OCIMF_Mooring_Equipment_Guidelines_(Second_Edition)

The minimum restraint capabilitie.s calculated in this section a re for the ballasted case and are as
foUows:

RXA I J65 kN

R.~F 1167 kN

RYF = 2147 kN

RYA = 2321 kN

Tbe longitudinal restraint capabiJilies fore and aft are cl early adequat~. The lateral restraint capabilities
fore and aft are about 5 1170 and 7 CT(iJ deficient respecti~·ely.

Comparison of moor ing line requirements wilh approximaTe formuiae in Section 2.6

Formula (22): S x MBL = 3271 kN

Formula (23): BR x MBL = 12923 kN

Formula (24): S x MBL = 3555 kN

Formula (25): BR x MBL = 12620 kN

Tbis compares wit h tbe available S x M BL of 4 )( 1110 = 4440 kN, and BR )( MBL of 10 )( III 0 =
lIIOOkN.

In all cases the provided spring lines arc more than adequate. The breas t lin es are 140/0 deficient

per formula (23) and 1211,70 deficient per formula (25).

I E.7 SAMPLE OF COMPUTER CALCULATIONS

For the 250 k.dwt tanker carrying l4 wire lines, compur.er runs were made for the 60 knot wind from

0° to 1800 a nd for the currents as given in the d esign mooring condition, ee l ion. BOlh the ballasted

and loaded case.s, with a water depth to draft ratio of 1. J: 1 for the loaded case, and 3.0: I for the

ballast case were analysed, and the maximum loadj ngs in the 42 mm (WRe wire lines are as provided

in the table bc.!ow: Details as to wind area, draft ctc. are found in Appc:ndix D in which the forces

acting on the vessel are calculated, Figure E2 illu~trates ihe mooring l.ine layout used for computational

purposes. Vertical and bor izolltal an gles <Ire as illustrated in Figure 2.10.

Wire Number Load ill TOT/nnes Wire MIII/ber Load in Tonnes

1 63.9* 8 48.1

2 63.5· 9 48.5

3 47.6 10 45.4

4 43.1 II 44.4

(^5) 48.S 12 59.4
6 54.9 13 60 .8
7 54 .4 14 56.2

• Slighlly above 55"1. MBL: bul well within o rd e r of accuracy of calcullltio ns.


• The loads given in the table are the highest loads generated in each line by the varying com-
  binations of wind, current and vessel draught.


• Normal allowable load = 0.55 x 1110 kN = 610 kN


• 1110 kN is minimum breakin g load of th e 42 mm IWRC wire liue which is recommended as the
  minimum sized wire line: for VLCCs.

Tbus, based on our design mooring conditio·ns and assumed ballast condition, 14 wire mooring lines

as specified are required to safely moor the ve~sel.