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BUNBURY

THE DECISION TO SORTIE OR REMAIN IN PORT

General

Under normal circumstances, 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 attempting an evasion at sea or remaining in port? Evasion rationale should include consideration of the following general factors:

1. Vessel characteristics
2. Berth and anchorage conditions
3. Most recent tropical cyclone warning advisory
4. 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 Perth Tropical Warning Center. The interpretation of tropical cyclone climatology is addressed in the following sections.

Evasion at Sea

Evasion at sea is not the recommended course of action for ships in the Inner Harbor. However, ships at anchor or berthed in the Outer Harbor should move to a protected berth in the Inner Harbor or sortie in the event of an approaching tropical cyclone.

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 cyclone scenario is largely dependent 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!

Keeping in mind that tropical cyclones normally approach the Port of Bunbury from the northwest, the following guideline is offered: An evasion route to the west-southwest would provide following wind and sea for almost all approaching tropical cyclone situations.

In all cases, the timing of the evasion is affected by:

1. The time required to make preparations to get underway
2. The time required to reach open water and gain sea room
3. The forward speed of the tropical cyclone
4. The radius of hazardous winds and seas that can adversely impact a vessel's ability to reach open water.

Remaining in Port

Remaining in port is the recommended course of action for ships in the Inner Harbor. Berths 5 and 8 are the preferred berths if a ship decided to remain in port. These berths have excellent fenders and according to the Harbor Master vessels are "comfortable" in winds up to 60 kt and do not encounter major problems with gusts up to 80 kt. Except in severe tropical cyclone cases, berths 5 and 8 in the Inner Harbor should provide excellent shelter from the effects of tropical cyclones affecting Bunbury.

Note that safe wind limits for remaining alongside are best left to the judgement of the commanding officer or ship's master and the Port of Bunbury authorities. A sortie is recommended if any doubt exists as to the strength of an intense topical cyclone or its impact at a particular berth.

Source: http://www.nrlmry.navy.mil/port_studies/thh-nc/australi/bunbury/text/sect8.htm