OCIMF_Mooring_Equipment_Guidelines_(Second_Edition)

A number of termi.nals have developed information to be used by their operators as guidelines.
Examples of the type of information that would be valuable to the jellY operator for mooring 250
kdwt tankers are shown in Figures 1.8, 1.9 and 1.10. These examples a.re for mooring configurations as
shown and for wind variations, wind only and for flood tide. They have be.en developed for the
following mooring systems: nylon rope, all wire lines and mixed wire and nylon moorings.

l.nclnsion of the mixed mooring case as an example should not be construed to be an endorscmcnr
of this system. Other sites wiJL probably have other criteria on which to base operating limits.

Wit'h 18 nylon ]jTICS Figure [.8 shows lhat sr maximum freeboard (or minimum draft) the loading

arms should be di sconnected at wind speeds of approximately 30 knots peak gust. ru the draft

increases, the permissible wind speed increases to 50 knots peak gust. Loading. arm limits are govcmcd
by vessel motion. For the winch brake capacities shown and for the· wind directions indicated,
mooring line loads become excessive in at least one line at the draft· and wind speeds indicated by
the curved lin~.

For an 18 wire with tails case, Figure 1.9, the loading arm wind limit is constant at 50 knots peak
gust. This Urni! is no longer a function of vessel movement but of tbe allowable stress levels in [he
arm or ships manifold. Allowable wind speeds for mooring are as shown.

Figure L 10 demonstrates a mixed mooring situation wherein 14 wire and tail mooring lines and
4 nylon mooring ropes are used as indicated. In tbis case as Wilh the all wire case the loading arm
wind limits are established by the SlTesses in the arms or ship's manifold. However, a comparison of
the two figures shows there is a marked reduction in the wind speed that can be tolerated by the
mixed mooring wire and rope system.

The foregoin g limitaLions c·an be created for varying combinations of wind and current, vessel draft,
mooring line combinations and configurat ions and various ship winch design brake capacities. The
information thus generated can be used for a number of purposes:

• To decide whether a given ShLP can be moored al a given berth under the expected weather
  conditions.


• To determinc when to discontinue cargo transfer atJd 10 disconnect loading arms.


• To advise the ship when it would be desirable to take on ballast to reduce its freeboard.


• To advise lhe ship when it would be desirable to have tugs available (0 assist in mainta,ining
  the ship's position at the jetty.

1.7.3 Joint Terminal/Ship Meeting and Inspection

As soon as practicable after bcrthing, it is recommended Ihat terminals have their representative

board the vessel to establisll contact with rhe Master or his designate<! represent.ative. At this mccting

the Terminal Representative should provide information relating 10 shore facilities and procedures. In

addition he should in concert with the Ship Representative:

• Complete the Ship/ShQre SafelY C l eck List in line with guidance given in ISGOTT and,
  where appropriate, physically check items before ticking off.


• Obtain details of moorings and winches, including state of maintenance.
  
  
  • Review foreca,~te.o weather and arrange for the Master to be advised of any expected changes.
  
  
  • Assess freeboard limitations.
  
  
  • Assess t,ypc and condition of ship mooring equipment and its ballasting ability.
  
  
  • Determine the condi'lio.lls at which cargo transfer wiU be discontinued and loading arms and
    boses be disconnected and precautions to be taken under high mooring load sit.uations.