All port users will be aware of the advantages that have available to certain shipping trades within the port since 1994 through the use of Dynamic Under-Keel Clearance (DUKC). To date the benefits have been available to specific container trades, large tankers and specific vessels accessing the Alcoa jetty.

Last year, the Port initiated a major enhancement to adopt the latest DUKC technology, which enables any ship to be able to use DUKC in the channels that were at that time under this control. Simultaneously, the Kwinana Bulk Terminal facility was included into the system. Consequently, the final result is that all channels and berths, which can benefit from the use of DUKC, are now covered by the Port system.

The technology of DUKC Series II is not constrained to being able to only simulate classes or groups of ships in determining the under-keel clearance predictions. There is now virtually no restriction as each ship is simulated individually using its own unique hydrostatic and load criteria for the time of the channel transit.

Typically, ships and their conditions that would be applicable to the use of DUKC Series II would be:

Container vessels to or from the Inner Harbour at a draft = 12.50m.
Vessels accessing or departing Alcoa jetties at a draft > 10.97m *
Vessels accessing or departing Kwinana Bulk Terminal (KBB2) at a draft > 10.97m *
Tankers of beam = 40m at a draft = 13.0m.
Bulk carriers arriving for or departing from Kwinana Bulk Jetty at a draft = 13.0m *
Bulk carriers departing from Kwinana Grain Jetty at a draft = 13.0m *

* Ships with drafts slightly in excess of these nominated values may be able to conduct channel transits under published parameter conditions (not using DUKC) but are likely to be constrained by tidal height and incur consequent delay.

The DUKC Series II facility has two main functions:

1. Identifying the maximum draft that a vessel can load to in the forthcoming 24 hours, and

2. Nominating the tidal window available for a channel transit for a lesser draft than the maximum.

Note, if loading to the maximum draft, vessels must depart at the nominated time.

In addition to the above functions which are based on real time data of tide and wave climate, scheduling facilities are available which will give indicative probabilities of maximised draft values with sufficient lead time to plan optimisation.

For shipping trades that wish to maximise their draft on arrival, special provisions have to be made as Fremantle Ports has to be involved in nominating the maximum acceptable draft for a nominated arrival date. This is already common practice with the arrival of crude oil tankers, container vessels and chemical tankers to Alcoa.

In using either the import or export functions of DUKC, it is essential that forward planning is conducted with Fremantle Ports. The responsible person for contact at the Port is Capt. Eric Atkinson (phone 9430 3325, fax 9430 3450 or e-mail: EAtkinson@fremantleports.com.au).

As indicated above, DUKC Series II calculates a simulation prediction of under-keel clearance on a unique basis dependent upon the individual ship and its load condition. Consequently, there is a requirement for specific data to be made available to the Port at the earliest opportunity to enable the process to be pragmatically conducted.

The procedure to be followed when nominating an export vessel will be:

Vessel to be nominated by agent giving at least seven days notice, advising of anticipated loading (or arrival) date.

Agent to arrange, for the following information to be provided by the vessel to Fremantle Ports at the earliest opportunity:

The anticipated departure draft.
The vessel's displacement tonnage at the departure draft.*
The vessel's transverse centre of gravity (KG) in its anticipated load condition.*
The vessel's metacentric height allowing for free surface effects (GMf) in its anticipated load condition.*
The length of the vessel between perpendiculars (LBP).
The beam of the vessel.

Fremantle Ports will determine the best maximum draft for the vessel in conjunction with the vessel's agents, taking into account waiting time that may be incurred when maximising drafts.

If the nominated best maximum draft advised by Fremantle Ports is at a variance of greater than 30cm from that of the original anticipated, the requested data items marked * will have to be revised.

When nominating a vessel for an import, the above procedure needs to be preceded with planning consultation with Fremantle Ports to ensure that the vessel has loaded to an acceptable maximum draft. It will be appreciated that this process must be undertaken some time prior to the loading of the vessel, which may be some weeks before its arrival at Fremantle.

When container vessels require to use DUKC Series II, the vessel characteristics and stability data will be required in the same manner as for other vessels.