR 21938 - Final National Pollutant Discharge Elimination System (NPDES) General Permit for Discharges... (United States)


    ... vessel are inspected for permit compliance. If the vessel is placed in dry dock while covered under the permit, a dry dock inspection and report is required to be completed. Additional monitoring requirements... controlled arrangements in port, or at drydock; when feasible and safe, vessels must use ballast water pumps...

  18. 46 CFR 42.09-30 - Additional survey requirements for steel-hull vessels. (United States)


    ... 46 Shipping 2 2010-10-01 2010-10-01 false Additional survey requirements for steel-hull vessels...-30 Additional survey requirements for steel-hull vessels. (a) In addition to the requirements in § 42...) When the vessel is in drydock, the hull plating, etc., shall be examined. (c) The holds, 'tween decks...

  19. 46 CFR 71.50-29 - Hull examination reports. (United States)


    ... 46 Shipping 3 2010-10-01 2010-10-01 false Hull examination reports. 71.50-29 Section 71.50-29... CERTIFICATION Drydocking § 71.50-29 Hull examination reports. (a) If you use only divers for the underwater survey portion of the Alternative Hull Examination (AHE), you must provide the Officer in Charge, Marine...

  20. Drydocking Facilities Characteristics. Design Manual 29.3. (United States)


    BEAM -7’ I07 PRECAST COLUMN j! ’~ FULLY RELIEVED ’ 6 EeDGE OF...SUBMARINE LONGITUDINAL SECTION (VIEW LOOKING WEST) 715𔄀" TO INNER FACE OF CAISSON INOUE SA CRANE TRACKS- PLAN VIEW COPING EL +20.0- 3’ 42’ BEAM ..f... connections west side. Chilled water ..... 6" supply and return mains, 600 gpm at 65 psi, one 6" supply and one 6" return connections west side. Low

  1. Hydrodynamic Energy Saving Enhancements for DDG 51 Class Ships (United States)


    temperature and pressure in the hydraulic pitch control system, expansion and contraction of the pitch control rods, improper pitch calibration procedure ...outdated pitch calibration, etc. Experience during hot pitch calibration procedures conducted by NSWCCD prior to powering trials has indicated that...18% increase in power.10 Sea trials conducted during a long-term evaluation on the USS WHIPPLE (FF 1062), showed that by 800 days out of drydock

  2. Generalized fluid impulse functions for oscillating marine structures (United States)

    Janardhanan, K.; Price, W. G.; Wu, Y.


    A selection of generalized impulse response functions is presented for a variety of rigid and flexible marine structures (i.e. mono-hull, SWATH, floating drydock and twin dock, fixed flexible pile). These functions are determined from calculated and experimental frequency-dependent hydrodynamic data, and the characteristics of these data depend on the type of structure considered. This information is reflected in the shape and duration of the generalized impulse response functions which are pre-requisites for a generalized integro-differential mathematical model describing the dynamic behaviour of the structures to seaway excitation.

  3. Filtration of Runoff From Pressure Washing Vessel Hull in Drydock (United States)


    the most cost-effective treatment system for particular waste streams, especially heavy metals such as Tributyltin ( TBT ), Lead, Zinc, and Copper...solids, sediment, spent grit blast, sea growth, and toxic metals. The chemical and physical parameters of the material were defined to decide the...ported the original hypothesis that little dissolved matter was present in the water. Furthermore, it suggested that TBT , if present, was unlikely to be

  4. Removing vessels from the water for biofouling treatment has the potential to introduce mobile non-indigenous marine species. (United States)

    Coutts, Ashley D M; Valentine, Joseph P; Edgar, Graham J; Davey, Adam; Burgess-Wilson, Bella


    Vessels found contaminated with biofouling non-indigenous marine species are predominantly removed from the water and treated in vessel maintenance facilities (i.e., slipways, travel lifts and dry-docks). Using pre-fouled settlement plates to simulate a vessel's removal from the water for treatment, we demonstrate that a range of mobile organisms (including non-indigenous marine species) may be lost to the marine environment as a consequence of this process. We also determined that different levels of biofouling (primary, secondary and tertiary) and emersion durations (0.5, 5 and 15 min) affected the abundance and composition of mobile taxa lost to the marine environment. Primary biofouling plates lost 3.2% of total animals, secondary plates lost 19.8% and tertiary plates lost 8.2%, while hanging duration had only minor effects. The results suggest that removing vessels contaminated with biofouling non-indigenous marine species from the water for treatment may not be as biosecure as is currently recognised. Copyright 2010 Elsevier Ltd. All rights reserved.

  5. Monitoring the magnitude of marine vessel infestation by non-indigenous ascidians in the Mediterranean. (United States)

    Gewing, Mey-Tal; Shenkar, Noa


    Invasive ascidians (Chordata, Tunicata) are dominant nuisance organisms. The current study investigated the role of marine vessels in their dispersal and introduction. An examination of 45 dry-docked marine vessels, comprising recreational, commercial, and military craft, in five Israeli shipyards along the Mediterranean coast, revealed non-indigenous ascidians (NIA) on every second vessel investigated. Military vessels featured the highest ascidian abundance and richness, potentially related to their maintenance routine. Niche areas on the vessels such as sea chests and the propeller exhibited the highest occurrence of ascidians. Overall, these findings provide strong evidence that marine vessels play an acute role in NIA introduction and dispersal, with military vessels and niche areas on all the vessels being more susceptible to serving as vectors. A discovery of a new introduced species during the surveys suggests that the monitoring of marine vessels can serve as an effective tool for the early detection of NIA. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Distribution of tributyltin in surface sediments from transitional marine-lagoon system of the south-eastern Baltic Sea, Lithuania. (United States)

    Suzdalev, Sergej; Gulbinskas, Saulius; Blažauskas, Nerijus


    The current research paper presents the results of contamination by tributyltin (TBT) compounds in Klaipėda Port, which is situated in a unique marine-lagoon water interaction zone. One hundred fifty-four surface sediment samples have been taken along the whole transition path from lagoon to the sea and analysed in order to quantify the contamination rate in specific environment of high anthropogenic pressure. The detected TBT concentrations ranged from 1 to 5,200 ng Sn g(-1) of dry weight of sediment. The back-trace of horizontal distribution of TBT-contaminated sediments show obvious increase of tributyltin concentrations closer to port areas dealing with ship repair and places of dry-docking facilities. This is a clear indication that those activities are the main source of contamination in the study area. The estimated correlation of TBT concentration in sediments with total organic carbon and the amount of fine fraction (tributyltin is related to potential contamination source areas (ship repairing, dockyards) due to direct input of hazardous substances into the water.

  7. Three decades of TBT contamination in sediments around a large scale shipyard. (United States)

    Kim, Nam Sook; Shim, Won Joon; Yim, Un Hyuk; Ha, Sung Yong; An, Joon Geon; Shin, Kyung Hoon


    Tributyltin (TBT) contamination in sediments was investigated in the vicinity of a large-scale shipyard in the years after the implementation of a total ban on the use of TBT based antifouling paints in Korea. Extremely high level of TBT (36,292ng Sn/g) in surface sediment was found at a station in front of a drydock and near surface runoff outfall of the shipyard. TBT concentration in surface sediments of Gohyeon Bay, where the shipyard is located, showed an apparent decreased TBT concentration gradient from the shipyard towards the outer bay. The vertical distribution of TBT contamination derived from a sediment core analysis demonstrated a significant positive correlation (r(2)=0.88; pTBT concentrations at six stations surveyed before (2003) and seven years after (2010) the total ban showed no significant differences (p>0.05). Despite the ban on the use of TBT, including ocean going vessels, surface sediments are still being heavily contaminated with TBT, and its levels well exceeded the sediment quality guideline or screening values. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Concrete loading column for Maureen field built at Loch Kishorn

    Energy Technology Data Exchange (ETDEWEB)


    The first concrete-built loading column for a North Sea oilfield left the Kyle of Lochalsh under tow on August 18, bound for the Phillips Petroleum Group's Maureen field 163 miles (262 km) eastnortheast of Aberdeen. The 10,000 tonne gravity structure is 430ft (131m) tall and will have cost pounds29 million by the time it is installed offshore. Before starting its 20-day tow behind the tug ''Les Abeilles'', the offshore tankerloading column recently underwent the complex final stages in its construction, involving tow-out from drydock of two concrete sections, their joining by an articulated or hinged joint and then the structure's uprighting in deep water for the fitting of a rotating steel head. The concrete articulated loading column is one of several innovations in the Maureen development programme. The operator, Phillips Petroleum United Kingdom Ltd., and its co-venturers considered that some new approaches were necessary in view of the relatively small size of Maureen's recoverable oil reserves and hence the field's marginal development economics. These innovations included drilling the development wells by semisubmersible drilling rig through a subsea template while the production platform is being built on shore (with a fully completed deck section). Production will commence as soon as the wells are tied back from the subsea template to the platform.

  9. Increased Flooding Risk - Accelerating Threat and Stakeholder Response (United States)

    Atkinson, L. P.; Ezer, T.; De Young, R.; McShane, M. K.; McFarlane, B.


    Coastal cities have been adapting to coastal flooding for centuries. Now, with increased population along the coast combined with increased flooding because of sea level rise (SLR) the vulnerability of coastal cities has increased significantly. In this paper we will discuss the physical threat of accelerating sea level rise and the response of stakeholders. Sallenger et al (2012) stated "... we present evidence of recently accelerated SLR in a unique 1,000-km-long hotspot on the highly populated North American Atlantic coast north of Cape Hatteras and show that it is consistent with a modeled fingerprint of dynamic SLR." In the Northeast Hotspot (NEH) dynamic processes such as Gulf Stream transport can cause local sea level differences (Ezer, 2001). Sweet et al (2009) attributed the anomalously high sea level along the mid-Atlantic in 2009 to dynamic SLR. A recent paper (Ezer and Corlett, 2012 submitted), focused on Chesapeake Bay, confirms Sallenger et al. These accelerations suggest that the higher estimates of SLR in IPCC reports may be better estimates. The combination of local sea level rise and acceleration, even with average coastal storm surge, results in increased vulnerability and economic losses. We will use three examples of stakeholder response to this threat: shipbuilding, cities and insurance. Nuclear aircraft carrier drydock in Newport News, VA - The only drydock where nuclear powered aircraft carriers are built flooded during Hurricane Isabel. A study showed that with a 1 meter sea level rise and no change in storm severity they would have 'Major Flooding' every 4 months rather than every 27 years. Cities infrastructure - In a recent report on sea level rise, the Hampton Roads Planning District Commission (representing nearly 2m people) found that "sea level rise will be a major issue", "there is not yet official state or federal guidance for addressing sea level rise", "…the "…U.S. Army Corps of Engineers has developed guidance…" for their

  10. Present state of 'Mutsu', the general inspection of safety and the repair of shielding

    International Nuclear Information System (INIS)


    The Agency has carried out the works based on the plan for the repair of shielding and the general inspection of safety in the nuclear ship ''Mutsu'' also in 1979. As for the repair of shielding, the permission by the prime minister to alter the nuclear reactor installation was obtained. The contents of the alteration are the repair of primary and secondary shieldings and the additional construction of a tank for storing liquid waste. As for the general inspection of safety, the tests for confirming the functions of main machinery and equipments have been carried out since January, 1979. A set of testing apparatuses was made as the preparation for the flaw detection test of steam generator tubes. As for the general inspection of softwares, the re-evaluation of the design of nuclear reactor plant and the analysis of the accidents in nuclear reactor plant were almost completed. Considering the accident of TMI No. 2 reactor, the inspection of softwares is in progress. The contract for these repair and inspection is not yet made, and the negotiations are under way. The nuclear ship ''Mutsu'' was brought to Sasebo Port in October, 1978, and dry-docked in July, 1979. As the result of inspection, any rust and wear were not found on the bottom plates, rudder and propeller. The survey of environmental radioactivity in Sasebo and Ominato, the budget for the repair and inspection, and the movement of the government are also reported. (Kako, I.)

  11. A preliminary assessment of biofouling and non-indigenous marine species associated with commercial slow-moving vessels arriving in New Zealand. (United States)

    Hopkins, Grant A; Forrest, Barrie M


    Vessel traffic is the primary pathway for non-indigenous marine species introductions to New Zealand, with hull fouling recognised as being an important mechanism. This article describes hull fouling on seven slow-moving commercial vessels sampled over a 1 year period. Sampling involved the collection of images and fouling specimens from different hull locations using a standardised protocol developed to assess vessel biofouling in New Zealand. A total of 29 taxa was identified by expert taxonomists, of which 24% were indigenous to New Zealand and 17% non-indigenous. No first records to New Zealand were reported, however 59% of species were classified as 'unknown' due to insufficient taxonomic resolution. The extent of fouling was low compared to that described for other slow-movers. Fouling cover, biomass and richness were on average 17.1% (SE = 1.8%), 5.2 g (SE = 1.1 g) and 0.8 (SE = 0.07) per photoquadrat (200 x 200 mm), respectively. The fouling extent was lowest on the main hull areas where the antifouling paint was in good condition. In contrast, highest levels of fouling were associated with dry-docking support strips and other niche areas of the hull where the paint condition was poor. Future studies should target vessels from a broader range of bioregions, including vessels that remain idle for extended periods (ie months) between voyages, to increase understanding of the biosecurity risks posed by international commercial slow-movers.

  12. Tres grandes plataformas marinas Mar del Norte

    Directory of Open Access Journals (Sweden)

    Soulas, R.


    Full Text Available This article analyzes the different building stages of three large sea platforms. After studying the structure's main characteristics, preparing scale models and calculating ail the elements, platform construction was carried out in three stages: — Dry-dock construction of the hull base. — Installation in the water and finishing the structure. — Immersion and bridge installation. Finally, the necessary operations to move the platform to its definite location were carried out. The structures are formed by a parallelepiped hull of reinforced concrete, divided into compartments by means of vertical orthogonals panels on top of which 2 or 4 piles are placed to support the bridge.

    En este artículo se analizan las diversas etapas en la realización de tres grandes plataformas marinas. Después de un estudio de las características principales de la estructura, ensayos en modelo reducido y cálculo de todos los elementos, se procede a la construcción de las plataformas en tres fases: — Construcción en seco de la base del casco. — Colocación en el agua y acabado de la estructura. — Inmersión y colocación del puente. Por último, se realizan las operaciones necesarias para llevar la plataforma a su ubicación definitiva. Las estructuras están formadas por un casco paralelepipédico de hormigón armado, dividido en compartimientos mediante tabiques verticales ortogonales y sobre el que se han colocado 2 ó 4 pilas que soportan el puente.

  13. Diversitas Kultural dan Pengelolaan Konflik Dalam Sebuah Organisasi Bisnis Multinasional

    Directory of Open Access Journals (Sweden)

    MC Ninik Sri Rejeki


    Full Text Available The theoritical analysis is inspired by the labor riot occurred in Drydocks World Graha Shipyards Company in Batam April 22, 2010. This case has reminded us to consider the importance of diversity management for business organization. Such organization has a reality of cultural diversity in its employees and usually it is a multinational company. Such company has grown and expanded in accordance with the development of the global economic order. The reality of cultural diversity actually can be positive forces to sustain the dynamics of the organization, but if not properly managed it can make the negative impact of disadvantageous communication climate. It can enrich the communication climate practices of racism and discrimination. The goal of diversity management is to maximize the positive forces of cultural diversity and to minimize its negative impacts. Management of diversity is itself a way of managing an organization that requires the multicultural paradigm. Inter-group conflict management is an integral part of the management of diversity. At the group level, it is necessary to understand the factors of inter-group conflict. When the conflict as the adverse effect of cultural diversity occurs, that is needed is a constructive management. Parties who have a burden of adaptation should be accommodative to other parties. Accommodation is conducted in the way of viewing the conflict, attitudes, and management style. It is also needs to be developed a communication climate that may reduce the prejudices which is the source of the practices of racism and discrimination.

  14. Library holdings for EX1006: Hawaii to San Francisco Transit to Drydock on NOAA Ship Okeanos Explorer between October 10, 2010 and October 18, 2010 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Library Catalog may include: Data Management Plans, Cruise Plans, Cruise Summary Reports, Scientific "Quick Look Reports", Video Annotation Logs, Image Collections,...

  15. Ship operation and failure mode analysis using a maneuver simulator (United States)

    Cabrerizo-Morales, Miguel Angel; Molina, Rafael; de los Santos, Francisco; Camarero, Alberto


    In a ship or floating structure operation the agents that contribute to the systems behaviour are not only those derived from fluid-structure interaction, but also the ones linked to mooring-control line set-up evolution and human interaction. Therefore, the analysis of such systems is affected by boundary conditions that change during a complete operation. Frequently, monitoring techniques in laboratory (model) and field (prototype) are based in different instrumental techniques adding difficulty to data comparison and, in some cases, inducing precision and repeatability errors. For this reason, the main aim of this study is to develop the methods and tools to achieve a deep knowledge of those floating systems and obtain capabilities to optimize their operationally thresholds. This abstract presents a methodology and an instrumental system applicable both in field and laboratory: SRECMOCOS Project (Small scale REal-time Caisson MOnitoring and COntrol System). SRECMOCOS compiles three modules. For the monitoring and control of the structure it has been developed a synchronized open and modular microcontroller-based electronic system that comprises sensors, to monitor agents and reactions, and actuators to perform pertinent actions after processing the sensors' data. A secondary objective has been to design and implement a global scaled simulator (1:22), at the 3D basin of The Harbour Research Lab at Technical University of Madrid, in which climatic agents and those derived from the rig/maneuvering setup and the structural design were included. The particular case of Campamento's drydock, in Algeciras Bay (Spain), has been used to apply and validate the methodology. SRECMOCOS Project conjugates control, monitoring and wireless communication systems in a real time basis, offering the possibility to register and simulate all the parameters involved in port operations. This approach offers a step forward into a monitoring strategy to be included in monitoring

  16. Reliability-based assessment of deteriorating ship-shaped offshore structures

    Energy Technology Data Exchange (ETDEWEB)

    Ayala-Uraga, Efren


    Floating production, storage and off loading ships, referred to as FPSOs, are hybrid structures in the sense that these vessels are ships being operated as offshore facilities. Production ships or FPSOs constitute an efficient solution for remote oil field locations due to their storage capacity of crude oil. Production ships are either tanker conversions or purpose-built vessels. Most of the applications of production ships are converted ocean-going oil tankers, of different ages, to operate in relatively benign environmental areas. Keeping in mind that merchant ships are usually dry-docked every fifth year for inspection, maintenance and repair (IMR) tasks, they are designed according to a more relaxed safety criteria compared to those normally applied for permanent offshore structures, in which the required IMR activities need to be carried out in-situ as they cannot be easily dry-docked. Moreover, ocean on-going ships may in principle avoid heavy weather conditions, whereas FPSOs are moored to a fixed location and could be exposed to harsher extreme conditions. Additionally, FPSOs are exposed to continuously varying still-water load effects, due to the permanent loading-off loading operations. These fundamental differences are even more important to recognize as most of the existing FPSOs around the globe are built based on converted hulls of oil tankers that have already operated during some years. This issue is particularly relevant for vessels whose service life need to be extended, as the deteriorating agents such as fatigue cracking and corrosion become more important. During the initial design of ship structures, the effects of fatigue and corrosion are accounted for separately. However, as the structure ages, the interaction between these two degrading agents increases, and thus such an interaction needs to be accounted for. Moreover, as the number of cracks in a hull structure increases with time, the likelihood of fracture occurrence in main structural

  17. Numerical simulation of groundwater flow at Puget Sound Naval Shipyard, Naval Base Kitsap, Bremerton, Washington (United States)

    Jones, Joseph L.; Johnson, Kenneth H.; Frans, Lonna M.


    Information about groundwater-flow paths and locations where groundwater discharges at and near Puget Sound Naval Shipyard is necessary for understanding the potential migration of subsurface contaminants by groundwater at the shipyard. The design of some remediation alternatives would be aided by knowledge of whether groundwater flowing at specific locations beneath the shipyard will eventually discharge directly to Sinclair Inlet of Puget Sound, or if it will discharge to the drainage system of one of the six dry docks located in the shipyard. A 1997 numerical (finite difference) groundwater-flow model of the shipyard and surrounding area was constructed to help evaluate the potential for groundwater discharge to Puget Sound. That steady-state, multilayer numerical model with homogeneous hydraulic characteristics indicated that groundwater flowing beneath nearly all of the shipyard discharges to the dry-dock drainage systems, and only shallow groundwater flowing beneath the western end of the shipyard discharges directly to Sinclair Inlet.Updated information from a 2016 regional groundwater-flow model constructed for the greater Kitsap Peninsula was used to update the 1997 groundwater model of the Puget Sound Naval Shipyard. That information included a new interpretation of the hydrogeologic units underlying the area, as well as improved recharge estimates. Other updates to the 1997 model included finer discretization of the finite-difference model grid into more layers, rows, and columns, all with reduced dimensions. This updated Puget Sound Naval Shipyard model was calibrated to 2001–2005 measured water levels, and hydraulic characteristics of the model layers representing different hydrogeologic units were estimated with the aid of state-of-the-art parameter optimization techniques.The flow directions and discharge locations predicted by this updated model generally match the 1997 model despite refinements and other changes. In the updated model, most