OCIMF_Mooring_Equipment_Guidelines_(Second_Edition)

Total Maximum Rope Loading in Tonnes

Nominal Size if Load is Applied al 1.2 D above Base,

of Bollard (0) or Lower

in mm

Figure-of-Eight Attached with

Belayed Eye

100 3 6

(^125 4 8)
160 5 10
200 8 16
250 12 24
(^315 20 40)
400 32 64
500 46 92
630 70 140
710 82 164
800 100 200
Noles:

1. Bollard Scantlings per ISO 3913


2. The "figure-ol-eighl" values correspond to ,he "single rope maximum loading"
   in ISO 3913 and are the vatues recommended to be marked on ,he fitting as
   Ihe SWL.
   TABLE 8.1: MAXIMUM PERMISSIBLE ROPE LOADING OF BOLLARDS
   The British Standard refers to the methods of belaying the rope as 'mooriDg' for figure-of-eight
   belaying, and 'towing' for loop belaying. The 'towing' SWL is twice the 'mooring' SWL. Table 8.1
   shows the permissible rope loadings. The reason that the SWL depends on the method of rope

belaying is lhal certain belaying methods tend '0 pull the two posts together and thus induce a

ltigher stress in each barrel than that produced by an eye laid around a single post. With figure-of
-eight belaying, the loading in each post corresponds to the sum of all forces in the successive rope
layers, which can be higher than the maximum rope load. Experienced mariners are aware of this
phenomenon and bave devised methods tbat effectively distribute the external load over 'he two posts
(for instance, by laking one or two turns around the firs! post before starting to belay in figure-
of-eight fashion). Nevertheless, ISO takes a conservative approach by assuming that some mariners
may lack this knowledge. Fig. 8.1 illustrates the two methods of belaying a bollard. Care must be
taken in interpreting tabwared maximum rope loadings for other standards, since design criteria in
t.e1'IIJ1j of belaying methods, and number and height of ropes applied, are not consislent with ISO
deftnitions. See aJso Table 8.1.

8.3 CRUCIFORM BOLLARDS

ISO 3913, Addendum I, covers bollards with a barrel diameter from 70rnm to 400mm. JIS F2804

covers boUards (called cross bilts by JTS) from 150mm to 350mm.

Similarly 10 vertical bollards, (he tabulated 'single rope maximum loading' vaJue quoted in ISO for

double cruciform bollards is the SWL when the rope is applied in figure-of-eight fashion. Since a

single cruciform bollard cannot be overst.ressed if certain belaying methods are used, their SWL is

twice that of a double bollard. No information on height of rope appucation is given in the staJ)dard;

since the scantlings are the same, it is assumed to be the same as for vertical bollards. The design

criteria recommended in Section 4, Table 4.3 should therefore be used.

The BS Standard, MA 12, Part 2 (which is similar to ISO 3913) includes OCIMF recommended

sizes for single cruciJonn bollards for use at tanker manifolds.