BS ISO 13729:2020 Ships and marine technology — Ship’s mooring and towing fittings — Closed chocks

BS ISO 13729:2020 Ships and marine technology — Ship’s mooring and towing fittings — Closed chocks.
1 Scope
This document specifies the types, nominal sizes, dimensions and materials, as well as construction, manufacturing and marking requirements, for closed chocks installed to lead the mooring and towing rope of a ship.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IMO Circular MSC/Circ.1175, Guidance on shipboard towing and mooring equipment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
3.1
safe working load
SWL
safe load limit (maximum permissible load) of the fittings used for mooring and towing
4 Classification
4.1 Type
The closed chock shall be classified by its installation site as belonging to one of the following types:
a) Type A: deck-mounted closed chock;
b) Type B: bulwark-mounted closed chock.
4.2 Nominal sizes
The nominal sizes, L × H × D, of closed chocks are denoted by reference to the width and height of the opening and the depth of the chock, in millimetres. For the closed chocks having the same size, the letter of the alphabet, i.e. A or B, is followed by the nominal size for the different SWL.
The nominal sizes are:
250 × 200 × 214, 300 × 250 × 286, 350 × 250 × 333, 400 × 250 × 381, 450 × 250 × 381, 500 × 250 × 381, 400 × 250 × 428, 450 × 250 × 428, 500 × 250 × 428, 500 × 400 × 428, 500 × 250 × 525A, 500 × 400 × 525A, 500 × 250 × 525B, 500 × 400 × 525B
9.5 The radii of edges and corners not shown in Figure 1 shall be of minimum 25 mm.BS ISO 13729 pdf download.