ASTM_F_841_-_84_2011.pdf

Designation:F84184(Reapproved 2011)An American National StandardStandard Specification forThrusters,Tunnel,Permanently Installed in Marine Vessels1This standard is issued under the fixed designation F841;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This specification supplies general characteristics andinterface details of propeller type,fixed-tunnel thruster unitspermanently installed in marine vessels or structures.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.NOTE1This specification supplies only general design,interface,andpurchase information and does not include requirements for use,thrustercontrols,or associated equipment.The purchaser of the thruster equipmentspecified herein is cautioned that he must properly correlate the operatingrequirements with the thruster specified.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2A296 Specification for Corrosion-Resistant Iron-Chromiumand Iron-Chromium Nickel and Nickel-B Alloy Castings;Replaced by A 743,A 744(Withdrawn 1980)3F25 Test Method for Sizing and Counting Airborne Particu-late Contamination in Cleanrooms and Other Dust-Controlled Areas2.2 American Bureau of Shipping:4ABS Rules for Building and Classing Steel Vessels2.3 ISO Document:5ISO Recommendation ISO/DIS 484 11(Draft)3.Definitions of Terms Specific to This Standard3.1 thrustera device constructed such as to provide a forceor thrust of controlled variable magnitude and direction to amarine vessel or structure,usually,but not limited to,apropeller mounted within a tunnel located below water level.3.2 fixed pitch(FP)a propeller in which the blades are partof,or are rigidly attached to,the hub such that the propellerpitch is constant for a given radius.3.3 controllable pitch(CP)a propeller in which the bladesare attached to a mechanism within the hub by means of boltsor fasteners,so that controlled movement of the mechanismcauses the blades to change pitch in unison.3.4 tunnela part of thruster assembly of circular crosssection which houses structure supporting a propeller and drivemechanism.3.5 peak powerhighest horsepower developed by theprime mover,or as limited by the thruster manufacturer.3.6 continuous dutyoperation of the thruster continuouslyat any power range,up to manufacturers rating,for extendedperiods,but not to overlap into recommended maintenanceintervals.3.7 intermittent dutyoperation of the thruster at peakpower or RPM levels,or both,for periods not exceeding 1 hfollowed by periods of 1 h at the continuous rating or less,withtotal running time not exceeding 8 h in 24 h.3.8 landing barspermanent attachments,usually in theform of plates welded to the tunnel during manufacture,intended to provide joining facilities for deck plates orbulkheads,or both,at installation.Landing bars are neither1This specification is under the jurisdiction of ASTM Committee F25 on Shipsand Marine Technology and is the direct responsibility of Subcommittee F25.11 onMachinery and Piping Systems.Current edition approved April 1,2011.Published April 2011.Originallyapproved in 1984.Last previous edition approved in 2006 as F841 84(2006).DOI:10.1520/F0841-84R11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American Bureau of Shipping(ABS),ABS Plaza,16855Northchase Dr.,Houston,TX 77060,http:/www.eagle.org.5Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 intended to be part of the support structure for the thruster,norprovide support or transmit forces from the vessel structure tothe thruster.3.9 prime moverthe motor(s)or engine(s)providing thepower to drive the thruster.3.10 grid barsbars installed at the tunnel entrances in theform of a mesh to prevent large objects from passing throught