TheDecisiontoSortieorRemaininPort
THE DECISION TO SORTIE OR REMAIN IN PORT
General
The Townsville Port Authority has developed a Cyclone and Evacuation Procedures Manual. The document gives detailed instructions on actions to be taken prior to the start of the tropical cyclone season, and procedures to be followed during a tropical cyclone threat scenario. The Port of Townsville utilizes three standard Conditions of Readiness (COR): Green, Yellow, and Red. A fourth COR, Blue, is a secondary alert condition apparently unique to Townsville. The following COR descriptions are taken from Townsville Port Authority (1997a).
Condition GREEN- Condition Green is in effect routinely between 1 December and 1 April every year. However, a state of normal vigilance operates between cyclone seasons.
Condition YELLOW - A yellow alert will be issued by the Emergency Management Team to indicate an intensifying risk of a cyclone, or associated weather storm impacting on the Port of Townsville and that specific actions must be taken to minimize the consequences. Included in the specific action list is the following: "Ships' Masters: Bring crews to full complement, prepare to put to sea. Comply with the directions of the Regional Harbor Master. Ships to put to sea if directed by Regional Harbor Master. If instructed to remain in port, comply with Annex B" of the Cyclone and Evacuation Procedures Manual.
Condition BLUE - A secondary alert condition. The Regional Harbor Master, at his sole discretion, may direct that ships in the Port of Townsville must put to sea, and that shore-based resources to enable this are to be mobilized. The Harbor Master exercises this discretion on the basis of a deteriorating opportunity for safe evacuation of ships in increasing winds within the confines of a narrow channel and the lead time required to complete the operation. Condition Blue should not affect residual operations of the Port and the continuing flow of actions in accordance with Condition Yellow.
Condition RED - A Condition Red alert will be declared when a cyclone strike is imminent. This also includes the impact of extreme, peripheral weather conditions associated with a high intensity cyclone. A RED Alert signals the requirement for immediate evacuation of the Port. During a November 1997 port visit, it was emphasized by local harbor authorities that ships moored in the port will be ordered to sortie and evade any threatening tropical cyclone at sea whenever Condition Red is declared. It should be noted that it does not necessarily follow that Condition Red will be called for every expected direct impact of a cyclone; e.g., it may not be called for lower intensity occurrences.
When a sortie is not mandated by the Regional Harbor Master and is, instead, left up to the discretion of the ship's commanding officer or master, the decision on whether to sortie or remain in port is largely based on the answer to a single question: Would the vessel in question be better off by evading at sea or by remaining in port? Many factors should obviously be considered, including (1) the seaworthiness of the vessel, and (2) whether adequate lead time is available to allow the sortieing vessel to exit the Port of Townsville and the Sea Channel, and gain sea room before the strong winds and high seas from the approaching tropical cyclone reaches the proposed evasion route. When planning a sortie, many factors should be considered, including vessel characteristics, the most recent tropical cyclone warning, tropical cyclone climatology, and the seaworthiness of the vessel. Evasion rationale should include consideration of the following general factors:
- Vessel characteristics
- Berth and anchorage conditions
- Most recent hurricane warning advisory
- Tropical cyclone climatology
Individual vessel characteristics and berth/anchorage conditions are best determined by those responsible for each vessel and local port authorities. Tropical cyclone warnings are issued by the Naval Pacific Meteorology and Oceanography Center/Joint Typhoon Warning Center Pearl harbor for the U.S. Government and by the Australian Bureau of Meteorology Brisbane Tropical Warning Center. The interpretation of tropical cyclone climatology is addressed in the following sections.
Evasion at Sea
It is the recommendation of this evaluation that all U.S. Navy ships sortie from the Port of Townsville whenever the Townsville is threatened by an approaching tropical cyclone. The orientation of the coast of Queensland and the existence of the Great Barrier Reef limit the sortie options of ships in port at Townsville. In all sortie cases, the timing of the evasion is affected by:
- The time required to make preparations to get underway.
- The time required to reach open water and gain sea room.
- The forward speed of the tropical cyclone.
- The radius of hazardous winds and seas that can adversely impact a vessel's ability to reach open water.
Commanding officers and ship masters with access to tropical cyclone warnings and advisories coupled with OTSR services are most capable of making the safest and most prudent decision for successful storm evasion and avoidance. In all sortie situations, OTSR services from Naval Pacific Meteorology and Oceanography Center (NPMOC), Yokosuka should be requested and utilized. The best sortie route in a specific tropical scenario is largely dependant on the location of the tropical cyclone and the forecast track. During any tropical cyclone threat there is normally one to three options available to the commanding officer and ship master. Selection of the best option is the objective of all concerned!
For Townsville the following guidelines are offered:
a. Tropical cyclone approaching from northeast or east.
Sortie as early as possible and steam northward into deep water via Palm Passage. If a storm develops rapidly just off the coast and precludes this option, staying in the channel between the Great Barrier Reef and the coast is another option with transit to the north or south depending on forecast of storm. This option is balanced by few passage routes to deep water, but reduced impact of swells.
b. Tropical cyclone approaching from north, northwest or west.
Sortie into the Coral Sea as early as possible and steam northeast or eastward, placing as much distance as possible between the sortieing unit and the tropical cyclone. The vessel will likely be placed on the dangerous left side of the storm's circulation, so adequate clearance is necessary to avoid the storm's worst effects.
Remaining in Port
Remaining in port during a tropical cyclone threat is an option that is usually not available at Townsville. As stated above, any time Condition RED is declared, all ships will be directed to evacuate the port. If an approaching tropical cyclone is relatively weak, Condition RED may not be declared, and ships may be given the option of remaining at their berths. However, it is the recommendation of this evaluation that all U.S. Navy ships berthed at the Port of Townsville sortie well in advance of the arrival of any tropical cyclone, regardless of intensity.
Source: http://www.nrlmry.navy.mil/port_studies/thh-nc/australi/townsvil/text/sect8.htm
