Standard Specification for Chocks, Panama, Mooring Cast Steel

ABSTRACT
This specification covers the principal dimensions and materials of chocks installed in ships to comply with the regulations of the Panama Canal. It indicates the workmanship, finish, and appearance of deck mounted chocks, along with the configuration of bulwark mounted chocks. The dimension requirements and classification of chocks are included as well.
SCOPE
1.1 This specification covers the principal dimensions and materials of chocks installed in ships to comply with the regulations of the Panama Canal.  
1.2 Chocks can be used with either wire rope or fiber and synthetic ropes.  
1.3 Chocks are for mounting directly on a deck, seat (foundation) or for mounting in a bulwark.  
1.4 To meet Panama Canal Company regulations the radius of contact surfaces of lines must be 180 mm.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 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-Apr-2023
Drafting Committee
F25.01 - Structures

Relations

Effective Date
01-May-2020
Effective Date
01-Sep-2019
Effective Date
01-May-2017
Effective Date
01-Sep-2016
Effective Date
01-Nov-2013
Effective Date
01-Oct-2010
Effective Date
01-Oct-2008
Effective Date
01-Mar-2005
Effective Date
10-Apr-2003
Effective Date
01-Jan-2000

Overview

ASTM F2935-23: Standard Specification for Chocks, Panama, Mooring Cast Steel defines the essential requirements for cast steel mooring chocks used on ships transiting the Panama Canal. This international standard ensures that chocks meet the principal dimensions, material quality, workmanship, and finish standards necessary to comply with Canal regulations and withstand the demanding shipboard environment. Developed by ASTM Committee F25 on Ships and Marine Technology, the specification supports the safety, durability, and performance of mooring equipment in global marine operations.

Key Topics

  • Scope: Covers chock dimensions, material standards, installation types (deck or bulwark mounted), rope compatibility, and specific Panama Canal requirements.
  • Types and Grades:
    • Types I & III: Deck mounted
    • Types II & IV: Bulwark mounted
    • Grade 1: As-cast surface finish
    • Grade 2: Finished rope contact surface as per ANSI B 46.1 for reduced abrasion.
  • Materials and Manufacture: Requires cast steel conforming to ASTM A27/A27M - Grade 60–30, with smooth, defect-free casting, drainage provisions, and finish criteria.
  • Dimensions and Classification: Chock sizing is based on principal dimensions “L” and “H”; double chocks considered for sizes larger than 360 mm by 260 mm.
  • Workmanship and Finish: Specifies blasting to a gray metal finish, removal of all flashing and irregularities, and detailed surface preparation for rope contact areas.
  • Inspection and Marking: Mandatory quality checks include visual inspections for workmanship and finish, and chocks must be clearly marked with standard reference, type, grade, and order details.

Applications

  • Shipbuilding and Marine Construction: Essential for shipyards and naval architects, this standard ensures chock compliance with international marine safety and operational regulations, especially the stringent Panama Canal requirements.
  • Mooring Operations: Chocks manufactured under ASTM F2935-23 are designed for safe guidance of wire, fiber, and synthetic mooring lines, reducing wear and minimizing the risk of line failure during mooring, towing, and transit operations.
  • Retrofit and Equipment Upgrades: Ship operators upgrading mooring equipment can specify ASTM F2935-23 chocks to ensure compatibility with modern lines and regulatory compliance.
  • Global Maritime Compliance: Adoption of this standard facilitates international trade, as vessels with conforming mooring chocks are recognized by authorities and class societies worldwide for compliance with the Panama Canal Company and World Trade Organization (WTO) principles.

Related Standards

  • ASTM A27/A27M: Standard Specification for Steel Castings, Carbon, for General Application - provides the baseline material requirements for chock castings.
  • ANSI B 46.1: Surface Texture (Roughness, Waviness, Lay) - referenced for grade 2 chock surface finishes.
  • Other Marine Standards: This specification complements broader standards for ship fitting, securing, and safety issued by organizations such as the International Maritime Organization (IMO), American Bureau of Shipping (ABS), and other maritime regulatory bodies.

Keywords: cast steel chocks, Panama chocks, mooring chocks, shipbuilding standards, deck fittings, bulwark chocks, ship mooring equipment, marine castings, ASTM marine standards, Panama Canal compliance.


By following ASTM F2935-23, ship designers, builders, and operators ensure reliable, durable, and internationally compliant mooring solutions, enhancing operational safety and facilitating seamless global passage.

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Frequently Asked Questions

ASTM F2935-23 is a technical specification published by ASTM International. Its full title is "Standard Specification for Chocks, Panama, Mooring Cast Steel". This standard covers: ABSTRACT This specification covers the principal dimensions and materials of chocks installed in ships to comply with the regulations of the Panama Canal. It indicates the workmanship, finish, and appearance of deck mounted chocks, along with the configuration of bulwark mounted chocks. The dimension requirements and classification of chocks are included as well. SCOPE 1.1 This specification covers the principal dimensions and materials of chocks installed in ships to comply with the regulations of the Panama Canal. 1.2 Chocks can be used with either wire rope or fiber and synthetic ropes. 1.3 Chocks are for mounting directly on a deck, seat (foundation) or for mounting in a bulwark. 1.4 To meet Panama Canal Company regulations the radius of contact surfaces of lines must be 180 mm. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 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.

ABSTRACT This specification covers the principal dimensions and materials of chocks installed in ships to comply with the regulations of the Panama Canal. It indicates the workmanship, finish, and appearance of deck mounted chocks, along with the configuration of bulwark mounted chocks. The dimension requirements and classification of chocks are included as well. SCOPE 1.1 This specification covers the principal dimensions and materials of chocks installed in ships to comply with the regulations of the Panama Canal. 1.2 Chocks can be used with either wire rope or fiber and synthetic ropes. 1.3 Chocks are for mounting directly on a deck, seat (foundation) or for mounting in a bulwark. 1.4 To meet Panama Canal Company regulations the radius of contact surfaces of lines must be 180 mm. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 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.

ASTM F2935-23 is classified under the following ICS (International Classification for Standards) categories: 47.020.50 - Deck equipment and installations. The ICS classification helps identify the subject area and facilitates finding related standards.

ASTM F2935-23 has the following relationships with other standards: It is inter standard links to ASTM A27/A27M-20, ASTM A27/A27M-19, ASTM A27/A27M-17, ASTM A27/A27M-13(2016), ASTM A27/A27M-13, ASTM A27/A27M-10, ASTM A27/A27M-08, ASTM A27/A27M-05, ASTM A27/A27M-03, ASTM A27/A27M-95(2000). Understanding these relationships helps ensure you are using the most current and applicable version of the standard.

ASTM F2935-23 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.

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: F2935 − 23 An American National Standard
Standard Specification for
Chocks, Panama, Mooring Cast Steel
This standard is issued under the fixed designation F2935; 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.
1. Scope 3.1.2 closed chock—a metal flared ring-like fitting mounted
on a ship through which mooring lines pass to tow or moor a
1.1 This specification covers the principal dimensions and
ship.
materials of chocks installed in ships to comply with the
3.1.3 mooring ring or pipe—a chock mounted in the bul-
regulations of the Panama Canal.
wark and conforming to Type II or IV.
1.2 Chocks can be used with either wire rope or fiber and
3.1.4 rope contact area—that part of the fitting in contact
synthetic ropes.
with the mooring line in normal mooring operations.
1.3 Chocks are for mounting directly on a deck, seat
(foundation) or for mounting in a bulwark.
4. Classification
1.4 To meet Panama Canal Company regulations the radius
4.1 The size of the chock shall be identified by the nominal
of contact surfaces of lines must be 180 mm.
size “L” and “H” of the opening as shown in Table 1 and Fig.
1, and Table 2 and Fig. 2. Sizes larger than 360 mm by 260 mm
1.5 The values stated in SI units are to be regarded as
may be considered as double chocks.
standard. No other units of measurement are included in this
standard.
4.2 Chocks are furnished in types as follows:
4.2.1 Type I—Deck mounted, as shown in Fig. 1, and
1.6 This international standard was developed in accor-
conforms to all dimensions in Table 1.
dance with internationally recognized principles on standard-
4.2.2 Type II—Bulwark mounted, as shown in Fig. 2, and
ization established in the Decision on Principles for the
conforms to all dimensions in Table 2.
Development of International Standards, Guides and Recom-
4.2.3 Type III—Deck mounted conforming only to dimen-
mendations issued by the World Trade Organization Technical
sions “L”, “H”, and 180 mm radius at entrance, as shown in
Barriers to Trade (TBT) Committee.
Fig. 1 and Table 1.
2. Referenced Documents
4.2.4 Type IV—Bulwark mounted conforming only to di-
mensions “L”, “H”, and 180 mm radius at entrance, as shown
2.1 ASTM Standards:
in Fig. 2 and Table 2.
A27/A27M Specification for Steel Castings, Carbon, for
General Application
4.3 Chocks shall be furnished in either of the following
2.2 ANSI Standards:
grades:
B 46.1 Surface Texture (Roughness, Waviness, Lay)
4.3.1 Grade 1—Surface finish shall be in the as cast
condition.
3. Terminology
4.3.2 Grade 2—Surface finish in way of rope contact shall
3.1 Definitions of Terms Specific to This Standard: be in accordance with 7.2.
3.1.1 bulwark—a structural enclosure along the edge of the
5. Ordering Information
ship to serve as a rail.
5.1 Orders for chocks under this specification shall include
this standard date, and the following:
This specification is under the jurisdiction of ASTM Committee F25 on Ships
5.1.1 Quantity (number) of chocks required,
and Marine Technology and is the direct responsibility of Subcommittee F25.01 on
Structures. 5.1.2 Size (opening, L × H),
Current edition approved May 1, 2023. Published May 2023. Originally
5.1.3 Type and grade,
ε1
approved in 2012. Last previous edition approved in 2018 as F2935 – 12 (2018) .
5.1.4 Primer and coating, if any (see 7.3), and
DOI:10.1520/F2935-23.
2 5.1.5 Marking.
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 6. Materials and Manufacture
the ASTM website.
6.1 Material shall be cast steel in accordance with Specifi-
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. cation A27/A27M, Grade 60–30.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2935 − 23
TABLE 1 Dimension Requirements (see Fig. 1)
(Unit: mm)
Nominal size L l l l l H H H R R R
1 2 3 4 1 2 1 2
310 310 708 688 105 310 260 639
...


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.
´1
Designation: F2935 − 12 (Reapproved 2018) F2935 − 23 An American National Standard
Standard Specification for
Chocks, Panama, Mooring Cast Steel
This standard is issued under the fixed designation F2935; 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.
ε NOTE—Keywords section was editorially added in March 2018.
1. Scope
1.1 This specification covers the principal dimensions and materials of chocks installed in ships to comply with the regulations
of the Panama Canal.
1.2 Chocks can be used with either wire rope or fiber and synthetic ropes.
1.3 Chocks are for mounting directly on a deck, seat (foundation) or for mounting in a bulwark.
1.4 To meet Panama Canal Company regulations the radius of contact surfaces of lines must be 180 mm.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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
2.1 ASTM Standards:
A27/A27M Specification for Steel Castings, Carbon, for General Application
2.2 ANSI Standards:
B 46.1 Surface Texture (Roughness, Waviness, Lay)
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 bulwark—a structural enclosure along the edge of the ship to serve as a rail.
3.1.2 closed chock—a metal flared ring-like fitting mounted on a ship through which mooring lines pass to tow or moor a ship.
This specification is under the jurisdiction of ASTM Committee F25 on Ships and Marine Technology and is the direct responsibility of Subcommittee F25.01 on
Structures.
Current edition approved March 1, 2018May 1, 2023. Published April 2018May 2023. Originally approved in 2012. Last previous edition approved in 20122018 as F2935
ε1
– 12. DOI:10.1520/F2935-12R18E01.12 (2018) . DOI:10.1520/F2935-23.
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 the ASTM website.
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
F2935 − 23
3.1.3 mooring ring or pipe—a chock mounted in the bulwark and conforming to Type II or IV.
3.1.4 rope contact area—that part of the fitting in contact with the mooring line in normal mooring operations.
4. Classification
4.1 The size of the chock shall be identified by the nominal size “L” and “H” of the opening as shown in Table 1 and Fig. 1, and
Table 2 and Fig. 2. Sizes larger than 360 mm by 260 mm may be considered as double chocks.
4.2 Chocks are furnished in types as follows:
4.2.1 Type I—Deck mounted, as shown in Fig. 1, and conforms to all dimensions in Table 1.
4.2.2 Type II—Bulwark mounted, as shown in Fig. 2, and conforms to all dimensions in Table 2.
4.2.3 Type III—Deck mounted conforming only to dimensions “L”, “H”, and 180 mm radius at entrance, as shown in Fig. 1 and
Table 1 and the requirements of Sections 6 – 10.
4.2.4 Type IV—Bulwark mounted conforming only to dimensions “L”, “H”, and 180 mm radius at entrance, as shown in Fig. 2
and Table 2 and the requirements of Sections 6 to 10.
4.3 Chocks shall be furnished in either of the following grades:
4.3.1 Grade 1—Surface finish shall be in the as cast condition.
4.3.2 Grade 2—Surface finish in way of rope contact shall be in accordance with 7.2.
5. Ordering Information
5.1 Orders for chocks under this specification shall include this standard date, and the following:
5.1.1 Quantity (number) of chocks required,
5.1.2 Size (opening, L × H),
5.1.3 Type and grade,
5.1.4 Primer and coating, if any (see 7.3), and
5.1.5 Marking.
6. Materials and Manufacture
6.1 Material shall be cast steel in accordance with Specification A27/A27M, Grade 60–30.
6.2 For Types III and IV the manufacturer shall certify that chock is in compliance with Panama Cana
...

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