ASTM F841-84(2011)
(Specification)Standard Specification for Thrusters, Tunnel, Permanently Installed in Marine Vessels
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 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 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 and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:F841 −84 (Reapproved 2011) An American National Standard
Standard Specification for
Thrusters, Tunnel, Permanently Installed in Marine Vessels
ThisstandardisissuedunderthefixeddesignationF841;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.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.
1. Scope 2.2 American Bureau of Shipping:
ABS Rules for Building and Classing Steel Vessels
1.1 This specification supplies general characteristics and
interface details of propeller type, fixed-tunnel thruster units 2.3 ISO Document:
permanently installed in marine vessels or structures. ISO Recommendation ISO/DIS484⁄11(Draft)
1.2 The values stated in either SI units or inch-pound units
3. Definitions of Terms Specific to This Standard
are to be regarded separately as standard. The values stated in
each system may not be exact equivalents; therefore, each
3.1 thruster—adeviceconstructedsuchastoprovideaforce
system shall be used independently of the other. Combining
or thrust of controlled variable magnitude and direction to a
values from the two systems may result in non-conformance marine vessel or structure, usually, but not limited to, a
with the standard.
propeller mounted within a tunnel located below water level.
NOTE 1—This specification supplies only general design, interface, and 3.2 fixed pitch—(FP)apropellerinwhichthebladesarepart
purchase information and does not include requirements for use, thruster
of, or are rigidly attached to, the hub such that the propeller
controls,orassociatedequipment.Thepurchaserofthethrusterequipment
pitch is constant for a given radius.
specified herein is cautioned that he must properly correlate the operating
requirements with the thruster specified. 3.3 controllable pitch—(CP)apropellerinwhichtheblades
are attached to a mechanism within the hub by means of bolts
1.3 This standard does not purport to address all of the
or fasteners, so that controlled movement of the mechanism
safety concerns, if any, associated with its use. It is the
causes the blades to change pitch in unison.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
3.4 tunnel—a part of thruster assembly of circular cross
bility of regulatory limitations prior to use.
sectionwhichhousesstructuresupportingapropelleranddrive
mechanism.
2. Referenced Documents
3.5 peak power—highest horsepower developed by the
2.1 ASTM Standards:
prime mover, or as limited by the thruster manufacturer.
A296Specification for Corrosion-Resistant Iron-Chromium
3.6 continuous duty—operation of the thruster continuously
and Iron-Chromium Nickel and Nickel-BAlloy Castings;
at any power range, up to manufacturer’s rating, for extended
Replaced by A743, A744 (Withdrawn 1980)
periods, but not to overlap into recommended maintenance
F25Test Method for Sizing and CountingAirborne Particu-
intervals.
late Contamination in Cleanrooms and Other Dust-
Controlled Areas
3.7 intermittent duty—operation of the thruster at peak
power or RPM levels, or both, for periods not exceeding 1 h
followedbyperiodsof1hatthecontinuousratingorless,with
total running time not exceeding8hin24h.
3.8 landing bars—permanent attachments, usually in the
This specification is under the jurisdiction ofASTM Committee F25 on Ships
and Marine Technology and is the direct responsibility of Subcommittee F25.11 on
form of plates welded to the tunnel during manufacture,
Machinery and Piping Systems.
intended to provide joining facilities for deck plates or
Current edition approved April 1, 2011. Published April 2011. Originally
bulkheads, or both, at installation. Landing bars are neither
approved in 1984. Last previous edition approved in 2006 as F841–84 (2006).
DOI: 10.1520/F0841-84R11.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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 Available from American Bureau of Shipping (ABS), ABS Plaza, 16855
the ASTM website. Northchase Dr., Houston, TX 77060, http://www.eagle.org.
3 5
The last approved version of this historical standard is referenced on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
www.astm.org. 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
F841−84 (2011)
intended to be part of the support structure for the thruster, nor 5.2.2 Applicable classification society.
provide support or transmit forces from the vessel structure to 5.2.3 Length at waterline.
the thruster. 5.2.4 Width at waterline.
5.2.5 Draft, loaded forward after or draft, ballast forward
3.9 prime mover—the motor(s) or engine(s) providing the
after.
power to drive the thruster.
5.2.6 Dimension of keel to thruster centerline.
3.10 grid bars—bars installed at the tunnel entrances in the
5.2.7 Dimension of bow at waterline to thruster centerline.
form of a mesh to prevent large objects from passing through
5.2.8 Beam at the thruster centerline.
thethrustertunnel.Theareaoccupiedbythegridbarsshallnot
5.2.9 Vessel displacement.
exceed 6% of the tunnel cross-sectional area.
5.2.10 Vessel service and operating environment.
5.2.11 Whether grid bars are to be installed.
4. Classification
6. Materials and Manufacture
4.1 Thrusters manufactured in accordance with this specifi-
cation shall be identified as follows:
6.1 General Requirements—The tunnel shall be made of
4.1.1 Type I—Fixed pitch.
tested steel ofABS quality or equal, fabricated, cast or forged,
4.1.2 Type II—Controllable pitch.
or a combination thereof. All structural welding shall be in
accordance with the applicable regulatory agency or the
4.2 Each type of thruster may be manufactured to the
thruster manufacturer’s recommendations or both. All welds
following grade:
exposed to (sea) water shall be overlayed with weld metal
4.2.1 Grade 1—Intermittent duty for docking and naviga-
containing 2½% nickel, minimum. The minimum tunnel
tion.
material thickness shall meet applicable classification society
4.2.2 Grade 2—Continuous duty for stationkeeping or dy-
requirements. A replaceable insert may be provided in the
namic positioning.
tunnel in way of the propeller tips to prevent erosion of the
5. Ordering Information tunnel wall (Fig. 3). The minimum width of the insert shallbe
10% of the propeller diameter. If an insert is not used, the
5.1 Requestsforquotationandpurchaseordersshallspecify
tunnel thickness in way of the blades, and for a minimum
the following (in absence of specific requirements in ordering
length of 10% of the tunnel diameter, shall be increased by at
data, the unit will be provided only as specified herein):
least 10% of the required thickness. Reenforcement rings/
5.1.1 Description of thruster.
stiffeners may be applied at each end of the tunnel by the
5.1.2 ASTM designation and date of issue.
manufacturer. The rings may or may not become part of the
5.1.3 Type.
joint detail to the tunnel extension.
5.1.4 Grade.
5.1.5 Input Shaft Angle—Refer to Fig. 1. 6.2 Propeller blades and hub may be one of the following
5.1.6 Tunnel Extensions—Refer to Fig. 2. materials or other material approved by the applicable classi-
fication society and shall be specified in the ordering data.
5.1.7 Landing bars or other weldments to the thruster to be
shown in a sketch or drawing provided by the purchaser. 6.2.1 Ni-Al Bronze ABS Type 4.
6.2.2 Stainless Steel Specification A296–77 GR CF-3 or
5.1.8 Type of prime mover.
5.1.9 Input HP and RPM to thruster. CF-8C.
6.2.3 Manganese Bronze ABS Type 2.
5.1.10 Material Options for Hub and Blades:
5.1.10.1 Ni-Al Bronze ABS Type 4.
6.3 All fasteners exposed to (sea) water shall be of monel,
5.1.10.2 StainlesssteelSpecificationA296–72GRCF-3or
stainless-steel, or bronze alloy, unless otherwise specified in
CF-8C or other ABS approved material.
the ordering data.
5.1.10.3 Manganese bronze ABS Type 2.
6.4 All materials shall be free of imperfections and defects
5.1.11 Blade hatch.
that adversely affect serviceability.
5.1.12 Instruction books (unless otherwise specified, six
copies in English). 6.5 All steel surfaces exposed to (sea) water shall be
5.1.13 Tunnel insert (erosion liner).
cleaned, painted, or coated in accordance with manufacturer’s
5.1.14 Paintingorcoating,external(watercontactsurfaces). commercial practice or as otherwise specified in ordering data.
5.1.15 Painting or coating, internal (inside hull).
6.6 All steel surfaces that will be within the hull of the
5.1.16 Blade Balancing—Manufacturer standard practice or
vessel shall be
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