1、Designation: F1878 98 (Reapproved 2015) 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 tran
3、siting 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
4、ship 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 obstacl
5、es of awaterway,1.2.4 The ambient conditions (wind and sea) that willimpact the 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 speci
6、ficwaterway. 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 respe
7、ct 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; th
8、ese 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-ducte
9、d 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 fora
10、nalyzing 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 navigationalredundancy, are outside the scope of this guide.Also, this guidewas developed for application to oceangoing ship
12、s in coastalwaterways; it is not suitable for application to barge strings inriverine environments.1.7 The values stated in inch-pound units are to be regardedas standard. No other units of measurement are included in thisstandard.2. Referenced Documents2.1 Code of Federal Regulations Document:233 C
13、FR Part 168 Escort Vessels for Certain Tankers, FinalRule2.2 IMO Resolutions:3IMO Resolution A.601(15) Provision and Display of Ma-neuvering Information on Board ShipsIMO Resolution A.751(18) Interim Standards for Ship Ma-neuverability2.3 Marine Safety Committee Circulars:3MSC Circular 389 Interim G
14、uidelines for Estimating Ma-neuvering Performance in Ship DesignMSC Circular 644 Explanatory Notes to the Interim Stan-dards for Ship Maneuverability1This guide is under the jurisdiction of Committee F25 on Ships and MarineTechnology and is the direct responsibility of Subcommittee F25.07 on General
15、Requirements.Current edition approved May 1, 2015. Published June 2015. Originallyapproved in 1998. Last previous edition approved in 2009 as F1878 98 (2009).DOI: 10.1520/F1878-98R15.2Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, W
16、ashington, DC 20401, http:/www.access.gpo.gov.3Available from the International Maritime Organization (IMO), 4, AlbertEmbankment, London, SE1 7SR, UK, http:/www.imo.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1
17、 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.”3.2 The escorting measures addressed in this guide arebased on performance.3.2.1 The term “performa
18、nce 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 combinedmaneuvering dynamics of the escort vessel(s) and ship withinthe waterway in ambient weather an
19、d 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 presented in this guide can be used in determiningthe performance envelope of an escort vessel
20、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 Conventional Propulsion SystemThe propulsivethrust is fixed in a fore/aft direction.3.3.2 Omni-Di
21、rectional 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 terms “direct mode” and “indirect mode” refer totwo towing modes for exerting control forces on
22、 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 over the stern of theFIG. 1 Flowchart of the Overall Process for Developing and Implementing an Es
23、cort PlanF1878 98 (2015)2escort 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-p
24、erformanceescort vessels should have sufficient stability so that they canturn approximately sideways to the towline without capsizing(tripping), thereby substantially increasing their hull drag and,consequently, increasing their towline force. The propulsionsystem of these escort vessels is used in
25、directly 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 thedisabled ships stern, thereby imposing substantial steeringforces on the ship as well as retar
26、ding 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 aspart of the performance criteria to define more fully theperformance “problem” that must be so
27、lved 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 speed at moment of failure, or winds, currents, and seastate conditions that must be assumed duri
28、ng 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 heeling moment the escort vessel can tolerate),strength limits of the ships bollards (which limit
29、 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 allowable reach, nthe straight line distance forwardfrom the designated ship, parallel to its co
30、urse 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 which a grounding or an allision would occur.3.6.4 assist maneuver, nan escort vessel maneuver
31、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 possible.3.6.5 emergency scenarios, nthe complete description ofthe failure, the navigational s
32、ituation, and the emergency assistresponse.3.6.6 escort operating area, na subregion of thewaterway, harbor, bay, and so forth, that has been identified asthe region in which the escort vessel(s) will stand by oraccompany the designated ship. The subregion may containlocations that would require tim
33、ely escort vessel assistanceshould the ship experience a propulsion or steering failure, orboth.3.6.7 escort vessel, na vessel that is assigned to stand byor is dedicated to travel in close proximity to a designated shipto provide timely assistance should the ship experience apropulsion or steering
34、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 with the seabottom.3.6.9 maneuvering coeffcients, na set of numerical coef-ficients the are used in
35、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 maximum steeringforce to a disabled ship to turn the ship against its rudder. Inthis maneuver, the
36、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 of time delaysfollowing a disabling failure on a transiting ship before theescort vessel(s) can ap
37、ply 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 maneuver, nan escort vessel maneuver inwhich the assisting escort vessel(s) apply maximum brakingfor
38、ce 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 arrest.3.6.15 rudder failure, nthe ships rudder is locked at someangle or it is swinging uncontrollably.
39、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 direction, between the ships center ofgravity at the start and at the end of a 180 heading change.3
40、.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 Variables:3.7.1 transit speeds, nthe speed of the escorted shipmeasured through the water. The tra
41、nsit 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 sustainable force thatthe escort vessel is able to develop while pulling on a towlineattached to a statio
42、nary object. The forward and astern bollardpulls are individually specified.3.7.3 dynamic pull (at a particular speed), nthe maximumsustainable force that the escort vessel is able to develop whilemoving through the water at a particular speed.F1878 98 (2015)33.7.4 transfer, nthe distance perpendicu
43、lar 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.3.7.6 performance limits, nlimits of performance mea-sures such that under all circumsta
44、nces, the use of vessels,equipment, or crew shall not place the life and safety ofindividuals in jeopardy. No applicable federal or state regula-tions should be exceeded in determining escort vessel perfor-mance capabilities and limits.4. Significance and Use4.1 This guide presents some methodologie
45、s 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-ologies to determine the control forces that an escort vessel canreasonably be expected to impose on
46、 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 instances,in which the interaction of various factors is more complicated,it presents analytic processes
47、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 mission assumes that the disabledship will be at transit speed at the time of failure, and that itcou
48、ld 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 ship must be brought under control before it runsaground or collides with fixed objects in the waterwa
49、y (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 evaluation of the escort vessels horsepower, steeringand retarding forces at various speeds, maneuverability,stability, and outfitting (towing gear, fendering, and so forth).This guide 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
