ASTM F841-19

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
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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.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or the power to drive the thruster.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
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Available from Ameri
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