1、Designation: F1878 98 (Reapproved 2009)An American National StandardStandard Guide forEscort Vessel Evaluation and Selection1This standard is issued under the fixed designation F1878; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers the evaluation and selection of escortvessels that are to be used to escort ships trans
3、iting confinedwaters. The purpose of the escort vessel is to limit theuncontrolled movement of a ship disabled by loss of propulsionor steering to within the navigational constraints of thewaterway. The various factors addressed in this guide also canbe integrated into a plan for escorting a given s
4、hip in a givenwaterway. The selection of equipment also is addressed in thisguide.1.2 This guide can be used in performance-based analysesto evaluate:1.2.1 the control requirement of a disabled ship,1.2.2 the performance capabilities of escort vessels,1.2.3 the navigational limits and fixed obstacle
5、s of a water-way,1.2.4 the ambient conditions (wind and sea) that will impactthe escort response, and1.2.5 the maneuvering characteristics of combined disabledship/escort vessel(s).1.3 This guide outlines how these various factors can beintegrated to form an escort plan for a specific ship or a spec
6、ificwaterway. It also outlines training programs and the selectionof equipment for escort-related activities.1.4 A flowchart of the overall process for developing andimplementing an escort plan is shown in Fig. 1. The processbegins with the collection of appropriate data, which areanalyzed with resp
7、ect to the performance criteria and inconsultation with individuals having local specialized knowl-edge (such as pilots, waterway authorities, interest groups, orpublic/private organizations, and so forth). This yields escortvessel performance requirements for various transit speeds andconditions; t
8、hese are embodied in the ships escort plan. Whenthe time comes to prepare for the actual transit, the plan isconsulted in conjunction with forecast conditions and desiredtransit speed to select and dispatch the appropriate escort vessel(or combination of vessels). A pre-escort conference is con-duct
9、ed to ensure that all principal persons (ship master, pilot,and escort vessel masters) have a good understanding of howto make a safe transit and interact in the event of an emergency.1.5 This guide addresses various aspects of escorting, in-cluding several performance criteria and methodologies for
10、analyzing the criteria, as well as training, outfitting, and otherescort-related considerations. This guide can be expanded asappropriate to add new criteria, incorporate “lessons learned”as more escorting experience is gained in the industry, or toinclude alternative methodologies for analyzing the
11、 criteria.1.6 This guide addresses physical control of the disabledship with the assistance of the escort vessel(s). Other possiblefunctions, such as firefighting, piloting, or navigational redun-dancy, are outside the scope of this guide. Also, this guide wasdeveloped for application to oceangoing
12、ships in coastalwaterways; it is not suitable for application to barge strings inriverine environments.2. Referenced Documents2.1 Code of Federal Regulations Document:233 CFR Part 168Escort Vessels for Certain Tankers, FinalRule2.2 IMO Resolutions:3IMO Resolution A.601(15)Provision and Display of Ma
13、-neuvering Information on Board ShipsIMO Resolution A.751(18)Interim Standards for ShipManeuverability2.3 Marine Safety Committee Circulars:3MSC Circular 389/Interim Guidelines for Estimating Ma-neuvering Performance in Ship DesignMSC Circular 644/Explanatory Notes to the Interim Stan-dards for Ship
14、 Maneuverability3. Terminology3.1 For purposes of clarity within this guide, the vesselbeing escorted is referred to as the “ship” or “disabled ship.”The vessel accompanying the ship as its escort is referred to asthe “escort vessel.”1This guide is under the jurisdiction of Committee F25 on Ships an
15、d MarineTechnology and is the direct responsibility of Subcommittee F25.06 on MarineEnvironmental Protection.Current edition approved Nov. 1, 2009. Published January 2010. Originallyapproved in 1998. Last previous edition approved in 2004 as F1878 - 98(2004).DOI: 10.1520/F1878-98R09.2Available from
16、the Superintendent of Documents, U.S. Government PrintingOffice, Washington, DC 20402.3Available from the International Maritime Organization, 4Albert Embankment,London, SE1 7SR U.K.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2
17、 The escorting measures addressed in this guide arebased on performance.3.2.1 The term “performance measure” refers to perfor-mance capabilities that must be possessed by the escortvessel(s) in controlling the disabled ship within a particularwaterway. This requires a holistic analysis of the combin
18、edmaneuvering dynamics of the escort vessel(s) and ship withinthe waterway in ambient weather and sea conditions.Performance-based requirements involve extensive preplan-ning and analyses, but offer greater assurance that the escortvessel(s) actually will be effective. The methodologies andprocesses
19、 presented in this guide can be used in determiningthe performance envelope of an escort vessel at different transitspeeds and under a range of weather and sea conditions.3.3 The terms “conventional propulsion” and “omni-directional propulsion” refer to propulsion systems of theescort vessel.3.3.1 C
20、onventional Propulsion SystemThe propulsivethrust is fixed in a fore/aft direction.3.3.2 Omni-Directional Propulsion SystemThe propulsivethrust is steerable in any direction (360) around the hull.Examples are the azimuthing Z-drive screw propeller systemand the vertical axis cycloidal system.3.4 The
21、 terms “direct mode” and “indirect mode” refer totwo towing modes for exerting control forces on a disabledship via towline from the escort vessel.3.4.1 Direct ModeThe towline force is derived directlyfrom the escort vessels propulsion system. In general, thetowline orientation is over the bow or ov
22、er the stern of theescort vessel, and only the propulsive thrust vector parallel tothe towline axis is effective on the disabled ship.3.4.2 Indirect ModeThe towline force is derived from theescort vessels hull drag as it is pulled along behind thedisabled ship (similar to a drag chute). High-perform
23、anceFIG. 1 Flowchart of the Overall Process for Developing and Implementing an Escort PlanF1878 98 (2009)2escort vessels should have sufficient stability so that they canturn approximately sideways to the towline without capsizing(tripping), thereby substantially increasing their hull drag and,conse
24、quently, increasing their towline force. The propulsionsystem of these escort vessels is used indirectly to maintain anover-the-side towline orientation (rather than pull directly onthe towline itself). In the indirect mode, specially designedescort vessels can kite off to one side or the other of t
25、hedisabled ships stern, thereby imposing substantial steeringforces on the ship as well as retarding forces to slow it down.3.5 The terms “parameters” and “constraints” refer to addi-tional conditions that define the escort scenario and response.3.5.1 ParametersAdditional details that are specified
26、aspart of the performance criteria to define more fully theperformance “problem” that must be solved by the escortvessel(s). Parameters are used to customize the performancecriteria to reflect a particular waterway or a specific perfor-mance objective. Examples of parameters include an initialship s
27、peed at moment of failure, or winds, currents, and seastate conditions that must be assumed during the escortresponse.3.5.2 ConstraintsLimitations associated with “solving”the performance problem. Examples of constraints include thestability limits of the escort vessel (which limit how muchtowline h
28、eeling moment the escort vessel can tolerate),strength limits of the ships bollards (which limit how muchtowline force can be applied), or the navigable limits of thewaterway (which limit how much maneuvering room is avail-able).3.6 Definitions:3.6.1 allision, na collision with a fixed object.3.6.2
29、allowable reach, nthe straight line distance forwardfrom the designated ship, parallel to its course direction, to apoint at which a grounding of an allision would occur.3.6.3 allowable transfer, nthe straight line distance fromthe designated ship, perpendicular to its course direction, to apoint at
30、 which a grounding or an allision would occur.3.6.4 assist maneuver, nan escort vessel maneuver inwhich the assisting escort vessel(s) apply maximum steeringforce to a disabled ship to enhance the turn of the rudder. In thismaneuver, the objective is to make the radius of turn of the shipas small as
31、 possible.3.6.5 emergency scenarios, nthe complete description ofthe failure, the navigational situation, and the emergency assistresponse.3.6.6 escort operating area, na subregion of the water-way, harbor, bay, and so forth, that has been identified as theregion in which the escort vessel(s) will s
32、tand by or accompanythe designated ship. The subregion may contain locations thatwould require timely escort vessel assistance should the shipexperience a propulsion or steering failure, or both.3.6.7 escort vessel, na vessel that is assigned to stand byor is dedicated to travel in close proximity t
33、o a designated shipto provide timely assistance should the ship experience apropulsion or steering failure, or both. The escort vessel hasappropriate fendering and towing gear to provide emergencyassist capability relative to the demand of the disabled ship.3.6.8 grounding, nimpact of a ships hull w
34、ith the seabottom.3.6.9 maneuvering coeffcients, na set of numerical coef-ficients the are used in polynomial representations of the forcesacting on a ship in terms of the instantaneous state of the ship.3.6.10 oppose maneuver, nan escort vessel maneuver inwhich the assisting escort vessel(s) apply
35、maximum steeringforce to a disabled ship to turn the ship against its rudder. Inthis maneuver, the objective is to return the ship to its originalheading by opposing the rudder forces.3.6.11 propulsion failure, nthe ship is unable to propel oractively stop itself.3.6.12 response times, nthe sequence
36、 of time delaysfollowing a disabling failure on a transiting ship before theescort vessel(s) can apply corrective forces.3.6.13 rescue tow, na maneuver in which the escort vesselmakes up lines and pulls the disabled ship; undertaken after allforward way has come off the disabled ship.3.6.14 retard m
37、aneuver, nan escort vessel maneuver inwhich the assisting escort vessel(s) apply maximum brakingforce to a disabled ship. In this maneuver, the objective is totake speed off the ship as quickly as possible by pulling astern.The control of a ships heading is not an objective. Alsoreferred to as arres
38、t.3.6.15 rudder failure, nthe ships rudder is locked at someangle or it is swinging uncontrollably.3.6.16 ship track/course, nthe path covered by the shipscenter of gravity during a voyage, a waterway transit, or amaneuver.3.6.17 tactical diameter, nthe distance, perpendicular tothe original course
39、direction, between the ships center ofgravity at the start and at the end of a 180 heading change.3.6.18 zigzag maneuver, na test used to measure theeffectiveness of the rudder to initiate and check coursechanges. The maneuver is described in MSC Circular 644,Section 2.2.3.7 Evaluation and Selection
40、 Variables:3.7.1 transit speeds, nthe speed of the escorted shipmeasured through the water. The transit speed takes intoaccount tidal and wind-driven currents. Transit speed is notover ground (SOG) as measured by Global Positioning System(GPS), Loran, or radar.3.7.2 bollard pull, nthe maximum sustai
41、nable force thatthe escort vessel is able to develop while pulling on a towlineattached to a stationary object. The forward and astern bollardpulls are individually specified.3.7.3 dynamic pull (at a particular speed), nthe maxi-mum sustainable force that the escort vessel is able to developwhile mo
42、ving through the water at a particular speed.3.7.4 transfer, nthe distance perpendicular to the originaltrack that a ships center of gravity travels in a 90 change inheading.3.7.5 advance, nthe distance parallel to the original trackthat a ships center of gravity travels in a 90 change ofheading.3.7
43、.6 performance limits, nlimits of performance mea-sures such that under all circumstances, the use of vessels,equipment, or crew shall not place the life and safety ofF1878 98 (2009)3individuals in jeopardy. No applicable federal or state regula-tions should be exceeded in determining escort vessel
44、perfor-mance capabilities and limits.4. Significance and Use4.1 This guide presents some methodologies to predict theforces required to bring a disabled ship under control within theavailable limits of the waterway, taking into account localinfluences of wind and sea conditions. Presented are method
45、-ologies to determine the control forces that an escort vessel canreasonably be expected to impose on a disabled ship, takinginto account the design of the ship, transit speed, winds,currents, and sea conditions. In some instances, this guidepresents formulae that can be used directly; in other inst
46、ances,in which the interaction of various factors is more complicated,it presents analytic processes that can be used in developingcomputer simulations.4.2 Unlike the more traditional work of berthing assistancein sheltered harbors or pulling a “dead ship” on the end of along towline, the escorting
47、mission assumes that the disabledship will be at transit speed at the time of failure, and that itcould be in exposed waters subject to wind, current, and seaconditions.4.3 The navigational constraints of the channel or waterwaymight restrict the available maneuvering area within which thedisabled s
48、hip must be brought under control before it runsaground or collides with fixed objects in the waterway (seeallision).4.4 The escort mission requires escort vessel(s) that arecapable of responding in timely fashion and that can safelyapply substantial control forces to the disabled ship. Thisentails
49、evaluation of the escort vessels horsepower, steeringand retarding forces at various speeds, maneuverability, stabil-ity, and outfitting (towing gear, fendering, and so forth). Thisguide can be used in developing escort plans for selectingsuitable escort vessel(s) for specific ships in specific water-ways.4.5 The methodologies and processes outlined in this guideare for performance-based analyses of escort scenarios. Thismeans that the acceptability of a vessel (or combination ofvessels) for escorting is based upon the ability to cont
