Many projects have been proposed and suggested so far, to improve navigation safety in the straits of Malacca and Singapore. However, we have recognized studies so far based only on their qualitative effects, and not based on their quantitative effects.

　

 These days, it has become common rule in many countries that every public works project needs cost-benefit assessment before making the political decision to start. Furthermore, regarding the Straits, it is more important to grasp the quantitative effect of each project for the user States and user industries, who are expected to contribute to the projects.

　

 Our study aims to show the quantitative cost benefits (B/C) of the projects, using the method used generally by the Japanese government.

　

 Regarding the method of the cost-benefit analysis, we used two guidelines, which were established and generally used by the Japanese government in their public works project in the maritime field.

　We carried out cost benefit analysis on following four projects, which are prioritized and requested by the Japan Captains' Association (JCA), as they are experts of the navigation of the Straits.

 Two from the projects proposed officially by the littoral States at the IMO-KL meeting;

 And two projects requested by JCA;

 The first project is the removal of wrecks in the TSS which was proposed by the littoral States. Although the original proposal has twelve wrecks in total, we consulted the JCA for their opinion, to select four wrecks with high priority for removal, as follows;

　

　

 The first wreck is numbered 1 in the list proposed by the littoral States, located in the east-bound lane near the One Fathom Bank. Because of this obstacle, the lane is divided in two, one north and one south, making the effective use of the lane's full width for navigation not available. By removing this wreck, it is expected that the navigable area for large ships will widen, resulting in less density of traffic and safer navigation.

　

 The next wreck is named MV Royal Pacific. Because east-bound deep-draft ships must steer largely to the right near this point to the direction of the DW lane, they must cross the course of other ships going straight to the direction of the SW lane. By removing this wreck and widening the navigable area, it is expected to reduce the risk of collision.

　

 The next two wrecks are numbered 7 and 9. East-bound deep-draft ships usually navigate, whole of the Straits, by adjusting the time so that they enter the Singapore Straits at the time of high water to keep enough Under-Keel-Clearance (UKC) in the area of Singapore Straits, which means that they cannot navigate though the lane near these two wrecks during the time of high water. Therefore many large ships cannot keep the UKC of 3.5-meter over these two wrecks. Furthermore, because the lane near these wrecks is particularly narrow, large ships are frequently obliged to change their course in order to avoid these wrecks.

　

 As for the cost of this project, figures proposed by the littoral States were US$ 4 million for the cost of investigation and US$ 15 million per wreck for removal, for a total cost of up to US$ 64 million to clear these lanes. Also we calculated the durable years of this project as twelve years for four wrecks in total, based on the survey on the frequency of the occurrence of wrecks in the Straits that become obstacles to navigation, which was about once every three years.

　

 This is the project currently carried out by the Malacca Strait Council (MSA), aimed to conduct the maintenance of the existing aids to navigation, and to replace those with which the durable years have expired.

　

 As for the cost of this project, the original proposal at the IMO-KL Meeting estimated the accumulated figure for ten years from the present year 2007. However, this study is supposed to be set at 2020 as its goal year, so the cost for this project was calculated up to year 2020.

　

 This is the project top-prioritized by the JCA. There are two shallows, which are one of the most difficult stages of navigation in the Straits for large ships, and actually, a large percentage of the collisions of large ships occur near these two points.

　

 The first shallow is located in the north of the Batu Berhanti. Most of the east-bound container ships, which intend to enter the Port of Singapore, navigate through the SW lane, and steer largely to the left after passing the Batu Berhanti in order to enter the Port of Singapore. Such a ship usually slows down when turning left and crossing the DW lane, resulting in blocking the route of east-bound deep-draft ships. In addition, it will become very difficult to control the position of the ship due to the effect of strong tidal currents near here, resulting in nearing the shallow or entering the opposite lane, which are frequently occurring eases.

　

 The second shallow is located to the west of the Buffalo Rock. Because the shallow is located in the east-bound DW lane, east-bound ships passing the north side of the shallow often veer away from the shallow too much and happen to enter the west-bound lane. On the other hand, west-bound ships tend to take the southem side of the lane or even enter the east-bound lane, because the west-bound lane takes a slight left turn ahead of this area and that will make the route shorter. Therefore, congestion of east-bound ships and west-bound ships is frequently seen in this area.

　

 The cost required for this project is estimated at US$ 43 million, by calculating the dredging cost for the amount of soil volume dredged based on the area of shallows that are less than 24-meters deep according to nautical charts.

　

 The second project requested from the JCA is to replace the DW lane with the SW lane in the east-bound route. While this project is considered to have a significant effect once realized, because it must largely change the existing navigational rule, we decided to consider this project this time as an optional plan in the case where there is a large traffic increase in the future.

　

 The effect of this project can be given for various places within the Strait. The first point is at the entrance of the DW lane near the Racon D for east-bound ships. Currently, deep-draft ships navigate inside while shallow-draft ships navigate outside. However, many shallow-draft ships make a short-cut and go into the DW lane at this point, and that makes difficult navigation for deep-draft ships.

　

 Next, by replacing the lanes, it will become possible for east-bound deep-draft ships to keep a sufficient distance from west-bound ships throughout the TSS. Also, near the Batu Berhanti, it will make it possible to avoid the crossings of east-bound shallow-draft ships, passing the Batu Berhanti before entering the Port of Singapore, and east-bound deep-draft ships that go straight, as I explained with the previous project.

　

 Furthermore, for shallow-draft ships leaving the Port of Singapore and entering the east-bound lane, their routes will not cross with those of deep-draft ships when the DW lane is located outside and deep-draft ships are in the outside lane.

　

 Regarding the cost of this project, it requires dredging of several points in the TSS, and it is estimated to cost US$ 322 million.