TheDecisiontoEvadeorRemaininPort
MURORAN
THE DECISION TO EVADE OR REMAIN IN PORT
General
There is no U. S. Navy authority assigned to Muroran, so decisions to evade or remain in port will necessarily be made independently by the ship's captain in accordance with appropriate directives issued by higher authority.
Evasion Rationale
It is of utmost importance that the commander recognize the inherent dangers that exist when exposed to the possibility of hazardous weather. Proper utilization of meteorological products, especially the NOCC/JTWC Guam Tropical Cyclone Warnings, and a basic understanding of weather will enable the commander to act in the best interest of the unit, and complete the mission when the unfavorable weather subsides. To assist in preparation for the threat posed by an approaching tropical cyclone the following time/action sequence aid, to be used in conjunction with Figures V-142 to V-143, is provided.
I. An existing tropical cyclone moves into or development takes place in Area A with long range forecast movement toward Muroran.
a. Review material condition of ship.
b. Reconsider any maintenance that would render the ship incapable of riding out a storm or typhoon with the electrical load on ship's power, or would render the ship incapable of getting underway, if need be, within 48 hours.
c. Plot NOCC/JTWC Guam warnings when received and construct the danger area. Reconstruct the danger area for each new warning.
II. Tropical cyclone enters Area B with forecast movement toward Muroran (recall that tropical cyclones tend to accelerate rapidly after they have recurved):
a. Reconsider any maintenance that would render the ship incapable of getting underway, if need be, prior to the onset of strong winds within the harbor. If a sortie is planned, it should be initiated soon after the storm enters Area B.
b. Plot NOCC/JTWC Guam warnings when received and construct the danger area. Reconstruct the danger area for each new warning.
III. Tropical cyclone has entered Area C and is moving toward Muroran:
a. Anticipate the arrival of the tropical cyclone winds and take appropriate actions.
b. Plot NOCC/JTWC Guam warnings when received and construct the danger area. Reconstruct the danger area for each new warning.
A strong wind is the most important factor to be considered. Wave action has only limited effect in the port of Muroran, especially at Sakimori berths 1 and 2, and storm surge effects are negligible.
Remaining in Port
As related above, harbor personnel state that merchant seamen regard Muroran to be the best port in Hokkaido. The port has successfully been used as a haven over the years by various ships, including a British ship that, according to harbor personnel, entered the port during "typhoon conditions" in 1991. Typhoon occurrence at Muroran is infrequent, but it does happen. Local harbor personnel relate an incident that occurred "about 40 years ago, when DoYamaru typhoon gave large damage to ships." Such an incident is an indication that although most storms would not pose a serious threat to ships in the port, it is possible for a particularly strong tropical cyclone to cause significant damage. There are no specifics regarding the location or size of the damaged vessels.
In consideration of the foregoing, the safest course of action would be for seaworthy ships to sortie from the port prior to the arrival of strong winds and evade at sea. If a vessel could not get underway, it should take normal precautions for high winds. The strongest forces would probably have a strong west or east component, although a strong southerly wind is possible. A southerly wind would tend to force the ship onto the pier, while easterly or westerly winds would be along the longitudinal axis of ships moored to Sakimori piers 1 and 2. Extra attention should be given to the brow and mooring lines during the passage of the storm. Ships should put out extra line and wire as deemed necessary and should be ready to tend mooring lines.
Evasion at Sea
Evasion at sea is considered to be the wise and safest course of action. An early sortie from the harbor will provide the captain with several evasion options that will not be available if sortie is delayed. It must be borne in mind, however, that tropical cyclones are historically unpredictable, and the 48-hour forecast position error often exceeds 200 nmi. Because of this error, a storm could be closer to (or farther from) Muroran than the forecast indicates or be right or left of the storm's forecast track. Tropical cyclones may cross the mountainous terrain of Honshu, moving from the Sea of Japan to the Pacific Ocean, and from the Pacific Ocean to the Sea of Japan. Consequently, the prudent mariner will plan ahead, sortie early, and include back-up options in his planning in case the tropical cyclone does not follow the initial forecast track.
The cooler surface water and cool air found at higher latitudes cause tropical cyclones to lose their tropical characteristics, with a resultant weakening and ultimate dissipation of the tropical cyclone. Caution is necessary, however; even though a circulation has lost it's tropical identity, it may still be accompanied by storm force (47 kt) winds.
Evasion routes at sea may be developed by the use of the NOCC/JTWC Guam tropical cyclone warnings, and Appendix A (the mean tropical cyclone tracks, track limits, and average speed of movements) for the month of interest in conjunction with Figures V-142 and V-143 (tropical cyclone threat axis and approach times to Muroran). In each specific case, Optimum Track Ship Routing (OTSR) should be consulted as to the best evasion route.
If the tropical cyclone is approaching Muroran from the south or southeast on the Pacific Ocean side of Japan, a recommended evasion course would take the ship through the Tsugaru Strait into the Sea of Japan. Such an action would place the ship in northerly flow on the weaker left semicircle of the storm's circulation while moving away from the storm center. An evasion course to the east of Japan is not recommended since it would place the ship in a vulnerable position north of the storm.
If the tropical cyclone is forecast to approach Muroran across the Sea of Japan, a recommended evasion course would take the ship east and south along the coast of Honshu. If such an option were chosen, it must be initiated early because of the liklihood of encountering southerly head winds and seas that will only become stronger as the storm approaches.
Source: http://www.nrlmry.navy.mil/port_studies/thh-nc/japan/muroran/text/sect4.htm
