Maritime Terrorism in Southeast Asia: Potential Scenarios

Publication: Terrorism Monitor Volume: 4 Issue: 7

The MV Limburg was attacked by terrorists in the Gulf of Aden in 2002, an example of the threat posed by maritime terrorism.

In Southeast Asia, home to one of the world’s most strategic sea lanes—the Straits of Malacca, and the world’s second largest port, Singapore—the vulnerability of the maritime sector is of great concern. As a result, over the last few years various scenarios of how terrorists might carry out an attack in the maritime domain have been put forward by the media and academics alike. Many of these potential scenarios are extremely unlikely due to their complicated nature and their sheer impracticability. Nevertheless, a great number of these scenarios have remained unchallenged due to a lack of knowledge of the geography of the region, local shipping patterns and the nature of the commercial shipping industry in general. This has led to a misunderstanding of the threat posed by maritime terrorism.

This article seeks to address this problem by examining the credibility of a number of these scenarios. In addition, several other scenarios will be discussed which have received little or no attention in the literature on maritime security but which if carried out by terrorist groups could potentially have a serious impact on both Singapore and the efficient flow of global trade through the region’s strategic sea lanes.

Scenario: Ship Sunk to Block the Straits of Malacca

In an article in Singapore’s major broadsheet newspaper, the Straits Times on March 27, 2004, an “expert” on maritime security is quoted as saying that “If terrorists want to mount a maritime strike here [Southeast Asia], sinking a ship in the Malacca Straits is the likely attack of choice.” He goes on to say that “It would enable them to wreak economic havoc worldwide by blocking the sea lane, and is also the easiest way to attack.”

This scenario is clearly impossible for one key reason: the narrowest point of the marked channel in the Malacca Straits is at One Fathom Bank, where the width is 0.6 nautical miles. Even if a ship was sunk at this point, which itself is not necessarily an easy task to accomplish, it would not block the Straits. Ships could continue to use the waterway by simply navigating around the sunken vessel.

Scenario: Tanker as Floating Bomb to Strike Ports

The second possible scenario was summed up by Singapore’s Foreign Minister George Yeo in a speech given to the ASEAN Regional Forum on July 29, 2005: “Terrorists could hijack an LNG [Liquefied Natural Gas] tanker and blow it up in Singapore harbor. Singapore, of course, would be devastated. But the impact on global trade would also be severe and incalculable” (Ministry of Foreign Affairs, Singapore). As this statement implies, the potential threat of terrorists hijacking one of the many vessels passing through the region, particularly those carrying high-risk cargos, such as LNG, crude oil or other such inflammable chemical products, is of great concern to the Singapore government.

In addition, the high number of pirate attacks in the region, a number of which have involved the hijacking of these more high-risk vessels, has led to worry that terrorists could use copycat methods to takeover a vessel for more sinister reasons. In a visit to Malaysia in 2005, Vice Admiral Terry Cross of the U.S. Coast Guard told the media that the ease with which pirate attacks were taking place in the Malacca Straits could “alert terrorists to the opportunities for seizing oil tankers” and that “these could be used as floating bombs” (The Straits Times, April 18, 2005). In a similar vein, when the 1,289-ton MT Tri Samudra was boarded by pirates in the Malacca Straits, the regional manager of the International Maritime Bureau was quoted as saying: “This is exactly the type of tanker that terrorists would likely use to attack a shore-based port or other facility” (The Business Times Singapore, March 15, 2005). The Tri Samudra is a chemical tanker that was carrying a full cargo of inflammable petrochemical products when it was hijacked.

There are a number of issues related to this scenario that need to be considered when assessing how likely it would be and what particular form it would take. The first issue is the differing capacity of each vessel and its cargo to cause damage and the means by which this could be made possible by determined terrorists. The second issue is the actual impact on the port or facility itself.

LNG tankers and their potential role in a scenario of this kind have probably received the most attention. In its liquid state, natural gas is not explosive, and it is in this form that it is shipped in large quantities via refrigerated tankers. Once in the open air, LNG quickly evaporates and forms a highly combustible visible cloud. It has been reported that if ignited the resulting fire could be hot enough to melt steel at a distance of 1,200 feet, and could result in second-degree burns on exposed skin a mile away (Council of Foreign Relations, February 11). A fire of this magnitude would be impossible to extinguish. It would burn until all its fuel was spent. The impact of such a fire on a port like Singapore would be devastating. There would be loss of life and severe structural damage in the immediate area. This would mean that the port would have to operate at a reduced capacity, causing delays in trade and a loss of business.

The most likely way that terrorists would carry out an attack using an LNG tanker would be to create an explosion onboard the vessel as it is rammed into the target. If powerful enough this could rupture the hull and cause the gas to escape. The force required to breach the hull and tank, however, would almost certainly cause a fire at the tank location which would ignite the gas as it escaped rather than causing a cloud of fire or plume. Thus, the potential damage would be limited somewhat to the tanker’s location.

If the vessel chosen was an oil tanker carrying crude oil or petroleum products, its explosive capability would depend on the nature of the cargo and whether or not the vessel had a full load. Crude oil itself is difficult to ignite; its vapor, however, which may remain in the tanks after the vessel has unloaded its cargo, is more easily ignited. The most likely risk to the target port or facility is that of a localized fire, explosion (particularly in the case of volatile petroleum products), and the consequences of a potential oil spill.

The risk from a vessel carrying chemical products is also worrisome. Chemical products may pose a toxicity risk in addition to being highly volatile. Like LNG tankers, chemical tankers are designed with the maximum provisions for safety. The vessels are designed in such a way as to maintain space between tank walls to prevent incompatible cargos from coming into contact with each other. The safeguards in place, however, may not always be sufficient and may not be designed to guard against deliberate sabotage. In addition, general cargo vessels and container ships (which may not have such safeguards in place) are also sometimes used.

Scenario: Malacca Straits Blocked by Mines

One scenario that has not received much attention is the potential for the Malacca Straits to be blocked by mines. There are two variations of this scenario, both equally alarming. The first is that terrorists mine the Straits and the authorities are alerted to this fact either by a declaration from the perpetrators or because a ship hits a mine. The second is that terrorists merely claim to have mined the Straits and simulate a mine attack on a ship to add credibility to their claims. In each scenario, assuming that there is little or no information on the exact area of the Straits that has been mined, the impact would be the same—the Malacca Straits would be closed to shipping traffic, forcing the vessels, particularly those on international voyages, to reroute around the Lombok and Sunda Straits. This would cause severe delays to shipping as these alternate routes are longer. Additionally, shipping costs would increase and world trade would be affected. The impact on the region’s economies could be severe if the closure lasted more than a few days.

Scenario: Missile Launched at Aircraft from Vessel

The final scenario, and again one which has not been widely discussed, is terrorists using a portable surface-to-air missile (SAM), launched from a ship, to bring down a commercial airliner. This would be of concern to Singapore where planes coming into land must make their descent over the busy shipping lane—the Singapore Straits. While arrangements may be in place to reduce the possibility of a SAM being fired from the shore in Singapore, the same cannot be said about ships passing off-shore.

SAMs can be purchased on the black market for a starting price of $10,000 and have a range which puts aircraft that are landing or in a holding pattern waiting to land well within their targeting capability. The missile could be launched from one of the many hundreds of small vessels transiting the Singapore Straits. The impact on Singapore would be massive; not only due to the loss of life, closure of the airport and the immediate effect on the Singaporean economy, but because there would be no way of guaranteeing that a similar attack would not be carried out in the future. Short of inspecting the contents of every ship that passes though the Singapore Straits, the law enforcement agencies can do very little to reduce this particular threat.


The key to gauging the extent of the threat posed by maritime terrorism lies not only in an assessment of the capabilities and motivations of the terrorist groups themselves, but also in an understanding of the maritime environment, shipping practices, the vulnerabilities of the commercial shipping industry and the response capabilities of those agencies tasked with safeguarding the region’s shipping lanes. Uninformed claims regarding potential maritime terrorist scenarios, which are based on a misunderstanding or a complete lack of knowledge of these key factors, has led to a misinterpretation of the threat from maritime terrorism. This must be rectified if there is to be any hope of reducing the threat.