ASTM F841-19

Standard Specification for Thrusters, Tunnel, Permanently Installed in Marine Vessels

ABSTRACT
This specification supplies the general characteristics and requirements, and interface details of propeller-type, fixed-tunnel thruster units that are permanently installed in marine vessels or structures. Thrusters manufactured in accordance with this specification shall be identified by the following types and grades: Type I—fixed pitch; and Type II—controllable pitch; Grade 1—intermittent duty for docking and navigation; and Grade 2—continuous duty for stationkeeping or dynamic positioning. The thrusters shall meet the design, manufacturing, dimensional, and workmanship requirements specified herein.
SCOPE
1.1 This specification supplies general characteristics and interface details of propeller type, fixed-tunnel thruster units permanently installed in marine vessels or structures.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
Note 1: This specification supplies only general design, interface, and purchase information and does not include requirements for use, thruster controls, or associated equipment. The purchaser of the thruster equipment specified herein is cautioned that he must properly correlate the operating requirements with the thruster specified.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Nov-2019
• ICS: 47.020.70 - Navigation and control equipment
• Technical Committee: F25 - Ships and Marine Technology
• Drafting Committee: F25.11 - Machinery and Piping Systems

Relations

• Refers: ASTM A743/A743M-17 - Standard Specification for Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General Application
• Effective Date: 01-Nov-2017

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F841 −19 An American National Standard
Standard Specification for
1
Thrusters, Tunnel, Permanently Installed in Marine Vessels
ThisstandardisissuedunderthefixeddesignationF841;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) 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.
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1. Scope 2.3 ISO Document:
ISO 484-2 Shipbuilding — Ship Screw Propellers — Manu-
1.1 This specification supplies general characteristics and
facturing Tolerances — Part 2: Propellers of Diameter
interface details of propeller type, fixed-tunnel thruster units
Between 0,80 and 2,50 m Inclusive
permanently installed in marine vessels or structures.
1.2 The values stated in inch-pound units are to be regarded
3. Terminology
as standard. The values given in parentheses are mathematical
3.1 Definitions of Terms Specific to This Standard:
conversions to SI units that are provided for information only
3.1.1 continuous duty, n—operation of the thruster continu-
and are not considered standard.
ously at any power range, up to manufacturer’s rating, for
NOTE 1—This specification supplies only general design, interface, and
extended periods, but not to overlap into recommended main-
purchase information and does not include requirements for use, thruster
tenance intervals.
controls,orassociatedequipment.Thepurchaserofthethrusterequipment
specified herein is cautioned that he must properly correlate the operating 3.1.2 controllable pitch (CP), n—a propeller in which the
requirements with the thruster specified.
blades are attached to a mechanism within the hub by means of
1.3 This standard does not purport to address all of the bolts or fasteners, so that controlled movement of the mecha-
nism causes the blades to change pitch in unison.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.1.3 fixed pitch (FP), n—apropellerinwhichthebladesare
priate safety, health, and environmental practices and deter-
part of, or are rigidly attached to, the hub such that the
mine the applicability of regulatory limitations prior to use.
propeller pitch is constant for a given radius.
1.4 This international standard was developed in accor-
3.1.4 grid bars, n—bars installed at the tunnel entrances in
dance with internationally recognized principles on standard-
the form of a mesh to prevent large objects from passing
ization established in the Decision on Principles for the
through the thruster tunnel. The area occupied by the grid bars
Development of International Standards, Guides and Recom-
shall not exceed 6 % of the tunnel cross-sectional area.
mendations issued by the World Trade Organization Technical
3.1.5 intermittent duty, n—operation of the thruster at peak
Barriers to Trade (TBT) Committee.
power or RPM levels, or both, for periods not exceeding 1 h
2. Referenced Documents
followed by periods of1hatthe continuous rating or less, with
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total running time not exceeding8hin24h.
2.1 ASTM Standards:
A743/A743M Specification for Castings, Iron-Chromium,
3.1.6 landing bars, n—permanent attachments, usually in
Iron-Chromium-Nickel, Corrosion Resistant, for General
the form of plates welded to the tunnel during manufacture,
Application
intended to provide joining facilities for deck plates or
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2.2 American Bureau of Shipping:
bulkheads, or both, at installation. Landing bars are neither
ABS Rules for Building and Classing Steel Vessels
intended to be part of the support structure for the thruster, nor
provide support or transmit forces from the vessel structure to
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This specification is under the jurisdiction of ASTM Committee F25 on Ships
the thruster.
and Marine Technology and is the direct responsibility of Subcommittee F25.11 on
3.1.7 peak power, n—highest horsepower developed by the
Machinery and Piping Systems.
Current edition approved Dec. 1, 2019. Published January 2020. Originally
prime mover, or as limited by the thruster manufacturer.
approved in 1984. Last previous edition approved in 2011 as F841 – 84 (2011).
3.1.8 prime mover, n—the motor(s) or engine(s) providing
DOI: 10.1520/F0841-19.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or the power to drive the thruster.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
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3
Available from Ameri
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This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F841 − 84 (Reapproved 2011) F841 − 19 An American National Standard
Standard Specification for
1
Thrusters, Tunnel, Permanently Installed in Marine Vessels
This standard is issued under the fixed designation F841; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) 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. Scope
1.1 This specification supplies general characteristics and interface details of propeller type, fixed-tunnel thruster units
permanently installed in marine vessels or structures.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the given in parentheses are mathematical conversions to SI units that are
provided for information only and are not considered standard.
NOTE 1—This specification supplies only general design, interface, and purchase information and does not include requirements for use, thruster
controls, or associated equipment. The purchaser of the thruster equipment specified herein is cautioned that he must properly correlate the operating
requirements with the thruster specified.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
A296A743/A743M Specification for Corrosion-Resistant Iron-Chromium and Iron-Chromium Nickel and Nickel-B Alloy
Castings; Replaced by A 743, A 744Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General
Application (Withdrawn 1980)
F25 Test Method for Sizing and Counting Airborne Particulate Contamination in Cleanrooms and Other Dust-Controlled Areas
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2.2 American Bureau of Shipping:
ABS Rules for Building and Classing Steel Vessels
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2.3 ISO Document:
ISO Recommendation ISO/DIS 484484-2⁄11 (Draft) Shipbuilding — Ship Screw Propellers — Manufacturing Tolerances —
Part 2: Propellers of Diameter Between 0,80 and 2,50 m Inclusive
3. Definitions of Terms Specific to This Standard
3.1 thruster—a device constructed such as to provide a force or thrust of controlled variable magnitude and direction to a marine
vessel or structure, usually, but not limited to, a propeller mounted within a tunnel located below water level.
3.2 fixed pitch—(FP) a propeller in which the blades are part of, or are rigidly attached to, the hub such that the propeller pitch
is constant for a given radius.
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This specification is under the jurisdiction of ASTM Committee F25 on Ships and Marine Technology and is the direct responsibility of Subcommittee F25.11 on
Machinery and Piping Systems.
Current edition approved April 1, 2011Dec. 1, 2019. Published April 2011January 2020. Originally approved in 1984. Last previous edition approved in 20062011 as
F841 – 84 (2011). (2006). DOI: 10.1520/F0841-84R11.10.1520/F0841-19.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
3
Available from American Bureau of Shipping (ABS), ABS Plaza, 16855 Northchase Dr., Houston, TX 77060,1701 City Plaza Drive, Spring TX 77389,
http://www.eagle.org.
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Available 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 States
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F841 − 19
3.3 controllable pitch—(CP)
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