THE STRAIT OF MALACCA: A PASSAGEWAY OF INTERNATIONAL CONCERN

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP08C01297R000300080001-2
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 6
• Document Creation Date: December 22, 2016
• Document Release Date: September 12, 2012
• Sequence Number: 1
• Publication Date: April 1, 1971
• Content Type: MEMO

25X1
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DIRECTORATE OF
OF
INTELLIGENCE
Intelligence Memorandum
The Strait of Malacca: A Passageway of International Concern
April 1971
CIA/Bel GM 71-4
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THE STRAIT OF MALACCA:
A Passageway of International Concern
The worlds maritime commerce generally moves along
well-defined routes, many of which converge upon criti-
cal areas of restricted passage such as the Panama Canal,
the Strait of Gibraltar, and the Sues Canal. Often these
passageways are essentially traffic choke points, either
because of maritime congestion or. at times, because of
physical impediments. The Strait of Malacca is such a
passageway.
Lying between Sumatra end the Malay Peninsula, and
consequently protected from both strong winds and rough
seas, the Strait of Malacca Is the shortest and most direct
maritime route from the northern Indian Ocean to the
South China Sea and the Pacific. Historically it has ac-
commodated all classes of ships, but certain shallow
sectors are now being viewed with increasing concern
by business and government leaders in Southeast Asia
and japan. These sectors barely permit the passage of the
present generation of 63-foot-draft tankers, and should
they not be improved, they will be entirely inadequate
for the 85-foot-draft tankers of the futurc,
Thty ourmarenthins toat mewed be the Office al Bodo and
Geographic Intelligence and coordinated within CIA.
Still, the substantial international importance of the
Strait of Malacca--economically, politically and mili-
tarily?makes its unimpeded and uninterrupted use by
all nations almost Imperative. Consequently, international
cooperative efforts have been made to survey the waters
of this passageway in order to improve navigational
safety, to delimit territorial sea and continental shelf
boundaries, and to consider the construction of a petro-
leum pipeline across the Kra Isthmus.
HISTORICAL DEVELOPMENT OF THE
STRAIT TRADE ROUTE
Recognition of the value of the strait as a direct con-
nection between the Indian Ocean and the South China
Sea probably first occurred about 650 B.C., following
Indian explorations into the Indonesian Archipelago. It
was not until about the 4th century A.D., however, that
the strait began to attract constant commercial use as a
favored passageway for maritime trade between India
and Chinn. As trading activities expanded to include
much of the Indonesian Archipelago, the northwest.
Secret
southeast orientation of the strait enhanced its value.
With its southeast end opening almost directly into the
seas of the archipelago, the strait represented the most
direct route between the Indonesian islands and ports
of call to the west, particularly those along the Indian
and Arabian Peninsulas.
The strategic significance of the Strait of Malacca
became Increasingly apparent, beginning in the 16th
century, as European nations expanded their holdings
and developed their rivalries throughout the Far East
Control of the strait was a constant concern of the
colonial powers, and their anxiety in this sphere led to
the founding and development of Singapore, whose
growth as the entripot port of Southeast Asia, in turn,
encouraged greater use of the strait.
The opening of the Soca Canal in 1809 also encouraged
merchant vessels to use the strait, as it then became a
segment of the most direct route between the Far East
and Europe. Prior to this time ships moving between
these areas were required to make the long nip around
the Cape of Good Hopm to do so they usually departed
Irons Southeast Asia via the Lombok or Sunda Straits,
avoiding the Strait of Malacca because it was out of the
way and oriented in the 'wrong" direction.
The soaring East Asian demand for Persian Gulf oil
during the last 2 decades has added a new dimension
to the importance of the strait; nearly every barrel con-
sumed is delivered via the Strait of Malacca. The strait
is especially critical for Japan, which imports 90 percent
of its 3.8 million barrel daily oil requirement through
this passageway. In July 1968, Japanese shipping, ship-
building, and oil interests created a privately financed
Malacca Straits Council in Tokyo to study ways to en-
Sere safe navigation in the strait. The council has sought
permission to construct 30 lighthouses, beacons, and
buoys along the strait.
The importance of the strait as a commercial cor-
ridor is reflected in the number of ships transiting the
waterway. In 1968, an average of 900 oceangoing mer-
chant ships passed through the strait each month. Dur-
ing this time the heaviest users were the UK, which
averaged 163 ships monthly; Liberia had 100, Japan raul
Norway 30 each, and the Netherlands and West Germany
60 each.
PHYSICAL CHARACTERISTICS
OF THE STRAIT
The Strait of Malacca is a 500.mile-tong, funnel.
shaped, and shallow body of water (see Map 500272).
In the extreme northwest, where it opens into the Anda-
man Sea of the Indian Ocean, it has a maximum breadth
of about 220 miles. It tapers toward the southeast, and
in the vicinity of Singapore, it constricts to a minimum
width of approximately 3 miles; this end of the strait
is cluttered with many small islands.
Lying between Sumatra and Malaysia, the strait is pro-
tected from adverse winds, currents, and heavy seas.
Visibility is generally good throughout the year, being
only slightly reduced during short periods in summer
when squalls, locally called Sumatra', sweep into the
strait from the direction of Sumatra.
On the basis of depth, the strait can be divided at
100?50'E into two sections of unequal length. Nearly
the entire northwestern section is deep enough to ac-
commodate any ship now afloat, including the largest
supertankers. Even the mammoth tnnkers now being
designed will be able to navigate this portion of the
Malacca Strait without fear of running aground, as depths
range from approximately 123 feet to 250 feet
The southeastern section, in contrast, is characterized
by sludlow waters and narrow shipping channels. Two
areas within it are especially critic& At applcodmately
2155'N 100557E the channel narrows to a width of only
miles and the water is only 84 to 90 feet deep. The
second critical area lies southeastward from this point
near the Singapore entrance to the strait at appracimately
103?30'E. Waters here are equally shallow, and
the main shipping channel is even more constricted,
being only about 4 mi/es wide. Nevestbehers, with precise
navigation, existing supertankers can still pass through
both meas. If they are not &edged and deepened, how-
ever, mammoth tankers of the future will not be able
to use this section of the strait (See Map 50:1273).
The strait is subject to sedimentation along its entire
length. Deposits are extensive, and they severely limit
the number of channels that are available to modern
shipping, particularly in the extreme southeast Con-
tributing to the accumulation of sediments in the Strait
are the mangrove stands that develop upon any bank
or spit; these stands grow rapidly and they, in turn,
hasten the deposition and accumulation of sediments by
hindering the scouring normally associated with wave
action. Although tidal ranges in the Strait of Malacca
vary from 4 to 13 feet, the average tides am only about
Sleet, and like the prevailing currents that are of tidal
origin, do not have sufficient velocity to be effective
scouring agents. The flood tidal current which flows
from northwest to southeast averages approximately 2
knots, while the ebb tidal current, flowing in the op-
posite direction, averages approximately 2.5 knots.
Heavy discharge of silt-laden waters from Sumatra
has led to a partial filling of the southeastern half of
the strait, and as a result, shallow waters extend from
the island's shores far into the strait, in some locations
as much as 25 miles. Consequently, the main shipping
channel in the southeast is close to the Malaysian shore.
Sedimentation is also increased because Surmise shields
the strait from the strong wave action of the Indian
Ocean.
A peculiar tidal influence contributes to particularly
rapid sedimentation of the southeastern end of the strait
Indian Ocean tides moving from the west dawn the
funnel-shaped strait toward Singapore carry sediment
eastward. These tides are met by others originating in
the South China Sea and the Java Sea. As these tides
converge jest to the south of Singapore, their scouring ?
capacity is reduced, thus promoting a heavy deposition
of suspended materials derived from the adjoining land.
masses.
In consequence of the interactions of currents, tides,
and heavily charged surface runoff, the topography of
the bottom exhibits great irregularity. Channel banks with
eo to 120 feet of local relief parallel the main channeL
Sand waves, with crest-to-trough heights of 12 to 18 feet,
also parallel the long axis of the strait. Most of the hot.
tom material is not solid; mud and sand are predominant,
with large areas of the former occurring near stream
mouths. Limited areas of solid bottom materials, com-
posed primarily of coral, are located in the rather shallow
writers immediately south of Singapore. Except in these
coral arms, dredging operations to deepen selected por-
tions of the channel would not be difficult, in view of the
rather 'soft" nature of most of the bottom.
VULNERABILITY
The Strait of Malacca is vulnerable to blockage by
either natural causes or deliberate interdictory action.
Closure of it, however, would have less of an impact
on the world than the blockage of the Sum Canal, but
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500275 471
ALTERNATE ROUTES
Existing Passages
The Sunda Strait and the Lombok Strait, located about
70 and 10? south of Singapore, respectively, offer alter-
nate passages into the Indian Ocean. Utilization of either
of them, however, would add appreciably to the average
length of voyage. This, in turn, would increase the op-
erational costs? of shipping companies and reduce the
number of round trips that could be made in a given
period of time; to the military, the cost of using to alter-
native passage is measured primarily by the additional
time required to deploy fleet elements from one ocean
Is, another.
The Sunda Strait, between Sumatra and Java, is If
miles wide and has a limiting depth of 162 feet; it is
divided by a small island into two channels, 4 and 51/2
miles wide, respectively. The Lombok Strait, between
Bali and Lombok, has a minimum channel width of
514 miles and a minimum depth of 1.110 feet. The use
of the Lombok Strait by mammoth tankers carrying
Persian Calf oil to Japanese ports would add 3 days
and another 1,000 ;Ironical miles to the voyage; if the
Sunda Strait were used, about 2 days and an additional
700 miles would be required.
The vulnerability of the Strait of Malacca has fostered
a wide range of contingency plans concerning the bypass
of these potentially troublesome waters. The most widely
dismissed proposal is one that would create another
passage across Thailand's Km isthmus. This concept is
not new; the British and French surveyed the area for
this purpose in the latter part of the 19th century. The
'Store than $30,000 par day en 200.00040n tankers.
Japanese also proposed the construction of such a canal
prior to World War II, and during that war, when their
form were dominant in the region, they seriously con-
sidered building it. The necessary detailed engineering
design and cost studies have never been completed,
however, and other than as a sporadic issue in domestic
Thai polities, this alternative to the Strait of Malacca
has not been given much attention in recent years.
Proposed Pipeline
Japan's roaring dependency on Persian Cuff Oil in
recent years has rekindled her interest in finding an
economical alternative to the Strait of Malacca. Out of
this revitalized interest a new and less expensive plan,
involving an oil pipeline, has evolved. This proposed
pipeline, 94 miles long, would cross the southern part
of peninsular Thailand, extending overland from a point
near Phuket Island on the west coast to Surat Thant
on the east coast (see Diagram 510790). The 500,000'
ton tankers, now being designed in Japan, would operate
exclusively in the deeper waters of the Indian Ocean, and
the existing fleet of smaller tankers would transport the
oil from the terminus of the pipeline on the Gulf of
Thailand to Japan. A Japanese study of the project was
initiated about 2 years ago, and it is believed that the
project could be completed in 3 or 4 years. given the
approval of the Thai Government.
INTERNATIONAL COOPERATION
An unprecedented high level of international coopera.
tion is being directed toward the improvement of the
Strait of Malacca as a shipping route. A four-nation
(Indonesia, Japan, Malaysia, and Singapore) preliminary
hydrographic survey, undertaken in January 1969, re-
vealNI that five areas in the strait are so shallow that
they "would not be safe for giant tankers over 200,000
tons to pass through the straits at all stages of tides
and night." This discovery led the same nations in the
summer of 1970 to agree to carry out a full-scale hydro-
graphic survey of the strait. Whereas all of these coun-
tries are contributing something to this joint undertaking.
Japan and Indonesia ore assuming a major port of the
responsibility. The former Is financing the survey and
providing advanced technology, and the latter is furnish-
ing the survey ships. All stand to benefit, however,
should the survey lend to improvements that would as-
sure the continuance of the strait as an avenue of com-
merce. This is, of course, the basic aim of Japan as well
as that of the adjoining coastal states, each of which
recognizes the benefits to be gained by the elimination
or reduction of navigational hazards in the more restricted
channels. In addition, the risks of pollution and the pos-
sible destruction of marine life, resulting from oil tanker
spillage or collision, could be minimized.
The United Kingdom is also working in the straits.
Their hydrographic ship Hydra is conducting a survey,
presumably to provide information deemed essential for
the implementation of British defense obligations. The
Hydra survey, reportedly assigned in cooperation with
Japanese-led surveying operations, is expected to be
completed by April 1971.
Nations of the area, in an attempt to harmoniously
develop the entire region, signed the Hist Asian con-
tinental shelf boundary (CSB) agreement in October
1969. In this accord, undertaken voluntarily and achieved
through mutual concessions, the governments of 2dalaysa
and Indonesia demarcated the CSB in the Stroll of
Malacca and the South China Sea, A few months later
they reached substantial agreement on territorial waters
in the Strait of Malacca. This was another significant
achievement, as both nations had claimed a 12-rnfle ter-
ritorial sea, thus provoking overlapping claims in those
places where the strait is less than 24 miles wide. The
territorial water bormdaries agreed upon are identical
with the CSB except for a very small area between
boundary points 5,6. and 7. (See Map 500271).
Relatively minor, but mutual, =cessions have been
made to reach these regional accords. In fear of external
national and commercial interrats becoming dominant
In the strait, however, nations of the region may con-
sider the creation of a littoral states strait commission.
Legitimate concern about the environment. as well as
the obvious commercial benefits brought by strait traffic,
provides an extra measure of impetus for the creation of
a regional organization that would coordinate develop-
ment and pnwide for the control of this strategic inter-
national watenvay.
OUTLOOK
The ever-increasing economic Interdependence of
world regions indicates that the tonnage of commodities
transiting the strait to and from Asian commercial centers
will increase. Forecasting his nation's future, Prime Min-
ister Lee Kuan Yew of Singapore recently said, "As long
as the balance of geopolitical forces in South, Southeast,
and East Asia remain as they are, then Singapore's stra-
tegic value will remain undiminished." His statement
appears equally valid for the entire Strait of Malacca area.
Although the British military presence in the strait area
has been reduced, this policy reflects domestic retrench-
ment rather than a strategic reassessment of the area.
Japan, China, Australia, and to a lesser extent, the United
Stater and the Soviet Union also have irrdividiral con-
cerns for the area. None, however, at least for the present.
seem compelled to fill the "vacuum" created by the with-
drawal of all but token British forces. Even if sufficiently
motivated, it is unlikely that any single foreign power.
could achieve political predominance over the nations
adjoining the Strait of Malacca in this era of rising
nationalism among the developing nations.
Construction of a canal across the Kra Isthmus appears
economically Infeasible and tmnecessary as the majority
of the world's cargo ships, now in use and planned, will
not require channel depths that are greater than those
in the Strait of Malacca. The proposed pipeline, how-
ever, may well be constructed. It would permit the use
of 500,000-ton Japanese tankers in the deeper waters of
the Indian Ocean and on other deep-water routes and
facilitate that nation's effort to tap a wider range of
petroleum sources.
Proposed Kra Isthmus Pipeline
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