Effect on Existing Marine Navigation for the South Soko Location

D1 Marine Navigation

D1.1 General

The principal hazards associated with a LNG carrier underway to and from a terminal within Hong Kong waters have been adopted as guiding criteria for site assessment. The following assessment parameters have been adopted to assess marine access to the sites:

· Marine Traffic (Carrier striking or being struck by any self propelled ship whilst underway to an LNG terminal within Hong Kong territorial waters, or at anchor);

· Grounding (when the carrier comes to a complete stop during transit to/from the terminal and is no longer able to manoeuvre) as a result of impacting the seabed or shoreline;

· The LNG carrier striking a navigation aid or the jetty structure, and

· Striking moored LNG Carrier by passing traffic.

Although no breach of containment has occurred from collision incidents in over three decades of LNG carrier operation, release of LNG is possible if there is sufficient penetration energy. That energy depends on the displacement, speed, design and angle of contact of the striking vessel.

The probability of the occurrence of a collision between LNG carrier and other vessel is governed by:

· Mechanical failure (propulsion or steering gear);

· Non-compliance with the Collision Regulations;

· Density of traffic within navigable waterway restricting room to manoeuvre;

· Environmental factors (visibility, current velocity and wind speed and direction); and

· Human error (pilot inexperience with carrier manoeuvrability, wrong helm instruction or incorrect application of helm command).

Grounding refers to the incident of an LNG carrier coming to a complete stop and no longer able to manoeuvre as a result of impacting the seabed or shoreline. Although no breach of containment has occurred from grounding incidents in over three decades of LNG carrier operation, there is potential for release of cargo after grounding. For a smooth seabed of sand or mud, penetration energy is usually spread over a large area of the carrier and with cushioning effect, penetration through the double hull into the containment system is less likely. Rocky bottoms cause more jagged penetrations with the impact being absorbed over a much smaller area and hence the greater risk for damage to the containment.

The probability of the occurrence of a powered grounding is governed by:

· Carrier draft versus projected water depth;

· Navigable channel dimensions;

· Navigation aids missing or not in charted position;

· Environmental factors (visibility, current velocity and wind speed and direction);

· Collision avoidance manoeuvre;

· Incomplete passage plan; and

· Inexperience of pilot with carrier manoeuvrability.

Impact with structures refers to the LNG carrier making unplanned contact with the channel approach or turning circle navigation aids (allision) or with the jetty during the approach manoeuvre.

The potential for a breach of containment as a result of a LNG carrier striking a fixed object in the vicinity of the terminal would be dependent upon the speed and angle of impact. In order for such an incident to occur, there would have to be a failure in navigational procedures, tug control, mechanical failure, or excessive speed during the approach manoeuvre.

Grounding incidents are not a common occurrence in Hong Kong waters given the provision of delineated navigable fairways, deep water and traffic control. The consequence of grounding at slow speed during the carrier approach and departure is unlikely to include breach of containment but could cause operational limitations if the outer hull is penetrated.

In the final approach to the jetty laden (arriving) LNG carriers should be under tug control and as such this hazard is of a lesser order than collision or grounding as significant damage to the LNG carrier hull is unlikely.

The probability of the occurrence for an LNG carrier striking the jetty structure during approach is governed by:

· Mechanical failure (carrier propulsion or steering gear);

· Environmental conditions (wind speed exceeds forecast, current velocity and direction not as predicted);

· Number and performance of assist tugs;

· Mechanical failure of tug(s);

· Human error (pilot inexperience in docking manoeuvre); and

· Excessive approach speed without parallel landing on fenders.

Impact resulting from an LNG carrier being struck while moored at the jetty is also a potential hazard. The factors impacting the potential for impact while moored are similar to those presented above for ship collision. The probability of striking the LNG carrier at the jetty is governed by:

· Proximity to other traffic;

· Nature and volume of local traffic;

· Metocean conditions;

· Level of ship handling experience on passing traffic personnel;

· Mechanical failure, propulsion or steering gear; and

· Passing traffic intruding into the prescribed safe distance.

D2 South Soko Island

D2.1 General

The passage of an LNG carrier to the South Soko Island site, based on pilot boarding south of Lamma, can be summarised as follows:

1) From entry to Hong Kong waters, approach to pilot boarding at South Lamma Dangerous Goods Anchorage - This is an open run that does require crossing the outbound ocean going traffic in East Lamma Channel from Hong Kong. No onshore populations are exposed in this node.

2) From pilot boarding at South Lamma Dangerous Goods Anchorage, transit through PRC waters south of spoil grounds, to re-entry to Hong Kong waters and run up the east side of South Soko Island before entering the start of a dredged approach channel on the east side of South Soko Island.

3) Turning basin and short tug assisted manoeuvre to South Soko Island Terminal and reversal to jetty with berthing operation.

The transit south of HKSAR waters will be undertaken in an “open sea” environment with low traffic density, although the crossing of small fishing vessels and fast launches is a concern (although not posing a hazard to the LNG carrier).

Transits to South Soko will require the passage of the LNG carrier within the Zhujiang Estuary Traffic Separation Scheme (TSS). This Scheme has undergone trials and is now being proposed for permanent implementation with the IMO. LNG carriers (assumed to approach HKSAR waters from the East) will enter the westward arm of the Dangan TSS (south of Lantau), and divert northwards near the termination of the TSS to pick up a pilot. The carrier will then re-enter Mainland waters and transit towards the entrance to the Lantau TSS. Just prior to the entrance to the TSS the LNG carrier will turn north to enter the dredged approach channel. For all access manoeuvres the LNG carrier will be travelling in a direction consistent with the TSS. On departure the vessel must cross the TSS to head eastward and should navigate in accordance with the Collision Regulations, Rule 10 (c).

The specific risks associated with each of the three site layouts at South Soko Island are considered in the following sections.

D2.2 Option 1 – Base Case

The approach channel is directly from deep water around the east side of South Soko Island to a turning basin immediately to the south of the Island, with a berthing pocket for the LNG carrier just off the jetty. The jetty is relatively well protected from the monsoon and typhoon waves from the Lantau Island from the north. The route to South Soko Island is largely open waters and there are few vessels.

D2.3 Option 2 – Full Reclamation

The jetty location is the same a Option 1 and therefore the risks are the same.

D2.4 Option 3 – SE Jetty

The approach channel is directly from deep water to a turning basin, with a berthing pocket for the LNG carrier just off the jetty. The jetty is not well protected from typhoon waves. However, it is considered that carriers will not be permitted at these times and will seek shelter elsewhere. The route to South Soko Island is largely open waters and there are few vessels.

D3 Summary for Marine Navigation

While comparing the sites at South Soko it may be identified that the Options 1 & 2 with the long curving dredged access channel pose a greater risk of grounding than the SE jetty. A summary of the parameter values and relative scores derived from the engineering assessment for the construction of the approach channel and turning basin is given in Table D1 below.

Table D1 - Summary for Marine Navigation

Parameter	Option 1 (Base Case)	Option 2 (Full Reclamation)	Option 3 (SE Jetty)
Marine traffic	RS = 3	RS = 3	RS = 3
Grounding potential	RS = 3	RS = 3	RS = 5
LNG carrier striking jetty	RS = 3	RS = 3	RS = 3
Striking of the moored carrier by passing traffic[TMO1]	RS = 3	RS = 3	RS = 3

RS = Relative Score

D4 Scoring for Marine Navigation

Each of the parameters summarised above in Table E1 have also been scored in accordance with the procedure described in Section 2.1.3. The results are shown below in Table D2 for each of the layout sites at South Soko Island. The table also shows the total score for each site derived using the weightings given in Table 2.6.

Table D2 – Scoring for Layout Options at South Soko Island for Marine Navigation

Parameter	Weight	Option 1 (Base Case)		Option 2 (Full Reclamation)		Option 3 (SE Jetty)
		Score	WS	Score	WS	Score	WS
Marine traffic	0.50	3	1.50	3	1.50	3	1.50
Grounding potential	0.10	3	0.30	3	0.30	5	0.50
LNG carrier striking jetty	0.10	3	0.30	3	0.30	3	0.30
Striking of the moored carrier by passing traffic	0.30	3	0.90	3	0.90	3	0.90
Total Weighted Score			3.00		3.00		3.20
Normalised Score		4.69		4.69		5.00

From the result of the assessment of all parameters for the marine navigation, it is found that Option 3 is the preferred layout.

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[TMO1]Per WDuncan: For consistency, propose amend the fourth parameter to read: 'Striking of the moored carrier by passing traffic'.