Ship Safety Assessment At Thilawa Port Approach Channel

After 1988, Myanmar has changed her policy and adopted the market-oriented economic system. Yangon Port is hub port of international and coastal shipping. Due to the increasing volume of external and internal sea-borne trade, Myanmar government has expanded the port infrastructure to meet with the requirements of shipping trade. After 1997, Myanmar became a full-fledged member of ASEAN and promoted ASEAN Tourism. The Ministry of Hotels and Tourism and the Ministry of Transport sponsor cruise tourism in Myanmar. Therefore cruise ships and their extended activities on land are a new phenomenon which makes the use of Myanmar port increase.Myanmar government has established the Thilawa Special Industrial Zone. Then it will be become the export concentration zone and 1/3 of import and export cargoes will be handled by Thilawa port. The significant of Thilawa port are reduce navigation time, reduce the fairway anchorage waiting time, avoid the traffic congestion and accommodate the large size container ships and cruise ships. Before 2001, Myanmar Port Authority (MPA) allowed ships with LOA of 167 meters and maximum draught of 9 meters to enter Yangon channel. At present, MPA considers large type vessels to allow berthing at Thilawa port case by case to satisfy with the demands of shipping trade.For the development of Thilawa Special Industrial Zone and meeting the requirement of ASEAN cruise tour, the transportation capability and safety channel navigation in the Yangon river entrance channel should be solved. Thus, it is necessary to research for the width and depth of Yangon channel.The main contents of this dissertation are as follows.■Analysis the safety of Yangon river entrance channel by using fuzzy synthetic evaluation method.■To satisfy the large type vessel's requirement, the required channel width and channel depth will be derived out by applying ship handling simulation research.■Under the present channel and tidal circumstances, large type vessel's required turning range, sailing time and tide level will be analyzed by using simulation research under the different condition.Yangon channel is a river channel and is the main entrance channel to Yangon port. Thilawa port is strategically located in the south east of Yangon city and on the Yangon river, about 8.6 nautical mile downstream from Yangon port. It closes to the mouth of the Yagnon river and adjacent to the Thanlyin-Kyauktan special industrial park.Myanmar possesses the monsoon climate with three main seasons. During monsoon season, the tropical storms are formed in Bay of Bengal and their effect suffered Yangon and coastal region for 3～5 days. From about May～October, the very warm damp south-west monsoon blows and from November～February governed by the north-east monsoon. The maximum wind speed reached 34.7～43.5 nautical mile/hours. The precipitation is 147 days in the whole year and 90～95% of the rain fall is concentrated in the period of May to October.The Yangon channel has limitation on the draft clearance at outer bar and minimum depth is 5.18 m. The 4.6 meter below chart datum level was recommended by the final report of Sir Alexander Gibb & Partners and NEDECO joint consultants' team survey record (1982) and 8.5～9 meter of vessels permit to cross the two bars on more than 80% of all high tides at any time of the year.The vessel traffic system is formed by ship, mariner and traffic environment and they are interaction between each other. Vessel is basic factor of the structure of vessel traffic system. Due to the various types of vessels, all of their specifications are not the same, with the consequent navigation risk of complex traffic environment. Vessel traffic environment is guided to the condition of ship maneuvering area which contains sea lane environment of navigation area, natural condition and traffic condition. In addition, traffic environment is a main influence factor on the traffic safety.The narrowest point is located in Hmawun Lump bouy with 650 meters width, where a 39°course alteration is required. The traffic volume in Yangon channel is about 80 vessels per day.During this study, focus on the integrated evaluation of the whole channel and each of four channel segments. By applying the fuzzy synthetic evaluation method, analyses the channel safety of present channel situation under the influent of difference type of environmental factors, natural condition of channel situation and traffic flow. Consequently, it will be provided for better safety navigation and prevented the ship accidents caused by the vessel traffic system including mariners, ships and environmental factors.Although the evaluation method is simple, the result of integrated evaluation gives encouraging effectiveness to prevent ship accidents. For the analysis of each channel, the result of risk level for Middle bank and Hmawun channel are medium stage. Moreover, evaluating result of risk level for the whole channel does not reach high stage under the present situation.The ship simulation research, in the Yangon river approach channel, with respect to the sailing, berthing and unberthing process by applying ship simulator is the effective science method. To meet the large type vessel's requirement and according to the "Design Code of General Layout for Sea Port", the required channel width and channel depth will be derived out by applying ship handling simulation research. According to the Yangon harbor plan and developing trend of container transport, the suitable design ship type especially ship dimension and draft will be selected and carry out the research work and comparison. Moreover, under the present channel and tidal circumstance, the large type vessel's required turning range, sailing time and tide level will be analyzed by using simulation research under the different condition. This study indicates that calculating method of Yangon channel width is reliable.In Elephant point, the average tidal range is 5.76 m (18.9ft) at spring tide and the mean tidal range is 4.27 m (14ft). Vessels depart from Yangon port has to cross outer bar in time and they abide the channel regulation and calculate the high tide to ensure sufficient depth. Since the distance between inner bar and outer bar is about 17.38 nautical miles, vessels navigate with high speed can cross both of bars but low speed vessels will anchor and wait for the required high tide. Due to the characteristic of Thilawa port, vessels enter Thilawa port necessary to wait the sufficient height of tide.Based on the 2002 to 2006 tidal information, the commutative highest high tide level provides the design tidal level of Yangon river channel. According to the situation of tide and tidal current of Yangon River and surrounding area, analyses the 24 times of simulation. The result is required ship sailing time for Yangon river channel from fairway to Thilawa port and Thilawa port to fairway under the different simulation process. The required tide levels of design ships are boundary within the design height of tide and can safely enter the Thilawa port with one tide. The design height of tide provides valuable reference for safety of entering vessel.In the research process, some navigation risks exist in the Yangon entrance channel:1. A vessel of accessible maximum LOA is 180 m and maximum draught is 9.5 m.2. The draught of vessels entering the Inner Harbor is controlled by the available depths at Inner Bar, Monkey point channel with 3.96 m (14 ft) below chart datum and entering Outer Harbor is controlled by the available depths at Outer Bar with 5.18 m (17 ft).3. Yangon channel is a river channel and the tides are semi-diurnal. Spring tide current is 2 m/s to 3 m/s.4. Minimum navigable channel width is situated in near Hmawun lump buoy with 650 m and also need 39°course alternation.5. The fishing vessels' traffic lane passing through the turning area of in front of MITT wharf.6. Non-machine fishing boats and fishing gears are situated along the Yangon river approach channel.7. Erosion at some portion of meandered river banks and siltation at some foreshore areas. Sedimentation at some locations of the navigational channel.8. During monsoon season, the maximum surface wind speed reached 40 to 50 mph (34.7～ 43.5 nautical mile / hour) and mean precipitation is 147 days.9. There are many delay time in Yangon port caused of insufficient cargo handling equipments and lack of cargo storage area. According to the 2001-02 statistics, maximum delay time of cargo handling is 63 hours in Yangon port.For the safety of navigation in the Yangon entrance channel, should abide the following safety measurements:1. Abide the harbor regulations relevant to the pilotage, traffic lane and safety traffic communication. When vessels navigate in channel or approaching wharf, they should respect and abide the regulations for preventing collision and other traffic regulations. They must clearly express ship behavior, facilitate with skill person and channel navigating facilities and tugboats assistance. They should conduct with closely co-operate with port authorities and with each other.2. When vessels enter the harbor, choose the appropriate time for navigation such as the minimum influence of environmental factors (wind, current and visibility). If it can navigate, choose in day time or minimum influence of current.3. During the maximum traffic density, increase the co-operation with other vessels of near channel area.4. To ensure the safety of vessel, the navigational aids and marks should be set up along the approach channels and they must be clearly identify and provide for the safety of navigation.5. Strictly abide and respect the speed limitation and safe speed regulation in harbor area.6. To ensure the safety of navigation, estimate and take the advantages of wind, current and leeway.7. Ship drifting is important factor that should be affected to ship approaching to and departing from wharf. While approaching to wharf the minimum current influences is appropriate for the ship maneuvering and take tugboat assistance.8. To ensure the safety of berthing and unberthing, take the sufficient tug boat assistance.9. Every vessel should make sure to maintain a proper look-out. To maintain the correct route plan, it should often take the present ship position by using GPS, Radar, Echo-sounder and communication equipment.10. During monsoon season, choose an appropriate shelter and anchorage to avoid bad weather.11. Communicate by the effective VHF, communication equipment with harbor authority and closely cooperate with other sailing vessels and tugboats.12. Prepare for emergency situation in the event of ship accidents, such as main engine failure or rudder failure. 13. Prohibit the vessel arriving at and departing from harbor while the visibility is less than 500 meter.14. While navigating in harbor approach area, the maximum wind speed should not be exceeded wind scale 7 and vessel has to navigate with minimum speed 6 knot. And also wind scale should not exceed 6 while berthing & unberthing situation.15. For the vessel's safety in channel navigation, MPA should implement to channel dredging work.From this study, we can conclude as follows:Channel risk levelAccording to the result of integrated evaluation of channel safety condition, although the risk level of Middle bank channel and Hmawun channel are medium stage, evaluated risk level for the whole channel does not reach high stage under the present channel situation. With the development of new wharves in Yangon port, the traffic volume of study area will increase and the integrated evaluation result will need to be reconsidered.Channel width and channel depthFrom the simulation result, the required one-way and two-way channel width of 68,000 DWT cruise ship exists in the boundary of channel design width. The required channel depth of cruise ship is 8.8 m. Therefore the natural depth is not satisfied with the required depth of design ship and it will need the sufficient tide level to pass the outer bar (5.18 m). The dimension of turning circle, in front of MITT wharf, is sufficient with the design value and depth of turning area is also adequate depth for design ship.Sailing time and required tide levelAccording to the situation of tide and tidal current of Yangon river and surrounding area, analysis has been made 24 times of simulation. The required ship sailing time for entering Yangon river channel from fairway to Thilawa port is 2:00～2:20 hours (with tide) and sailing time for out-going channel from Thilawa port to fairway is 2:10～2:39 hours (against tide) According to the four year tidal information analysis, the design height of tide level is 510 cm. The required height of tide for design ships are boundary within the design height of tide and can safely enter the Thilawa port with one tide.This paper is, under the present channel condition, the safety navigation for the maximum tonnage of vessels to enter the Yangon channel. According to the ship simulation results, it can be clearly pointed out the inadequate facilities of channel condition and requirements of the channel implementation as well as it will provide the authority concerned with the decision making in order to make better economic benefits and implementation of channel safety.In summary, the Yangon channel width is satisfied with the 68000 DWT cruise ship's requirement. It is noted that the maximum draft of ship is 9.5 m. The natural depth of Yangon river entrance channel is not satisfied with all of entering vessels and they also need the sufficient height of tide level. But, Yangon channel is not affected on thel5000 DWT vessels and not more than 9.5 m draft vessel.