Questions about channel deepening and underwriting risks
Australia's Victorian Government appointed two Panels in 2004 and 2007 to consider the Port of Melbourne (PMC) proposal to deepen the shipping channels from the Entrance of Port Phillip Bay in the south to the container ship berths at Appleton Dock in the north, and to consider the potential environmental and financial consequences that could result.
The proposal is to allow an increase in the maximum draught of ships using the port, at all stages of the tide, from 11.6 metre to 14 metre.
Following receipt of the two Panel Reports, the Victorian Government granted approval to the Port of Melbourne Corporation to proceed with deepening the shipping channels, in accordance with their submitted channel designs and operating parameters, and to engage the Dutch dredging company 'Boskalis' to carry out the dredging work.
The following comments relate specifically to the safety of navigation of near 14 metre draught ships transiting the Great Ship Channel entrance to Port Phillip and to the potential environmental, financial and social consequences that may occur if these vessels fail to navigate safely through this Channel.
The entrance to Port Phillip is recognized as one of the most difficult and dangerous port entrances world-wide. The cross currents on the flood and ebb tides in the entrance, at times exceed rates of 8 knots and flow diagonally across the Great Ship channel in two opposing directions, simultaneously. Times of high and low water, when the currents are flowing at their maximum, can differ from the predicted times by as much as 60 minutes, due to changing atmospheric pressure systems and prevailing winds. Surface tidal currents oppose the direction of the bottom currents, close to the times of change of tide.
There is factual, electronic and anecdotal evidence that vessels with less than the maximum draught of 11.6 metre are currently being set by the cross currents outside the boundaries of the Great Ship Channel into the Eastern and Western Channels. Mostly these ships will not strike the sea bed due to the existing depths of water in the side channels.
Once the Great Ship Channel is deepened, (but not widened, as proposed by the PMC) for the use of 14 metre draught ships to transit, there is no doubt that the deeper draught vessels will more likely be set into the Eastern and Western Channels and will ground in the shallower water unless these two channels are also deepened to the same depth as the Great Ship Channel.
The Permanent International Association of Navigation Congresses (PIANC) in its publication, 'Guide for the Design of Approach Channels', considers the effect of cross currents in excess of 1.5 to 2.0 knots to be too strong, for the application of their empirical design rules.
In such difficult environments, the PIANC Guide recommendations require the use of ALL available local data and knowledge and testing by simulation trials to determine individual safe entrance channel design widths. These PIANC 'Recommendations' have not been fully complied with in the Entrance Channel design process.
Notwithstanding the Government's acceptance of the two Panel Reports and the PMC proposal there are many serious concerns and unanswered questions expressed by pilots, other professional mariners and hydrographic surveyors, with the safety of the 'approved' entrance channel design, and with the proposed operating parameters for near 14 metre draught ships to safely transit the Entrance to Port Phillip Bay.
Accepting the legitimacy of these concerns, the question of responsibility and liability must be examined for the potential causes (including a flawed channel design and flawed operating parameters) of a near 14 metre draught vessel grounding outside the boundaries of the Great Ship Channel and also for the potential consequences, including a shipwreck and the release of large quantities of oil. Attributing such an accident to an "Act of God" if the ship is set outside the boundaries of the Great Ship Channel and grounds in the side channels is unacceptable.
Ship owners and marine underwriters must take a close look at reduced safety margins and increased risks and the areas of responsibility and liability, and authorities must be aware of the potential economic, environmental and social consequences.
Dredging commenced on the February 8, 2008. At the start of April 2008 the project was referred to the Victorian Government Standing Committee on Finance and Public Administration for the Committee to examine the 'Business Case', as advanced by the Port of Melbourne Corporation.
The reduced safety margins and increased risks associated with the proposed channel design and the proposed operating parameters of a near 14 metre draught vessel transiting the Heads, have not been properly investigated: they are not fully understood and have not been taken into account in arguing the business case. The failure to cost risk in the business case precludes the business case complying with government and industry standards.
These deficiencies undermine the credibility of the design process for the channel at Port Phillip Heads and there is little confidence in the project securing an adequate level of ship safety and maintaining safe financial, environmental and social standards.
The safety of near 14 metre draught ships transiting Port Phillip Heads is being compromised and all parties including governments, ship owners and marine insurers need to be fully aware of the increased level of risk and the potential consequences.
The author of this paper is Captain Frank Hart, former Harbour Master of the port of Western Port and Hastings. His assertions in this report are supported by evidence provided by several former Port Phillip Pilots.
August 2008.
See also: www.bluewedges.org.
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