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Guide for the Optional Class Notation Deep Water Anchoring for Oil Tankers and

Guide for the Optional Class Notation Deep Water Anchoring for Oil Tankers and Bulk Carriers (DWA) GUIDE FOR THE OPTIONAL CLASS NOTATION DEEP WATER ANCHORING FOR OIL TANKERS AND BULK CARRIERS (DWA) MAY 2011 American Bureau of Shipping Incorporated by Act of Legislature of the State of New York 1862 Copyright © 2011 American Bureau of Shipping ABS Plaza 16855 Northchase Drive Houston, TX 77060 USA ii ABS GUIDE FOR THE OPTIONAL CLASS NOTATION DEEP WATER ANCHORING FOR OIL TANKERS & BULK CARRIERS (DWA) . 2011 Foreword Foreword In many instances the increase in the number and size of oil tankers and bulk carriers has out paced the ability of ports to provide sheltered anchorage locations for these vessels. As a consequence, there has been a growing need for owners, operators and the vessel’s crew to anchor these vessels outside a harbor or similar areas of sheltered water. Noting the need to provide these same owners, operators and vessel crews, as well as designers and equipment providers, with a guide to assess the adequacy of anchoring equipment, ABS has, in response to requests from our clients, developed this Guide. This Guide specifies the ABS requirements and criteria for obtaining the optional class notation Deep Water Anchoring (DWA). Included within this Guide are requirements detailing the anchor size, chain length and size, and windlass particulars considered necessary to withstand the environmental conditions that vessels anchoring outside a harbor or similar areas of sheltered water may be exposed to. This Guide becomes effective on the first day of the month of publication. We welcome your feedback. Comments or suggestions can be sent electronically by email to 0rsd@eagle.org. ABS GUIDE FOR THE OPTIONAL CLASS NOTATION DEEP WATER ANCHORING FOR OIL TANKERS & BULK CARRIERS (DWA) . 2011 iii Table of Contents GUIDE FOR THE OPTIONAL CLASS NOTATION DEEP WATER ANCHORING FOR OIL TANKERS AND BULK CARRIERS (DWA) CONTENTS SECTION 1 Anchoring, Mooring and Equipment .................................................... 1 1 General ...............................................................................................1 1.1 Scope and Application.....................................................................1 1.3 Basis of Notation .............................................................................1 3 Deep Water Equipment Number.........................................................1 5 Anchors...............................................................................................3 5.1 Anchor Types ..................................................................................3 7 Anchor Chain ......................................................................................3 7.1 Chain Type......................................................................................3 7.3 Chain Size.......................................................................................3 7.5 Chain Length...................................................................................3 9 Tests ...................................................................................................3 11 Environmental Loads ..........................................................................3 11.1 General............................................................................................3 13 Windlass Support Structure and Cable Stopper.................................4 13.1 General............................................................................................4 13.3 Support Structure ............................................................................4 15 Vessel Support Structure....................................................................7 15.1 General............................................................................................7 15.3 Scantlings........................................................................................7 17 Chain Lockers.....................................................................................7 17.1 General............................................................................................7 17.3 Chain Pipe opening .........................................................................8 19 Hawse Pipes.......................................................................................8 TABLE 1 Equipment for Self-propelled Ocean-going Oil Tankers and Bulk Carriers .............................................................................9 FIGURE 1 Effective Heights of Deck Houses.............................................2 FIGURE 2 Direction of Forces and Weight.................................................6 FIGURE 3 Sign Convention........................................................................6 FIGURE 4A ......................................................................................................8 FIGURE 4B ......................................................................................................8 iv ABS GUIDE FOR THE OPTIONAL CLASS NOTATION DEEP WATER ANCHORING FOR OIL TANKERS & BULK CARRIERS (DWA) . 2011 SECTION 2 Anchor Windlass .................................................................................. 10 1 General .............................................................................................10 1.1 Application.....................................................................................10 1.3 Standards of Compliance ..............................................................10 1.5 Plans and Particulars.....................................................................10 3 Materials and Fabrication..................................................................11 3.1 Materials ........................................................................................11 3.3 Welded Fabrication........................................................................11 5 Design...............................................................................................11 5.1 Mechanical Design ........................................................................11 5.3 Hydraulic Systems.........................................................................12 5.5 Electrical Systems .........................................................................12 5.7 Protection of mechanical components...........................................13 5.9 Coupling ........................................................................................13 7 Shop Inspection and Testing ............................................................13 9 Onboard Tests ..................................................................................13 SECTION 3 Surveys after Construction ................................................................. 14 1 Anchoring System Annual Surveys ..................................................14 3 Anchoring System Special Periodical Surveys.................................14 ABS GUIDE FOR THE OPTIONAL CLASS NOTATION DEEP WATER ANCHORING FOR OIL TANKERS & BULK CARRIERS (DWA) . 2011 1 Section 1: Anchoring, Mooring and Equipment S E C T I O N 1 Anchoring, Mooring and Equipment 1 General 1.1 Scope and Application The objective of this Guide is to provide a standard to assess the adequacy of the anchoring arrangements and equipment for vessels engaging in deep water anchoring. The requirements as specified in this Guide are additional to all other relevant requirements of ABS Rules and Guides associated with the Á symbol. Classed vessels designed, constructed and surveyed in full compliance with the criteria contained within this Guide may be assigned a class notation DWA, Deep Water Anchoring for Ships, in addition to the usual Á symbol, thus À A1 Á DWA. This notation is optional and, at this time, only applicable to oil tankers and bulk carriers having length of 150 meters or more. 1.3 Basis of Notation DWA will signify that the anchor, chain, windlass and support structure of the vessel is in compliance with the requirements contained in this Guide addressing deep water anchoring. The mass per anchor of bower anchors, given in Section 1, Table 1, is for anchors of equal mass. The mass of individual anchors may vary 7% plus or minus from the tabular mass, provided that the combined mass of all anchors is not less than that required for anchors of equal mass. The total length of chain required to be carried onboard, as given in Section 1, Table 1 is to be reasonably divided between the two bower anchors. Chains which are intended to form part of the equipment are not to be used as check chains when the vessel is launched. The inboard ends of the chains of the bower anchors are to be secured by efficient means. Two bower anchors and their chains are to be connected and positioned, ready for use. Where three anchors are given in Section 1, Table 1, the third anchor is intended as a spare bower anchor and is listed for guidance only; it is not required as a condition of classification. Means are to be provided for stopping each chain as it is paid out and the windlass should be capable of heaving in either chain. Suitable arrangements are to be provided for securing the anchors and stowing the chains. The typical requirements in the ABS Rules for Building and Classing Steel Vessels (Steel Vessel Rules) cover temporary mooring of a vessel in a harbor or other sheltered water depth up to 64 m. The requirements herein are intended for temporary mooring of a vessel outside a harbor or similar areas of sheltered water with water depth up to 120 m (394 ft) and generally up to conditions 1.54 m/s (3 knots) current, 14 m/s (27 knots) wind (normally developed at Beaufort 6), and 3 m (10 ft) wave (normally developed at Beaufort 6). 3 Deep Water Equipment Number Anchors and chains are to be in accordance with Section 1, Table 1 and the numbers, mass and sizes of these are to be regulated by the Deep Water Equipment Number (DE) obtained from the following equation: DE = 0.628 ( ) 3 . 2 3 . 2 / 1 1 628 . 0 ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎣ ⎡ − + ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ β α α E where α = cL3 × 10-7 + dL2 × 10-5 + eL × 10-3 + f c = 0.0183 (0.0183, 0.000518) d = 0.209 (0.209, 0.0194) e = –0.621 (–0.621, –0.189) Section 1 Anchoring, Mooring and Equipment 2 ABS GUIDE FOR THE OPTIONAL CLASS NOTATION DEEP WATER ANCHORING FOR OIL TANKERS & BULK CARRIERS (DWA) . 2011 f = 0.0866 β = sL + 8.372 s = 0.156 (0.156, 0.0475) L = length of vessel, in m (ft), as defined in 3-1-1/3.1 of the Steel Vessel Rules E = kΔ2/3 + mBh + nA k = 1.0 (1.0, 1.012) m = 2 (2, 0.186) n = 0.1 (0.1, 0.00929) Δ = molded displacement, as defined in 3-1-1/11.1 of the Steel Vessel Rules B = molded breadth, in m (ft), as defined in 3-1-1/5 of the Steel Vessel Rules h = a + h1 + h2 + h3 + ..., as shown in Section 1, Figure 1. In the calculation of h, sheer, camber, and trim may be neglected a = freeboard, in m (ft), from the summer load waterline amidships h1, h2, h3… = height, in m (ft), on the centerline of each tier of houses having a breadth greater than B/4 A = profile area, in m2 (ft2), of the hull, superstructure and houses above the summer load waterline which are within the Rule length. Superstructures or deck houses having a breadth at any point no greater than 0.25B may be excluded. Screens and bulwarks more than 1.5 m (4.9 ft) in height are to be regarded as parts of houses when calculating h and A FIGURE 1 Effective Heights of Deck Houses A B 3 2 1 a h h h B/8 Section 1 Anchoring, Mooring and Equipment ABS GUIDE FOR THE OPTIONAL CLASS NOTATION DEEP WATER ANCHORING FOR OIL TANKERS & BULK CARRIERS (DWA) . 2011 3 5 Anchors 5.1 Anchor Types High holding power is required in deep water up to 120 m (394 ft) in open seas. Therefore anchors are to be of the stockless High Holding Power (HHP) type with holding power at least twice that of an ordinary stockless anchor of the same mass. The mass of the head of a stockless anchor, including pins and fittings, is not to be less than three-fifths of the total mass of the anchor. 7 Anchor uploads/Ingenierie_Lourd/ abs-anchor-guide.pdf