AN EVALUATION OF THE HARBORS OF SUBIC BAY AND MANILA, REPUBLIC OF THE PHILIPPINES, AS TYPHOON HAVENS
John AT len Douglass Library Naval Postgraduate Scnooi Monterey, California 93940 VAL POSTGRADUATE SCHOOL
Monterey, California
THESIS
An Evaluation of the Harbors of Subic Bay and Manila, Republic of the Philippines, as Typhoon Havens
by
John Allen Douglass
September 1974
Thesis Advisor G . J . Haiti ner
Approved for public release; distribution unlimited.
116
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4. TITLE (and Subline) 5. TYPE OF REPORT » PERIOD COVERED
Master ' s Thesi s An Evaluation of the Harbors of Subic Bay September 1974 and Manila, Republic of the Philippines, 6. PERFORMING ORG. REPORT NUMBER as Typhoon Havens 7. AUTHOR(«J 8. CONTRACT OR GRANT NUMBERfsJ
John Allen Douglass
9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT. TASK AREA 4 WORK UNIT NUMBERS Naval Postgraduate School Monterey, California 93940
II. CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE Naval Postgraduate School September 1974 Monterey, California 93940 13. NUMBER OF PAGES 111 14. MONITORING AGENCY NAME 4 ADDRESSf// dllterenl Irom Controlling Olllce) IS. SECURITY CLASS, (ol this report) Naval Postgraduate School Monterey, California 93940 UNCLASSIFIED 15«. DECLASSIFI CATION/ DOWN GRADING SCHEDULE
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18. SUPPLEMENTARY NOTES
19. KEY WORDS (Continue on reverse elde It neceeaery and Identity by block number) Tropical cyclone Typhoon Typhoon Haven
Mani 1 a S nhi c Ray 20. ABSTRACT (Continue on reveree tide It neceeaery and Identify by block number)
This study evaluates the harbo_r_s„j)f_Subi c. Bay and Manila as possible typhoon havens. Characteristics of the harbors under tropical cyclone conditions, including climatology, topographical effects on the wind, and reliability of moorings and anchorages at each harbor are discussed. Problem areas to be considered if remaining in port and suggested evasion procedures for ships sailing fro m the p ort are examined. The
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20. (continued)
tracks of tropical cyclones from 1884-1973 for the western North Pacific were analyzed to assess the threat posed to each harbor by a tropical cyclone. Results suggest that neither port is an entirely safe haven. Subic Bay could be a haven under certain specified conditions while Manila should never be considered a typhoon haven. To aid commanding officers, operationally oriented flow diagrams are presented which summarize the locations of the various sections of the text that could be used in decision making.
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1
An Evaluation of the Harbors of Subic Bay and Manila, Republic of the Philippines, as Typhoon Havens
by
John Al en / Douglass Lieutenant Commander, 'United States Navy B.A., Gettysburg College, 1965
Submitted in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE IN METEOROLOGY
from the
NAVAL POSTGRADUATE SCHOOL September 1974 96 Library Naval Postgraduate School Monterey, California 93940
ACKNOWLEDGMENTS
The author wishes to acknowledge the contributions of the following individuals of the Environmental Prediction Research Facility: Mr. S. Brand for his helpful suggestions and guidance throughout the writing effort, Mr. J.W. Blelloch for his help in compiling and reducing data, Mr. R. Clark for his graphical assistance, and Mrs. W. Carlisle for her expert typing of the final manuscript. LT B.B. Edwards, Naval Weather Service Environmental Detachment, Naval Air Station, Cubi Point, R.P., is acknowledged for his invaluable assistance in the data compilation phase of this study... _ .In addition, the assistance of the Naval Weather Service Detachment, Asheville in providing data is gratefully acknowl edged. The guidance and assistance received under the direction of my thesis advisor, Dr. G.J. Haltiner, Chairman, Department of Meteorology, Naval Postgraduate School, (NPS), is gratefully acknowledged. Professor R.J. Renard, MPS, and CDR J.D. Jarrell , USN, are also thanked for their comments and critique.
TABLE OF CONTENTS
ACKNOWLEDGMENTS 1
1. INTRODUCTION 5
.1.1 BACKGROUND 5 ~ 1.2 THE MEASURE OF A HARBOR . 6
2. TROPICAL CYCLONES .'.... 7
2.1 DEFINITION AND CLASSIFICATION 7 2.2 DEVELOPMENT 7 2.3 MOVEMENT 8 2.4 WIND CIRCULATION AND INTENSITY 9
2.5 SEA STATE . . . 9
3. THE PHILIPPINE ISLANDS IN RELATION TO TROPICAL CYCLONES 14
3.1 GEOGRAPHICAL LOCATION 14 3.2 EFFECT OF PHILIPPINE ISLANDS ON TROPICAL CYCLONES 14
4. SUBIC BAY 19
4.1 GEOGRAPHICAL LOCATION 19 4.2 TOPOGRAPHY 19 4.3 PORT OLONGAPO COMPLEX 19 4.4 HARBOR FACILITIES 22
5. TROPICAL CYCLONES AFFECTING SUBIC BAY 23
5.1 CLIMATOLOGY 23 5.2 WIND AMD TOPOGRAPHICAL EFFECTS 34 5.3 WAVE ACTION 47
5.4 | STORM SURGE AND TIDES] 47
6. PREPARATION FOR HEAVY WEATHER 48
6.1 TROPICAL CYCLONE WARNINCS 48 6.2 REMAINING IN PORT 48 6.3 EVASION 50
7. CONCLUSION (SUBIC BAY) 54
DECISION FLOW DIAGRAM - SUBIC BAY 56
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8. MANILA 57
8.1 GEOGRAPHICAL LOCATION AND GENERAL DESCRIPTION . . 57 8.2 TOPOGRAPHY 57 8.3 MANILA HARBOR 57 8.4 HARBOR FACILITIES 61
9. TROPICAL CYCLONES AFFECTING MANILA 62
9.1 CLIMATOLOGY ". 62
'. 9.2 WIND AND TOPOGRAPHICAL EFFECTS . . . 62 9.3 WAVE ACTION 63
10. PREPARATION FOR HEAVY WEATHER 68
10.1 TROPICAL CYCLONE WARNINGS 68 10.2 REMAINING IN PORT 68
10.3 EVASION . 70
11. CONCLUSION (MANILA) 74
DECISION FLOW DIAGRAM - MANILA 75
REFERENCES 76
APPENDIX A - MONTHLY STORM TRACKS FOR YEARS 1946-1969 ... 78 APPENDIX B - MANILA (SOUTH HARBOR) HARBOR FACILITIES ... 90
APPENDIX C - SUBIC BAY (PORT OLONGAPO) HARBOR FACILITIES . 92 APPENDIX D -"HEAVY WEATHER PLAN FROM COMNAVPHIL OPORD NO. 201-72 94 APPENDIX E - SHIPS SPEED VS WIND AND SEA STATE CHARTS ... 97 APPENDIX F - CASE STUDY OF TYPHOON IRMA (MAY 11-20, 1966) .101
INITIAL DISTRIBUTION LIST Ill
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1. INTRODUCTION
1.1 BACKGROUND
The tropical cyclone, and in particular the typhoon, presents one of the most awesome and difficult problems to all Fleet units in the western North Pacific Ocean (WESTPAC). In recent years, the accuracy of forecasting typhoon direction and speed of movement has vastly increased. However, this increase in accuracy has not reached the level of eliminating a basic decision by commanders of Fleet units; namely, when faced with a typhoon threat whether to seek or remain in the shelter of a harbor or to take evasive action and ride out the storm at seaT For most WESTPAC harbors there are insufficient or inadequate data available to the Fleet unit commander upon which to base a truly knowledgeable decision. Previous studies on the harbors of Hong Kong (Mautner and Brand, 1973) and Kaohsiung and Chi lung (Keelung) in Taiwan (Brown, 1974) have been completed and should provide much information about these harbors. This study examines the harbors of Subic Bay and Manila in the Philippine Islands as possible "Typhoon
" Havens . The multitude of variables involved make it practically impossible to classify a certain harbor as "safe" or "unsafe."
This study will examine meteorological, oceanographi c , topo- graphical, and individual port characteri sti cs i n an effort to evaluate the harbors of Subic Bay and Manila as typhoon havens. However, there are other less tangible factors which must be considered, such as, for example, those included in the overall
"measure of a harbor."
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,
1.2 THE MEASURE OF A HARBOR
"The measure of a harbor is the sum total of
many individual factors . It is in the extent of
its shelter 3 depth of water at the piers, quantity and condition of its service craft and the efficiency
of its port services . It is measured by the experience
level of its port services officer. It is 'in the skilly spirit and will of his crews. It is in the emergency capability of the Ship Repair Facility to make a ship ready for sea. It is the quality of the typhoon warning service and the lead time provided the Senior Officer Present Afloat (SOPA) to make sound command decisions and to the Port Services Officer to carry out smoothly and efficiently his flexible plan of action. Finally the measure of a harbor is knowledge of that harbor and all that it connotes in the mind of the Senior Officer
Present Afloat who, by his decisions , will stamp it as a vital refuge to be taken or as an inanimate limited
shelter to refuse as a. harbor for the ships under his charge." (U.S. Fleet Weather Facility, Yokosuka, Japan,
1967. )
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2. TROPICAL CYCLONES
2.1 DEFINITION AND CLASSIFICATION
A tropical cyclone is a low pressure disturbance whose central core is considerably warmer than the surroundings up to wery high levels. It is differentiated from mid-latitude
(extratropi cal ) , cold-core cyclones by its origin, dynamics, and the meteorological characteristics of the air masses involved. Like typical low pressure systems, the wind circu- lation in a tropical cyclone is counterclockwise about its center in the Northern Hemisphere and clockwise in the Southern Hemisphere. By joi nt~ international agreement, tropical cyclones in the WESTPAC area are classified according to their intensity as follows:
Tropical Depression - maximum sustained winds not exceeding 33 kt
Tropical Storm - maximum sustained winds between 34 and 63 kt
Typhoon - maximum sustained winds 64 kt or greater
2.2 DEVELOPMENT
The primary region of tropical cyclone development lies between latitude 25N and 25S, except very near the equator.
The area between the latitudes 5N to 20N and from 1 70 E longi- tude to the Philippine Islands produces more severe tropical storms than any region in the world. It is in this area that the water temperature is always above 26°C (78.8°F). Empirical data indicates that warm water such as this is a necessary condition for the development and intensification of tropical cyclones. These warm ocean waters over which the tropical cyclones travel provide the energy required for the growth and sustenance of the storm (Palmen and Newton, 1969).
.
2.3 MOVEMENT
Considering the WESTPAC region as a whole, the majority of typhoons conform to the usual tropical cyclone track pattern and move initially westward or west northwestward from the source region. Those that reach higher latitudes, normally north of 20N, have a tendency to recurve and even- tually move in a northeasterly direction over or to the east of Japan. However, a considerable number of typhoons travel almost due westward, cross over the Philippines, and eventually dissipate over China or Southeast Asia. Prior to recurvature, most tropical cyclones move at speeds ranging from 8-12 kt. After recurvature, this speed of movement can accelerate within 48 hours to as much as 2-3 times the speed at the point of recurvature (Burroughs and Brand, 1972). The course of individual storms cannot be said to follow any such standardized patterns. Numerous typhoons have followed extremely erratic courses, even making occasional loops in their tracks. For this reason the progress of each typhoon should be closely monitored for changes in intensity and direction and speed of movement.
See Appendix A for monthly cl imatol ogi cal tracks of tropical cyclones in WESTPAC which at some time were of typhoon i ntens i ty
2 Recurvature - The westward progression of a tropical cyclone ceases and a northerly and finally northeasterly course results. Approximately 40% of WESTPAC tropical cyclones recurve.
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2.4 WIND CIRCULATION AND INTENSITY
The wind systems of tropical cyclones vary greatly in
size, from as little as 100 n mi in diameter to 1000 n mi or more. The shape of the wind system is more or less circular. At the periphery the winds are light, but they increase inward
toward the center of the storm. Figure 1 depicts the wind
pattern around a typical large, intense typhoon.- Note that the winds in the right semicircle of the circulation are more
intense. For this reason the right side of a tropical cyclone is known as the "dangerous semicircle."
There is a pronounced gustiness of the winds, even at the periphery; nearer the center the more violent winds occur in
heavy squalls. In the center of a mature typhoon there is a region of calm or light winds, known as the "eye," which is surrounded by the strongest winds of the entire storm system.
2.5 SEA STATE
The appearance of sea swell is often the first and one of
the most dependable precursors of the approach of a tropical cyclone. The rate of movement of these swells is usually 30 kt or more, so they rapidly outrun the storm field and are often observed many hundreds of miles in advance of the storm circulation. 3 Figure 2 shows the combined sea height associated with 21 tropical storms and typhoons (based on 173 analyses for the year 1971) plotted as a function of distance from the tropical
The combined sea height is defined as the square root of the sum of the squares of "significant" sea and swell height. Sea represents wind waves and swell consists of wind generated waves which have advanced into regions of weaker or calm winds. "Significant" will be defined here as the average height of the highest one-third of the waves observed over a specified time.
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•
FT ymm^ mmsmmmmmmmmiKmmfmmimfmtmmmmmm!mmmtm
2 2 DEGREES OF LONGITUDE
Figure 1. Distribution of surface wind speed (in knots) around a large, intense typhoon in the Northern Hemisphere over open water. The arrow indicates arbitrary direction of movement (after Harding and Kotsch, 1965)
10 -
.
Q> C O rHo—• >,m O r> CT» rHiH ctf O - •H • Q4-H O (01 H -P -P nj cti / 0) U) 10 rt n3 CJ a C (1) •H > UtJ G ftf CM U 0) CD P H C d 0) (Jj) 1H3I3H V3S 03NI3W03 tPO -H fu -II- cyclone center and tropical cyclone intensity. The large variation in the sea state with tropical cyclone intensity is quite evident. The distances indicated are mean distances since the isopleths of combined sea height are not symmetric about the storm center. Figure 3 shows the average combined 9-15 ft sea height isopleths for tropical cyclones moving between 240° and 360°. It is based on 81 sea state analyses between 240°-300° and 66 analyses between 301°-360°. These analyses were for tropical cyclones that occurred during 1971. Notice that the greatest area of higher seas (9-15 ft range) exists to the rear and toward the right semicircle of the tropical cyclone. It should be noted that, Figure 3 is applicable only to the WESTPAC area east of the Philippine Islands. Figures for the South China Sea are approximately 20% less than those for the above area (Brand, et aj_. , 1973). 2 - 400 < 400 (9-15 for Figure 3. Combined sea-height isopleths ft) \ tropical cyclones heading between 240°-360° (after Brand, \ et al. , 1973) ... » 3. THE PHILIPPINE ISLANDS IN RELATION TO TROPICAL CYCLONES 3.1 GEOGRAPHICAL LOCATION Figure 4 shows the geographical location of the Philippine Islands in the western North Pacific Ocean. The Philippines constitute the largest island group, in terms of numbers, of the Malay Archipelago. They consist of approximately 7100 islands and islets, of which Luzon is the largest, covering an area of approximately 115,600 square miles. 3.2 EFFECT OF PHILIPPINE ISLANDS ON TROPICAL CYCLONES The degree of land influence on a tropical cyclone is a function of the area and topography over which the storm is passing. Figure 5 depicts the topography of the Philippine Islands. It can be seen that the terrain of the Philippine Islands varies a great deal, ranging from extensive mountainous regions on Luzon and Mindanao to a sea-land mix in the central Philippine Islands. Brand and Blelloch (1972) showed that the intensity, speed, and circulation size of typhoons are greatly influenced by the Philippine Islands. Two of these parameter changes are depicted in Figures 6a and 6b. The typhoons used in this study were divided into two categories: intense typhoons, or those having an initial average intensity _>90 kt in the 24- hr period prior to crossing the Philippines, and weak typhoons, or those having an average initial intensity £90 kt in the 24-hr period prior to crossing the Philippines. The intensity of intense typhoons decreased 45-50 percent in maximum sustained wind while the weak typhoons only decreased in intensity 10-15 percent. The speed of intense typhoons shows little decrease, 14 o u o •n g O o w c o •H r, u. < •H S; — u* o u u CO z < o O& -P CO c O o c a ^> o o o o •H ^±1 IM 7£?=? •H C ui O z ta a> x: +j 5-1 O >-i Q) -P U) 0) £ o -p m o cu • rt W S ° in 1 en | • «S M* e Q) 'd! u « 2 (0 tP-H -H fe - 15 - . I—WW i wmmmmm o If / -20°-* PHILIPPINE SEA SUBIC BAY , -15°- SOUTH CHIH/L.. SEA MANILA -i ! -10°- t&MINDAMAO ' '«« mihwww mis. - 16 - . a +24 +12 -12 -24 -36 AFTER CROSSING (Hours BEFORE CROSSING speed (b) profiles for Figure 6. Average intensity (a) and ( intense and weak typhoons crossing the Philippines (Brand I and Blelloch, 1972) - 17 while weaker typhoons, which move faster, show a marked decrease in speed (see Figure 6b). The circulation size of all typhoons considered decreased on an average of 17% in area! extent when crossing the Philippines. - 18 4. SUBIC BAY 4.1 GEOGRAPHICAL LOCATION Figures 5 and 7 depict the geographical location of Subic Bay on the island of Luzon. Subic Bay, centered near 14°50'N and 120°14'E, is approximately 4 n mi wide and 9 n mi long. The entrance to Subic Bay opens seaward to the Southwest and Grande Island, located in the mouth of the bay, divides the entrance into two channels. The main channel, lying to the west of Grande Island is wide, deep, and clear of obstructions. 4.2 TOPOGRAPHY Figure 7 depicts the topography of the terrain surrounding Subic Bay. The bay is surrounded by mountainous terrain in all directions except south-southwest. Peaks in excess of 4000 ft lie to the northeast with passes through the mountains to the east-northeast. Figure 7 also depicts the bottom topography of Subic Bay. Depths in Subic Bay decrease regularly from 200 ft in the entrance to 50 ft at its head. The greater part of the bay, including the Port Olongapo complex, has been swept to a depth of 49 ft. The entrance channel across Subic Bay and into the Port Olongapo complex is approximately 850 yards wide and has generally decreasing depths of 180 to 72 ft. 4.3 PORT OLONGAPO COMPLEX Port Olongapo consists of an outer harbor and an inner basin (see Figure 8). The port complex is approximately 1 1/2 miles wide between Cubi Point and Kalaklan Point and extends about 1 1/2 miles eastward to the coast. The inner basin lies between Maritan Point and Rivera Point, with the NSD terminal pier extending from its northeast shore. The shore is - 19 i*WW***JJ»'Wy*,*^^S','!*.Afc3t/WWB**Aifl6MriHWW 20 o u x: o •H > u (d c: to o •H ft O o •H +> <1) +J £ to O ft w ,c to o ft >i rt > tn rd O .h • O c/3 P D O O G) a o 5-1 to to tn (d - 21 extremely steep v/ith liitle shoaling effect extending beyond a quarter mile offshore. Since Subic Bay is a U. S. Navy installation, all facilities are available for assignment to U. S. Navy vessels. 4.4 HARBOR FACILITIES There are 6 wharves and 2 piers which serve' as primary berthing spaces for vessels entering the Port Olongapo complex Appendix C gives individual wharf and pier characteristics and facilities available. There are also 13 supplementary berths which are used for small craft only. There are more than 160 safe anchorages in water depths of 70 to 150 ft with soft mud or coral bottom available in Subic Bay. Mooring buoys for all sizes of ships are available and assigned by the Port Operations Officer (H.O. Pub. No. 918, 1974). - 22 5. TROPICAL CYCLONES AFFECTING SUBIC BAY 5.1 CLIMATOLOGY Due to the extremely close proximity of Subic Bay to Manila Harbor, the two ports will not be considered separately with respect to the climatology of tropical cyclones. For the purposes of this study, the mid point (labeled point X in Figure 11) of a line connecting Manila Harbor and Port Olongapo was used. Point X is the center of a 180 n mi circle used to determine whether or not a tropical cyclone represents a threat (any tropical cyclone approaching within 180 n mi of point X is considered a threat) to the ports of Manila and Subic Bay. It is recognized that a few storms which did not approach within 180 n mi may have affected either or both ports. How- ever, a reasonable criterion had to be chosen that would limit the size of the data sample. Although tropical cyclones can occur at any time of the year, the majority of those that threaten Subic Bay and Manila occur during the months of June through December. Figure 9 depicts the monthly summary by 5-day periods of tropical cyclone occurrences based on data for the 19 years, 1955-1973. Of the 83 tropical cyclones that threatened Subic Bay and Manila, the peak threat periods exist in July, October, and November, but a consistent threat exists throughout the total June-December period. Figure 10 displays the above storms as a function of the compass octant from which they approached point X. The numbers indicate the number of storms approaching from that octant, while the numbers in parentheses indicate the percentage of storms approaching point X from that octant. It is evident that the majority of storms approach Subic Bay and Manila from the east-southeast. 23 - — H——— BB r — ',lilte'wi-»i»» WlifiW kl**i. iV-l I \ L5J T3 rt O O CO -H fd O O, M -P t -P r3 M £ O > -P 4-1 i .'.' W - t w t / o c; ra Z o o i-f -H - ..- • B . - < o M u a, C28" I r^r^r.-a-*,. ; ' ~|>^e^ , ^}A~$r_ .#1 < U P T3 (2 P G •HOG U 3 O O o u o 3 "3 g p o c r3 1" CO r-i V} O en C G •H O uHLAXi^ii^i. m p o 2 -.H >i •H in S3NOTDAD TVDIdOMi iO MaawflN - 24 - 4-> c +J o £ rj •H -H O *-*. +>x! m O -P y CO ^-^ 0) -H n & u H m C) QT rH o 'd a in 0) h • W £1 d o m u to .-! (id o r-\ 0) 4-> u a u rj cu± 3 x: CU CT>4-> (d -U -.H fM - 25 An overall statistical summary of the tropical cyclone climatology of Subic Bay and Manila for the years 1884-1970 is provided by Figures 11 to 17 (based on data from Chin, 1972). This summary is based on tropical cyclone tracks grouped by months, June through December. Exact calendar months could not be used because the tracks were recorded for 5-day periods. To accurately assess the threat to Manila and Subic Bay, the following parameters were used: N - The total number of storms that passed through each 3° lat/long box for a given month, RAD - The percent of those tropical cyclones that passed through the box and passed within 180 ~ n mi of point X, R-. - Percentage of all tropical cyclones that passed through the box and crossed the line north of point X within a distance of 60 n mi (1° latitude), R - Percentage of all tropical cyclones that passed 3 through the box and crossed e line north of point X within a distance of 180 n mi (3° latitude) , L, - Percentage of all tropical cyclones that passed through the box and crossed a line south of point X within a distance of 60 n mi (1° latitude), L~ - Percentage of all tropical cyclones that passed through the box and crossed a line south of point X within a distance of 180 n mi (3° latitude). H and RAD are printed on the top and bottom of the box, respectively. The others are printed at the left and right edges of the box. For example, in Figure 11, the 3° square located between 129E and 132E, 9N and 12N had 8 tropical cyclones pass through it during the years 1884-1970. Of these, 63% approached within 180 n mi of point X, 13% passing within 60 n mi to the south and 25% within 180 n mi to the south; no storms passed within 60 n mi to the north and 25% within 180 n mi to the north. 26 1 ^ "• o o f* CN T- w -p 1 rH 1., O o o o o .=* -* O O o ^ o o o a HC Ch rH CO ro rH o o C- o o -* -* o OJ CM CVJ t-i rH OJ o o o -P c .c o o o o O o o o o o o o o o -H rj +J o O o o o ON on ^ CO O 0- o o o o n IT\ o o o ON 0- O rH VO o o CJ OJ rH C~\ CJ rH o O o to V-i CN o o o o O o o o O o OJ o o 10 . r3 r^ CM o o o o o o C*\ o O O o o o o r-i ft r- cn. 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(U o pa *j e tS *- 1 -3 *J»TJ «j€i^ All - '" • _ >v O • B C B ' 1 U X! ». e i o I \ m « s « » a tana coo -* 1 a c O c O O • CO OO • c — « c s -« •H ! c o ci-c— etc EtiE- to ~~- o o — - o i; -« • Ona; H o o oo-*" ^. i,.^ -P -^ i P a w • C S ~i -J n wax; a 1 ! a m >-3 0«X c c > -5 0«S " * > -H -H O • o O XI u X p <~< K •HMX^ .-*»«XO ^IMX'^ HHrl UJ i xo r^ O JO -« •jo — do rt d o **- t*c P o >.*-- *> — CC4J a 1 O J u£ ^ o>5^)— c^iC td a, vj en o -. sz«-< c: -< t:«-*--' \\ M P. * — V p o H r-l o *- o • Oh C *< 9 0-*0^< U-*^ t» ^ c O" ** ~"~-. t. Z. -"^ t- r — - U C Z~ ~ U C U~* t- 1Z < — n W 4H 4H 1 ! a j u »: »» *' " «-!•> £ »>•> i -r. x. i • c z: e n « / . o •<=r < CV-« ** z. n f-»i:oz -*co ^irc^ — r rj > «- - 33 - Figures 18 to 24 represent an analyses of the RAD numbers from the above figures. The solid lines represent the "percent threat" for any storm location. The dashed lines represent approximate approach times to point X based on an approach speed of 8-12 kt. For example, in Figure 18, a storm located at 130E and ION has between a 60% and 80% probability of passing within 180 n mi of point X and it will reach point X in approximately 2 1/2 days if its speed remains within 8-12 kt. 5.2 WIND AND TOPOGRAPHICAL EFFECTS In the 19 year period from 1955-1973, during the months June-December, a total of 83 tropical cyclones approached within 180 n mi of Subic Bay, which is more than four tropical 4 cyclones per year. The largest number of tropical cyclones to threaten Subic Bay in any single year was 11 in 1954. Table 1 groups the above 83 tropical cyclones according to the 5 wind intensity that they produced at Subic Bay. Of the 83 tropical cyclones concerned, 36% resulted in strong winds (>22 kt) and only 13% resulted in gale force winds (>34 kt). From Chin (1972) for years 1955-1970 and from Annual Typhoon Reports for years 1971-1973 (U.S. FWC/JTWC, 1971-1973) 5 Wind data are from Naval Air Station, Cubi Point, but are not continuous for years 1955-1957 since wind observations were made only during station operating hours. The data are considered representative of the winds in Subic Bay in most instances. The possibility does exist that winds from the southeast quadrant, due to the surrounding terrain, will indicate a lower velocity at Cubi Point than that experienced in the bay. It should be pointed out that because of the surrounding terrain around the Subic Bay area, it is very difficult to find a recording spot truly representative of the area . - 34 - J i o a, m r3 o •m O to e M p O Id c C) P >i o P CO o 0) -H 1-4 XP C 'C -H c u si id o p IW •H p 5 o ^-> XJ CM ^ P r- 0) (d 35 . - > —' o n, nj «h tn o o •rH H cn o E C Jh id C -P a) M >i o CJ CO ft o rH .a rd + rt ci -H id M x: +J U «r! H o & X! — U - 36 - — ^->. a. rd IH d o G CI O Sh -H rH rd g c O >i g + U o o a .G co Ph p rH a u G c -H r3 UH ,G P H ^^ -H CN £ ,£ r^ H cr\ TJ Rj rH O K w 05 id G rd rH -H cvh x: G u -P rd rd a g .G o P Cn r-l (-" m en •H o p rd G u +1 o o rd •H G T3 O G >i O G o O rH cy i3 as c O u H 05 •rH H rd D. ra o fd * rH •P U- m o p• O -p in G a o •H CT> Cr> O 3 P(0 cu< C T3 m M •H o U 6 M rG o> 0) P cu *G G — P O • e o • r» o X cy cr> CN rG rH P P I GJ G ^ U •rH U co o co CT> &|IH rH •H Cn - 37 -1 o in tr> «3 o >i 33 - » ) ' ' aO uj IH Cn w O C M tf •rH rH e >i c -P O n x: -p CO 04 rH u T3 C C «H •H d x; . -p u CN •H r^- Z J- CTl n rH »-» 39 - o CN O Oi U-t tn U o id B) •H >1 E •p .a n +) o o CO a. u o '3 «H (3 — CM -p O oi .n -H ^ *" w •H w d x: D. •H c e -P id o id ,C -P en d d en •h P i o o U T3 GJ a w id u •H CQ -H rH »-* a. o id M -P m u m o o o g o > tn o o n •p rO M-l o •H O o g u x: o -p a ~ o • e o n r- cs Si H -p I 0) S-l M co O co tn a>^* -h 40 - —* o ft Id to IH tn U O £ id O 0) H rH >. e o QJ G 4J n 6 o O H00 Oh U T3 •*! c C •H id ^-^ 5 CN •H o fl) O •B P< 5 • — no • r» •:J' X a cn CM -p ST Q) r, "3" M rH HCO o O co D> O^ >-H •-H In - 41 - Table 1. Extent to which tropical cyclones affected Subic Bay during the period June-December, 1955-1973. Number of tropical cyclones that passed 83 within 180 n mi of Subic Bay Number of tropical cyclones resulting in 30 strong (>;22 kt) winds at Subic Bay Number of tropical cyclones , resulting in , -, gale force (_>34 kt) winds at Subic Bay It is apparent from the results of Table 1 that Subic Bay is a sheltered harbor. This sheltering effect provided by the terrain surrounding Subic Bay is depicted in Figure 7. The mountains surrounding Subic Bay serve as an effective wind barrier and are the reason that 56 kt is the highest sustained wind recorded there during the years 1955-1973. Figures 25 and 26 depict the tracks for the months June through December of tropical cyclones occurring during the period 1955-1973 that resulted in gale force winds at Subic Bay. From this orientation and a comparison with the percent threat figures in the preceding section, it is evident that tropical cyclones approaching from the southeast and east and passing, in general, to the north represent the primary threat to Subic Bay. The arrows showing tropical cyclone movement in Figure 27 give the positions of tropical cyclone centers when the wind first and last exceeded 22 kt at Subic Bay. Figure 28 shows the position of tropical cyclone centers when the wind first and last exceeded 34 kt. Note that in most cases the tropical cyclones that affected Subic Bay with winds exceeding 22 kt passed to the north. In all instances, the onset of 22 kt winds did not occur until the tropical cyclones had approached within approximately 100 n mi of the eastern coast of the Philippines. On the other hand, tropical cyclones in the South China Sea more than 300 n mi from the west coast of the Philippines have produced 22 kt winds at Subic Bay. Note that - 42 - * u m 0) r- -P 1 >-l in Dim 03 fl t7> O ^ a -p Q) •H i/i & a(d fd — o -p (d • •H -p U) 3 w tt> 10 3 Id < IT (fl « ^ O u id •^ n X) H to . -p in td CS U) (U "0 u C •H tx> 5 Cn - 43 - p e rtf o 0) M Jh l H O rj — 13 (U C o o u O 13 H cq 5 u •H O •H i U U o a w ,q in G RJ QJ JJ [0 P« gj a c CO o rH n o ^ u r-; o H R o o •H.q o ^ in -P O 'H 4-1 O >i a til w a: u o rj -H M ^ Eh 2~ 01 • ro . -P r- VD fd dj T3 m M Cm 3-h - 44 - XJ rt tf +J W Hu m in T3 HC S ^—>. -P ft .* OT r^ CN CT\ CM rH A 1 IT) a in o cr> XI rH & E CO () M n 0) IH +J a rd GJ +> U rd TJ o c C o iH O ^ >i u tn id rH pq id Ho ft • C) >. M rj +j a >H O o •H tn -B fi to O -H -p +J Cj •H 01 m o P-4 u u 3 • U r- O CM o CJ -P m (0 3 id Ui-H •H [-•< 45 xs a rj -P tfl u •H «H Dl r a •H & 4J • .M m r- «tfm HCTl A 1 in C in c> en .£ H ,-i e 10 CJ U U (!) m •P C ra Q) -p U rrj a 01 c, c o H u tj >1 cu n (3 H pq (3 ^-* HO Oj • O >i M id -P m m V r\ CO 3 r; w •H p •P fd •H 10 TJ O 0) Ck n M 3 • o CO u CM o Q) +J U en 3 to C-H •H^ - 46 - most strong wind occurrences exist with storms to the north and west of Subic Bay. 5.3 WAVE ACTION The largest waves in the vicinity of Subic Bay occur just outside the entrance of the bay. Examination of avail- able wave data revealed that southwest monsoonal- wi nds and typhoons in the South China Sea are responsible for the high wave conditions at the entrance to Subic Bay. Another contrib- uting factor is the hydrography in the area, the predominant feature being the relatively deep water close to the entrance of Subic Bay and the reefs along the shorelines (see Figure 7). Although no direct observations have been recorded at Subic Bay, computational estimates (Johnson and Wiegel, 1955) indicate that significant wave heights of 32 ft and periods of 12 seconds could occur at the entrance to Subic Bay with the close passage of an intense typhoon. The interior of Subic Bay is protected from significant wave action by the geography of the area, the southwest orientation of the bay, and the nearby hydrography. Only waves from the southerly or westerly directions have any effect on the interior of Subic Bay. These waves enter the bay, but reach interior points only by refraction around the east or west sides of Grande Island, ana are of little significance. 5.4 STORM SURGE AND TIDES Examination of charts from a now defunct portable tide gage and conversations with engineers revealed no evidence of storm surge in Subic Bay (Johnson and Wiegel, 1955). Tidal currents in Subic Bay are variable and generally weak. Tides are predominantly diurnal, with a tidal range of 3.1 ft (average) and 6.0 ft (extreme). - 47 . 6. PREPARATION FOR HEAVY WEATHER 6.1 TROPICAL CYCLONE WARNINGS Tropical cyclone warnings, including 24-, 48-, and 72-hr forecasts, are supplied by the Fleet Weather Central /Joi nt Typhoon Warning Center (FWC/JTWC) located on Guam. COMSEVENTHFLT OPORD 201-(YR), Annex W, describes the procedures and techniques to be used when plotting the FWC/JTWC typhoon warning track positions. Figure 29 demonstrates these proce- dures, utilizing the 135 n mi average 24-hr forecast position error in obtaining the "danger area." This is necessary in order to expand the radius of 30-kt winds, given in the warning, by the average forecast error. Note the radius of 30-kt winds is usually greater on the right side of the storm track -- the dangerous semicircle. In this example, the radius to the 30-kt isotach is 200 n mi to the north and 150 n mi to the south. The 24-hr forecast predicts the radius to expand to 225 n rni to the north and 175 n mi to the south, Adding the average 24-hr forecast position error to the above figures forecasts a 24-hr danger area extending 350 n mi to the north and 310 n mi to the south. The 48- and 72-hr forecast positions given in the FWC/JTWC warning provide for a 275 n mi and 400 n mi average forecast error, respectively. Section 6 of Appendix I to Annex W of COMNAVPHIL OPORD 201-72 discusses the criteria for setting local heavy weather readiness conditions and is reprinted in this study as Appendix D G.2 REMAINING IN PORT Remaining in port when the means to evade a storm is available is a decision that is contrary to most of the traditional rules of seamanship. However, if the decision to remain in port is made, it should not be made without considering - 48 - . — 1 CALCULATING DANGER AREA FOR MOVING TYPHOONS AND TROPICAL STORM! 24hr FORECAST POSITION CURRENT POSITION tt ^tff. ii i i i i p m nujjmum —————I — — ifrir'ftW" i ni wiM nrt H T i'iTT¥»«iwn» i iiir —M m Figure 29 . Method of calculating the danger area for rcoving ! typhoons andj tropical storms (from Commander, Seventh Fleet, OPORD 201-YR) - 49 every available fact concerning the impending storm and the port in which the vessel is berthed. In the case of Port Olongapo in Subic Bay the following points should be noted: 1. Securing to a pier or anchoring in the bay should be done prior to the onset of 20-kt winds to prevent undue difficulty in mooring. 2. No berths in Port Olongapo can be considered shel tered . 3. Once the decisions to remain in port has been made, any reversal in plans would be extremely dangerous. Subic Bay is a relatively sheltered harbor so any wave and wind actions experienced inside the bay would be greatly magnified outside the entrance to the bay and in the open sea. 4. The holding action of the mud and coral bottom is considered good and the danger of ships breaking loose in heavy weather is less in Subic Bay than in many other WESTPAC ports. For a detailed, in depth account of conditions in Subic Bay during the passage of a typhoon, see the case study contained in Appendix F. 6.3 EVASION When evasion of a tropical cyclone is being contemplated the importance of correctly assessing the threat posed by the storm and acting quickly so as to retain flexibility cannot be overemphasized. The following time table, depicted in Figure 30 has been set up for this purpose: I. An existing tropical cyclone, or potential develop- ment in area C with forecast movement toward Subic Bay: a. Review the material condition of the ship; sailing within 2-4 days is a distinct possibility b. Reconsider all maintenance activities scheduled to exceed 48 hours. 50 - Xi V a u • Di+> cu a (3 0) E v C) c > m g w -p • -M >i td cn m h U co •H 3 CD c H o O m T3 (L) 0) to •H tf XX! (d K -P >i ftJ rt CO CQ H 5 u O 8 G en -H 6 O C) >i M u m rH rcs id QJ o H H 3 Qj CO ta M qj H a O • M o (3 ro 10 0) CI M E •H tJi-P •H fe 51 - II. A tropical cyclone entering area B with forecast movement toward Subic Bay. a. Operational plans should be made in the event sortie is ordered. b. Reconsider all maintenance activities scheduled to exceed 2 4 hours. III. A tropical cyclone entering area A with forecast movement toward Subic Bay. a. Execute evasion plans made in previous steps. The final decisions involving evasion of tropical cyclones rests with the commanding officer of the vessel involved. One of the more successful Pacific Ocean evasion tactics involves running downwind and down sea relative to the typhoon in order to reach a latitude south of the storm and in the navigable semicircle. The success of this method depends upon almost continuous reconnaissance coverage and the relatively slow movement and gradual expansion of the initially small area affected by severe winds that is characteristic of typhoons at low latitudes (Somervell and Jarrell, 1970). For a ship in or near Subic Bay the following evasion techniques for the more common threat situations are suggested: 1. Tropical cyclone forecast to pass north of Subic Bay: a. Evasion should be to the wes t- southwest since units are already in the navigable semicircle and will remain there. 2. Tropical cyclone forecast to pass east of Subic Bay: a. Evasion should be to the west-southwest since an eastward passing tropical cyclone may have already started recurvature and a westward heading will keep the ship in the navigable semi ci rcl e. - 52 .. 3. Tropical cyclone forecast to pass south of Subic Bay: a. Evasion should be to the west-southwest. This decision should be made as early as possible to preclude a rendezvous with the storm. It should be noted that some tropical cyclones do generate in the South China Sea each year. However, their normal tracks are to the west and/or north and should not present a threat to units in the Subic Bay area. In all cases careful monitoring of the storm should be conducted to permit the utilization of the proper evasion technique in the event of a sudden, unpredicted change in storm track." Whatever evasion decision is made, the following general comments should be considered: 1 When departing Subic Bay, ample time should be given to combat the heavy sea condition likely to be encountered at the entrance to Subic Bay. Crossing ahead of a typhoon should be accomplished well in advance of an approaching typhoon. Heavy swells may be encountered ahead of an advancing typhoon considerably before the occurrence of strong winds. Such swells may decrease a ship's maneuverability and speed of advance, preventing clearance of the typhoon track. ° At certain times of the year, particularly the peak typhoon season, the possibility exists that two or more tropical storms are present at one time. This would greatly complicate any evasion planning and executi on See Appendix E for discussions and examples of the extent to which sea state and wind speed reduce the speed of advance of a vesse 1 53 - 7. CONCLUSION Previous texts classifying Subic Cay as a typhoon haven have done so wi th certain reservations or qualifications. It is true that many ships have successfully weathered the fury of the numerous typhoons that have affected Subic Bay. However, it is also a fact that Subic Bay has never really been tested by the passage of a truly severe tropical cyclone. Those storms whose eyes have crossed directly over Subic Bay have been relatively weak storms; in the case of severe tropical cyclones the eyes have only come close, with the strongest winds missing Subic Bay by 50-100 n mi and the remaining winds being further reduced by the topography of the surrounding terrain. After considering the above facts and many discussions with experienced personnel at Subic Bay, it is the conclusion of this study that, although Subic Bay does provide some degree of shelter from typhoon passage, it should not be considered an "unqualified" typhoon haven. The sheltering effect provided by the surrounding terrain qualifies Subic Bay as a much safer port in heavy weather than Hong Kong, Kaohsiung, or Chilung (Keelung). However, large combatants (CVA, cruisers, etc.) would find the relatively small size of Subic Bay detrimental and they can generally withstand the rigors of evasion at sea. The cost in terms of time and money would be small since the evasion route would be short and direct. Smaller craft, given ample warning time, should also be able to evade into the navigable semicircle. If ample warning time is not given, or the means to evade does not See Appendix r for abstracts of statements from command' ing officers of ships located at Subic Bay during the passage of Typhoon " I rma " in Hay, 1966. - 54 - exist, relatively safe typhoon anchorages are present in the inner basin of Port Olongapo for a limited number of small vessels. From Appendix F it is evident that certain anchor- ages close to the western shore of the bay also provide some degree of shelter. To aid commanding officers in rapidly evaluating the threat posed to Subic Bay by an individual tropical cyclone, and to aid in decisions thereafter, Figure 31 has been incorporated into this text. Figure 31 is an operationally oriented flow diagram summarizing the locations of the various sections contained in this study. - 55 - . I . : ) TROPICAL CYCLONE DE Vf OPMLNl I .'I WESTPAC To determine whether tropical cyclones vjj 1 or ^i 1 1 net affect the area within 400 n mi of Subic Cay, refer to^ a. Section 6.1 (p. 48) which describes tropical cyclone warning information. Examine present warnings. b. Monthly western North Pacific el ImatologicaT typhoon tracts in Appendix A (pp. 78-69). c. Section S (pp. 23-47) - tropical cycio-e clf^itology for Subic Bjy. In particular Figures 13-?4 (pp. 35-41) tne percent threat analyses and Figures 25 and 26 (pp. 43-",;) the tracks of gale associated storms. 77 WILL AFFECT SUBIC BAY WILL HOT AFFECTFFEC SUBIC CAY b. Figures 25 and 26 (pp. 43-44) the tracks of gale associated storms. c. Sections 5.1 (pp. 23-34) and S.2 (pp. 34-46) with emphasis on Figure 27 (p. 45) for the position of past storm centers when >22 kt winds began HO ROPICAL CYCLONE IS NOT A at Subic — Bay and Figure 28 (p. 46) for tkre; ,_j THREAT TO SUDIC BAY the position of past storm centers when — TO >34 kt winds began at Subic Bay. SUBIC BAY Continue to ronitor storn -lovement; be alert for significant changes. TV THREAT TOIO SUBICS BAY 1L TROTICAL CYCLONE WILL POSE A THREAT TO SUBIC SAY EVASION REMAINING IN PORT With the expectation of a threat to If the ship is to remain in the port, co-nanders should ensure the port , re'er to readiness of evasion procedures. Refer to: a Section 6.2 (pp. 48-50) , a. Section 6.1 (p. 48) and 6.3 "Remaining in Port." (pp. 50-53) which cover the major aspects of evas ion at sea b. Section 4.4 (p. 2?) and Appendix C (pp. 92-33), "Harbor 5.3 for b. Section (p. 47) discussion Faci 1 ities." of wave action at Subic ?>*y , and Appendix T effect on - (pp. 97-100) showing the speed c. A p p e n i i » (pp. 9 4 <> of advance of wind and ica conditions. "Heavy '.. "ati.er PI an for the Pni 1 ippines. c. Appendix D (pp. 94-96), "Heavy Weather rian' for the Philippines. Figure 31. Flow diagram for Subic Bay. - 56 - 8 . MAN I LA 8.1 GEOGRAPHICAL LOCATION AND GENERAL DESCRIPTION Manila is the largest city in the Philippine Islands and is located on the eastern shore of Manila Bay (see Figure 5). Manila Bay is approximately 30 statute miles long, 23 statute miles wide at its widest point, and includes an area of 770 square miles. The entrance to Manila Bay is divided into two channels by Corregidor Island and Caballo Islands. These channels are named North Channel and South Channel, and both are deep and clear of obstructions. 8.2 TOPOGRAPHY Figure 32 depicts some of the topographical features surrounding Manila and Manila Bay. The Sierra Madre mountains to the east and the mountains on the Bataan Peninsula help to shelter Manila Bay from severe winds. Figure 33 depicts the bottom topography of Manila Bay. The depths of Manila Bay range from over 180 feet in the entrance to about 90 feet in the center, decreasing gradually to the shore. Note that the bay is very shallow in some places which, along with the relatively poor holding action provided by its sand and soft mud bottom, is why Manila Bay is not considered a haven during typhoon passage. 8.3 MANILA HARBOR The port of Manila consists of the North and South Harbors, both of which are protected by breakwaters. Figure 34 is a diagram of Manila Harbor. The Pasig River separates the two harbors and is navigable to a distance of one mile from its mouth by small vessels drawing up to 10 feet. The North Harbor is the smaller of the two harbors and is used - 57 Figure 32. Topographical map of Luzon showing approximate elevation above sea level and the location of Manila. I 58 - >1 PQ H(6 •w (0 -H u p o o o Q(!) n 0) •H En 59 ELEVATIONS roSPTHS) I* FEET ABOVE (SELOVY'i SEA LEVEL i- iJv^K - -.-rt,«»«<-7»v»^a«>«-ja»»M-Tmc>«M<3»fc. n».'«MM)WM Figure 34. Manila Harbor plan showing the location of piers and anchorage areasj which can be assigned to U.S.. Navy and contracted DOD vessels. I - 60 - solely for inter-island shipping. The South Harbor is used for large ocean-going vessels and is the harbor that will be considered in this study. 8.4 HARBOR FACILITIES There are five odd-numbered piers that extend south- eastward from the northern side of South Harbor] These piers contain the principal deep-draft berths and range in depth from 9 to 36 ft. Pier characteristics are not standardized and are contained in Appendix B. There are anchorages, both inside and outside the breakwater, for an unlimited number of vessels of all classes. The anchorages range in depth from 8 to 22 fathoms with less than adequate holding ground. It should be noted that with the return of NAS Sangley Point to Philippine control, U. S. Navy and DOD contract vessels no longer' are assigned special anchorage areas. - 61 . 9. TROPICAL CYCLONES AFFECTING MANILA 9.1 CLIMATOLOGY Refer to section 5.1 for the tropical cyclone climatology of Manila. 9.2 HIND AND TOPOGRAPHICAL EFFECTS In the 19-yr period from 1955-1973, for the months June- Decernber a total of 83 tropical cyclones approached within o 180 n mi of Manila. This is an average of more than four tropical cyclones per year. The largest number of tropical cyclones approaching Manila in any single year was eleven in 1964. Table 2 groups the above 83 tropical cyclones according g to the wind intensity that they produced at Manila. Of the 83 tropical cyclones concerned, 28.5% resulted in strong winds (>;22 kt) at Manila and only BA% resulted in gale force winds there (>34 kt) Table 2. Extent to v/hich tropical cyclones affected Manila during the period June-December , 19 55-19 73. Number of tropical cyclones that passed 83 within 180 n mi of Manila Number of tropical cyclones resulting 24 in strong winds (_>22 kt) at Manila Number of tropical cyclones resulting 7 in gale force winds (>34 k';) at Manila 8 From Chin (1972) for years 1955-1970 and from Annual Typhoon Reports for 1971-1973 (U.S. FWC/JTWC, 1971-1973). q The wind data for Manila is from NAS Sangley Point for the years 1955-1968. For the remaining years, 1969-1973, the data were taken from a wind gage at the mouth of the Pasig River and are verified to be representative of the wi nd in Manila Bay. - 62 It is apparent from Table 2 that Manila must be an extremely sheltered harbor. Figure 32 depicts the sheltering effect of the terrain surrounding Manila. The Sierra Madre mountains to the east and the Bataan Peninsula to the west effectively serve as a wind barrier for Manila. When gale force winds do appear they are generally tunneled from the Linguyen Gulf through the Pampanga Valley to Manila. Figure 35 depicts the tracks of tropical cyclones occur- ring during the period 1955-1973 that resulted in gale force winds at Manila. From their orientation and a comparison with the percent threat figures in section 5.1 it is evident that tropical cyclones approaching from the east and east-southeast represent the primary threat to Manila. Figure 36 shows the position of tropical cyclone centers when the wind first and last exceeded 22 kt at Manila. Figure 37 shows the positions of tropical cyclone centers when the wind first and last exceeded 34 kt at Manila. Notice that the relatively few tropical cyclones resulting in gale force winds began affecting Manila very close to, or after, tropical cyclone passage. Those tropical cyclones resulting in strong winds did not affect Manila until the cyclone centers were very close to the east coast of the Philippines, but tropical cyclones several hundred miles to the west of the Philippines still had an effect on the winds experienced at Manila. 9.3 WAVE ACTION Quantitative information on wave height data for Manila Harbor or Manila Bay is not readily available. However, when a typhoon is over or near the Linguyen Gulf and tunneling winds through the Pampanga Valley to Manila, the strongest winds are experienced in the bay. These strong winds present more of a hazard to ships in the bay than do the waves they generate. 63 ^ ^^ h (i> M tJi M wo u M *U r-l id tJi 5 •H & ^— ^ • O co p r~- id CT\ •H H O 1 O in to ID to CTl oi .h tfl 6 Q) o Ci u Ho M-l O id >l+J C) id H T3 id C Hu O cvo o a> n w +J cd m —CQ o (0 . A^ id U rH id •h S-l r; EH u *M • -p m cd ro w 0) rd H C 3 •H tJi •rH fc - 64 t> c CO +J CO Hu M-l CO n3 £ -H £ +J ^'-> cn m cm r> A ]cn rH G 1 q in Xi m I5c* rH 10 H E a o +J M fi«H a U RJ P c^O <3 o rH C u o >1 o 'ri fCJ rci Ucq -H^- (h O u • +J (3 rH W-H O G astf O •H-P P (3 •H 10 'C! O O d, M !-l 3 • O VD O ro O O-P M CO 3 rd Cr>H •rHb 65 - * «d c Rj +J CO Hu m M10 c iH> •P ^4 --~ • «=l« ro n r- A P^ rH r" BJ m _rj min rH 01 M e O o 1 1 K^M O o id .D CJ d p •O o iH c O o >i V T) G) iH to Rj d Ocq •rH *— P, o u • -p Hd •H .'J -P d •H r 11 d CJ ex. u u r» • u r- CJ CO o - 66 - Due to the relatively short fetch and shallow bottom, the generated waves could reach ten feet or more in significant height but should not build to excessively high levels. The swell coming into the bay is damped considerably by Corregidor Island which sets in the mouth of the bay. It serves to split the swell and reflect it to either side. The possibility of shoaling, the building in magnitu.de of waves when the water depth reaches one-half their wavelength, occurs when the reflected swell reaches the shallower portions of 10 the bay. See Hydrographic Office Pub No. 604 for a detailed discussion on shoaling. - 67 - 10. PREPARATION FOR HEAVY WEATHER 10.1 TROPICAL CYCLONE WARNINGS Tropical cyclone warnings including 24-, 48-, and 72-hr forecasts are supplied by the Fleet Weather Central/Joint Typhoon Warning Center (FWC/JTWC) located on Guam. COMSEVENTHFLT OPORD 201-(YR), Annex W, describes the proce- dures and techniques to be used when plotting the FWC/JTWC typhoon warning track positions. Figure 29 demonstrates these procedures, utilizing the 135 n mi average 24-hr forecast position error in obtaining the "danger area." This is necessary in order to expand the radius of 30-kt winds, given in the warning by the average forecast error. Note the radius of 30-kt winds is usually greater on the right side of the storm track -- the dangerous semicircle. In this example, the radius to the 30-kt isotach is 200 n mi to the north and 150 n mi to the south. The 24-hr forecast predicts the. radius to expand to 225. n mi to the north and 175 n mi to the south. Adding the average 24-hr forecast position error to the above figures forecasts a 24-hr danger area extending 350 n mi to the north and 310 n mi to the south. The 48- and 72-hr fore- cast positions given in the FWC/JTWC warning provide for a 275 n mi and 400 n mi average forecast error, respectively. Section 6 of Appendix I to Annex W to COMNAVPHIL OPORD 201-72 discusses the criteria for setting local heavy weather readiness conditions and is reprinted as Appendix D in -his study. Figure 38 presents the visual storm warning signals used in Manila harbor. 10.2 REMAINING IN PORT Remaining in port when the means to evade a storm is available is a decision that is contrary to most of the traditional rules of seamanship. However, if the decision to 68 VISUAL STORM WARNING SIGNALS DAY NIGHT SIGNAL SIGNAL ONE BALI.. — Winds of unspecified direction, speed from 22 to 33 knots, are expected within 24 hours in the vicinity of the signal. The direction may be indicated by a cone or cones hoisted below the ball. PRECAUTIONS.— Small boats should remain in harbors and those at sea should seek shelter. Larger craft should proceed with caution. ONE CONE — POINT UPWARD.— Winds from the NW quad- rant (north, northwest, 3nd west) of speed between 34 and 63 kr.cts ® (39 and 72 mph) are expected to blow within 21 hours in the area* of the signal. PRECAUTIONS.— All ships should take shelter in areas pro- tected from the NW quadrant winds. No vessels underway while thi3 signal is up. Steam may be necessary to assist anchors. ONE CONE — POINT DOWNWARD. — Winds from the SW quadrant (west, southwest, and south) are expected to blow within 24 hours at a speed between 34 knots and 63 knots (33 mph ajid 72 mph). © PRECAUTIONS.— All ships should seek shelter in areas pro- tected from winds from the SW quadrant. TWO CONES — POINTS UPWARD.— Winds from the HE .ju*dr»nt (north, northeast, and east) of speed between 34 knots © A and 63 knots (39 mph r.nd 72 mph) are expected within 24 hourr. © PRECAUTIONS.— All ships should seek shelter in an area protected from winds from the N't] quadrant. TWO CONES— POINTS DOWNWARD —Winds from the SE quadrant (south, southeast, and cast) of speed between 34 and 63 knots (39 mph and 72 mph) are expected within 24 hours. © PRECAUTf ONS. — Ships should take shelter in an area protected from winds from the SE quadrant. ONE DAR.—The wind will be blowing from the direction and at the speed indicated by the cones, but will shift within 12 hours ia a NONE clockwise manner; that is, a wind blowing from the HE will veer to the SE; one from the SW will veer to the NW, etc. TWO IIARS.— The wind will be blowing from the direction end at the speed indicated by the cones but will shift within 12 hours NONE in a counterclockwise manner; that is, a wind blowing from the N'E will back to the NW; one from the SW will back to th= SE, etc. CROSS. — Typhoon winds of unspecified direction, speed 64 knots (74 mph) or greater, are expected within 24 hours. This (W) signal may be raised in combination with another to specify the # expected direction of the winds. © PRECAUTIONS —Extreme safety measures must be taken to © insure the safety of life and property. Wave-, and swills in the open sea will be exceptionally high Visibility will be seriously affected. Figure 38. Visual storm w< ling signals which are utilized at South Harbor in Manila (II. 0. Pub. No. 90, 1969) . - 69 remain in port is made, it should not be done without every available fact concerning the impending storm and the port in which the vessel is berthed. In the case of Manila harbor the following should be noted: 1. Securing to a pier or anchoring in Manila Bay should be done prior to the onset of 20-kt winds to prevent undue difficulty in mooring. 2. No berths in Manila harbor can be considered shel tcred. 3. Manila Bay is extremely shallow in places and contains relatively poor holding ground since the bottom consists of soft mud and sand. 4. Marveles harbor is the most secure harbor in times of weather stress, but it is only large enough to accommodate two or three ships safely. 5. South harbor in Manila harbor is a crowded harbor and at any given time can contain many merchant ships. Some of these vessels may be equipped with inadequate or poorly maintained mooring gear. As a result, it is not uncommon for them to break loose and cause damage to other ships in port. 10.3 EVASION When evasion of a tropical cyclone is being considered, the importance of correctly assessing the threat posed by the storm and acting quickly so as to retain flexibility cannot be overemphasized. The following timetable depicted in Figure 39, has been constructed for this purpose: 1. An existing tropical cyclone, or potential develop- ment, in area C with forecast movement toward Manila: a. Review the material condition of the ship; sailing within 2-4 days is a distinct possibility b. Reconsider all maintenance activities scheduled to exceed 48 hours . - 70 - & u id o M • ft-P & G r3 •P • X Hid M •H c 8-1 d •^ CH c M id o IH a 1 \ to •H -3 X 0J id U) (d -p .Q rj a) *. j-t id 5 a 0) rd c S C) H £ U o >l t-l u IH H T} id CJ • n CTVn id w C) 0J 5-1 B 3 •H tr>-P -H fM - 71 . A tropical cyclone entering area B with forecast movement toward Manila: a. Operational plans should be made in the event sortie is ordered. b. Reconsider all maintenance activities scheduled to exceed 24 hours . A tropical cyclone entering area A with forecast movement toward Subic Bay: a. Execute evasion plans made in previous steps. The final decision involving evasion of tropical cyclones rests with the commanding officer of the vessel involved. One of the more successful Pacific Ocean evasion tactics involves running downwind and down sea relative to the tropical cyclone in order to reach a latitude south of the storm and in the navigable semicircle. The success of this method is due to almost continuous reconnaissance coverage and the relatively slow movement and gradual expansion of the initially small area affected by'severe winds that is characteristic of typhoons at low latitudes. For a ship in or near Manila, the following evasion techniques for the more common threat situations are suggested 1. Tropical cyclone forecast to pass north of Manila: a. Evasion should be to the west-southwest since units are already in the navigable semicircle and will remain there. 2. Tropical cyclone forecast to pass east of Manila: a. Evasion should be to the west-southwest since an eastward passing tropical cyclone may have already started recurvature and a westward heading will keep the ship in the navigable semi ci rcl e - 72 - Tropical cyclone forecast to pass south of Manila: a. Evasion should be to ttie wes t-southwest . This decision should be made as early as possible to preclude a rendezvous v/ith the storm. It should be noted that some tropical cyclones do generate in the South China Sea each year. However, their normal tracks are to the west and/or north and should not present a threat to units in the Manila area. In all cases careful monitoring of the storm should be conducted to permit the proper evasion technique to be employed in the event of a sudden, unpredicted change in track by the storm. Whatever evasion decision is made the following general comments should be considered. 1. Even weak typhoons crossing the Philippine Islands can quickly result in strong winds in Manila Bay. The decision to sortie should be made far enough in advance to preclude difficulties in exiting Manila Bay. 2. Crossing ahead of a typhoon should be accomplished well in advance of the approaching typhoon. Heavy swells may be encountered ahead of the advancing typhoon considerably before the occurrence of strong winds. Such swells may decrease a ship's maneuverability and speed of advance, preventing clearance of the typhoon track.*' 3. At certain times of the year, particularly the peak typhoon season, the possibility exists that two or more tropical storms are present. This would greatly complicate any evasion planning and execution. See Appendix E for discussion and examples of the extent to which sea state and wind speed reduce speed of advance . - 73 11. CONCLUSION It is the conclusion of this study that Manila harbor is not a safe harbor and Manila Bay is not a safe refuge during a passage of a typhoon. The policy of the Port Captain of the South Harbor, Manila, is to evacuate all vessels at least 24 hours prior to typhoon passage. The harbor is extremely busy and congested with primarily merchant and commercial shipping vessels. These vessels are, more often than not, equipped with inadequate or inferior mooring equipment and they may evacuate to any area in Manila Bay outside the con- fines of South Harbor. Because of the danger of ships breaking loose from anchor during the storm and the shallowness of the bay, it is recommended that all U. S. Navy or contracted DOD vessels sortie from Manila Bay as well as from Manila harbor. Since the evasion route is generally southwesterly into the South China Sea, the sortie should be relatively short, low in operating costs, and free of peril. To aid commanding officers in rapidly evaluating the threat posed to Manila by an individual tropical cyclone, and to aid in decisions thereafter, Figure 40 has been incorporated into this text. Figure 40 is an operationally oriented flow diagram summarizing the locations of the various sections con- tained in this study. 74 - TROPICAL CVCLOIIE DEVELOPMENT I 'i WE5TPAC To determine whether tropical cyclones will or will not effect the area witnin 100 n mi of Manila, refer to: a. Section 10.1 (p. 68) which describes tropical cyclone warning information. Examine present warnings. b. Monthly western North Pacific cl i na tol ogi cal typhoon tracks 1n Appendix A (pp. 78-39). c. Section 5.1 (pp. 23-34) - tropical cyclone climatology for Manila. In particular, Figures 18-24 (pp. 35-41). the percent threat analyses, and Figure 35 (p. 64), the tracks of gale associatec storms . 71 rr~ WILL AFFECT MANILA WILL NOT AFFECT MANILA a 1L TROPICAL CYCLONE WILL AFFECT THE TROPICAL CYCLONE M ILL NOT AREA WITHIN 400 II HI OF MANILA AFFECT THE AREA WITHIN 400 N MI OF MANILA To determine whether the tropical cyclone will pose a threat (pass within Continue to monitor 180 n ni) to Manila, refer to: storm movement; be alert for significant changes. a. Section 10.1 (p. 68) which describes tropical cyclone warning information available. Examine present warnings being issued. b. Figure 35 (p. 64) the tracks of gale associated storms. c. Sections 5.1 (pp. 23-34) and 9.2 (pp. 62-63) with emphasis on Figure 36 (p. 65) for the position of past storm centers when ^22 kt winds began at Manila NO TROPICAL CYCLONE IS NOT and Figure 37 (p. 66) for the position of - THREAT ^ THREAT TO MANILA past storm centers when ^34 kt winds began - TO -V at Manila. MANILA Continue to monitor s torn nove-ent; bo alert for significant changes. n THREAT TO MAHILA Ai TROPICAL CYCLONE WILL POSE A THREAT TO MANILA EVASION REMAINING IN PORT With the expectation of a threat to If the ship is to remain in the port, commanders should ensure the port, refer to: readiness of evasion procedures. Refer to: a. Section 10.? (pp. 68-70), a. Sections 10.1 (?. 63) and 10.3 "Remaining in Port." (o?. 70-73) which cover the r.ajor aspects jof evasion at sea. b. Section 8.4 (p. 61) and r Appendix B (pp. 90-91), "Harbor t>. Section 9.3 (pp. 63-65) for Facilities." i discussion of v. a v e action at Manila, and Appendix E (pp. 97- ICO) showing the effect c. Appendix D (pp. 94-96). i on s^eed of advance of win:? and sea Heavy Weather Plan" for the Q 1 conceit , ons. Pnilippines and Figure 33 (p. 69), jj c. Appendix (pp. 94-96), "Heavy visual storm signals used at Manila y leather Plan" for the Philippines. p I Figure 40. Flow diagram for Manila. 75 - REFERENCES Brand, S. and J.W. Blelloch, 1972: Chang es in the character^ istics o f typhoon s crossin g the Phi 1 i ppi r.es . ENVPREDRS'CHFAC Tech. Paper No. 6-72." Brand, S. and L.D. Burroughs, 1972: Speed of tro pical storms and typhoons aft er rec urvature in the western N orth "Pacific Ocean. ENVPREDRSCHFAC Tech. Paper. No. 7-72. Brand, S., J.W. Blelloch, and D.C. Schertz, 1973: St ate of the sea around tropical cyclo nes in the v/estern North Pacific Ocean. ENVPREDRSCHFAC Tech. Paper No. 5-73. Brown, M . E . , 1974: An eva 1 uation of the harbors of Kaohsiung and Chilling ( Keel un g YT T a iwan as typhoon havens . ENVPREDRSCHFAC Tech. Paper No. 6-74. Chin, P.C., 1972: Tropi c al cyclon e climatology for th e China Sea and western Pacific from 188 4 to 1970 . Hong Kong: Royal Observatory Hong Kong, 207 pp. Crenshaw, R.S., Jr., Capt., USN, 1965: Naval Shi ph and"! ing . Maryland, United States Naval Institute, 533 pp. Gray , VI . M . , 19 70: A cli matolo gy of trop ical cyclo nes a nd disturbanc es of the W es tern Pacific wi th a suggested theory for ~th eir gen esi s/m ai nt enance . NAVWEARSCHFAC Tech. Paper No. 19-70. Harding, E.T., and W.J. Kotsch, 1965: Heavy W eath er G ui de . Maryland, United States Naval Institute, 209 pp. Johnson, J.W. and R . L . W i e g e 1 , 1955: Waves at Subic B.-y , Philippine Islands. Contract No. Y79349 , Bureau cf Yards and Docks, Department of the Navy, 34 pp. Lehr, P.E., R.W. Burnett, and U.S. Zim, 1957: Weather. New York: Sir; on and Schuster, 160 pp. Mautner, D.A. and S. Brand, 19 73. An e valuation of Hon g KoncL harbor as a typhoon haven . ENVPREDRSCHFAC Tech. Paper No. 9-73. Nagle, F.W ., 19 72: A numerical st udy_in optimum ship track routing climatology . ENVPREDRSCHFAC Tech. Paper No. 10-72 - 76 - . Palmen, E. and C.W. Newton, 1969: Atmospheric Circulation Systems . New York: Academic Press, pp. 472-486. Somervell, W.L. and J.D. Jarrell, 1970: Tropical cyclone evasion planning . NAVWEARSCHFAC Tech. Paper No. 16-69 (Rev) U.S. Commander Seventh Fleet, COMSEVENTHFLT 0P0RD 201-(YR), Annex W. U.S. Fleet Weather Central /Joi nt Typhoon Warning Center, 1970-1973: Annual typhoon report, 1970-1973 . Guam, Mariana Islands. U.S. Fleet Weather Facility, Sangley Point, Luzon, R.P., 1967: An evaluation of Subic Bay as a typhoon haven . (COMNAVPHILINST. 3140.2). Sangley Poi nt, Luzon, Republic of the. Phi li ppi nes , 49 pp. U.S. Fleet Weather Facility Yokosuka, Japan, 1967: Typhoo n havens Japan-Korea-Okinawa . Yokosuka, Japan, 145 pp. U.S. Naval Oceanographi c Office, 1969: Sailing directions for the Philippine Islands (H.O. Pub. No. 9 0^ NAVOCEANO"; Washington, D.C., pp. 103-129. U.S. Naval Oceanographi c Office, 1966: Techniques for fore- casting wind waves and swell (H.O. Pub. No. 604). NAVOCEANO, Washington, D.C., 37 pp. U.S. Naval Oceanographi c Office, 1974: Fleet Guide, Subic Bay (H.O. Pub. No. 918). NAVOCEANO, Washington, D.C., 45 pp. 77 - APPENDIX A Figures A-l through A-ll show monthly and half monthly (June to December) tracks of western North Pacific tropical cyclones (1946-1969) which were at one time of typoon intensity. The tropical cyclones have been placed into monthly categories according to the median date of their existence (from Gray, 1970). - 78 - fr c •H U 3 H3 CO G O O x ih >1 -p o u o s 0) e •Hp 0) g o to •p (d X! u •H x: criO s O to rH 0) 1 c vo o ^r l-l c^, U H >. u to u r-1 C3 (d Q) o >i •H Dj (0 o X c V rj Cj i^ M Eh 4-1 • S 1 c < h o 3Xu Atn-P Pu, - 79 ' d c •H M 3 'O 1ft a a o Si VU p>i a) u G) S o g •H • -P 0> lO 0) a% E -H o I W v.o s? P M id cH .a Ifi u M •H rj jS O £ >i w o 5 o •H M o >i »H o ,~^ cH 4-» rj H U fd •h .c P< C) -P n tn •4-1 HU •H m O — to >i ^ rH u p nJ •-3 >H H ^ o • £[ CM +i 1 a <; o fc a) u 0) p x: Cn-P •H Fn - - ; <*••("-- .."4 « L„- .N .^K^A^ir \«% t-fecn«as3t f - 80 , tr> C •H U 3 tl i -P u0) 0) ^ fl) g • H CTi +J VD CT\ 0) .H e 1 o vo w ^« en +J rH fO w C M o (v) •H i s i U m..— H rH f3 (3 U X! •H ft tJ O G H O JJ O en >i X rH u 3 rt hJ M H M-) • CI 6 1 C < o b 0) M a) 3 .c tP 4-> •H h - 81 - Hc M •o V) o o •P o u o o • 6 CD -H vo -P OA rH O I g vo o "* CO CD rH -P <3 co .c a U 0) •H >, to P d O O rH 4-1 O >i — O 4-1 rH rH fv3 u •H P O. co O M M-H 4-1 |i P r-r- !> 4-1 >-:,§ P V-' -I 10 10 3 .* C7> U 3 p rt < M - "V -. B m O • x: i 1 c v; j. <: o V7- 7 o •!l (••••v. tc •--../_ "---7"-* ; 1 Sj . il A ^T - -\"i< " •H I -J r - l-V--- -J fa m" • »4.. I.: *».,•:« -I-i I 1 - .. 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Ml At/',. /.: •H Cm ~£U - 36 - ^ t7> c •H H 3 'O to c o o C a >i -p O ^ OJ s • ct> o o E c^ •H H -P 1 vo 0) si1 e C?l o rH la tO 4-> H a td JZ >i u •H a) jc x; S -p to M o a C »H r-t ,— U m >l H u r3 X! r-i (3 'd u a •ri o Ch u o a M to -P ~-* m U o 0) a to u v -•-J o o d o M H '-M o (T\ 2 1 G < C) u o M o ^' tn-P •H 51 1^ - 87 URAMNaWMKJ * » h fc h " fc > _ __» m ; g •H m 3 'a 0) c o o ^ ill >1 +> a m >0) H* 0) e •H +J O Ot-, [fl +> C r; 0\ D \o •H cr> XX rH *> | 10 Of sr ti C\ a rH o rH 10 o u >1 rt u O >i rH f3 o o .d •rH -p p-l -i C) u dOTS? « n +» m S- 4 14-1 M o o n - T V. v^ - . 'i M a 1-V; u > tr. n S I; B M-J Ho 3 1 c •• ,.-> < •;•> c\ /,(i « • \m fc o u o 3L 3 si -V-:- Cr> -P •M Cn U— - ^o^.iis^W* »—I— >»» w»»»»«*^« - 08 - q •H u V3 CO c o A a >i +> Q) U 0) S 0) e •H -P 0) g o to p (0 X! CD U vo •H m £ rH S ^1 to ** G) t-4 U) u >i RJ u C) H >1 ftf 0) OX! •Ha -p n n o P m M-l u o Q) -q UJ b X CJ u o fC O M Q H •H O •-{ Si rH +3 1 C < g fc-i - 89 . APPENDIX B The following is a summary of pier, anchorage, and buoy facilities available in the South Harbor of Manila. (H.O. Pub. No. 90, 1969.) 1 Anchorage s There are 15 available anchorages in South Harbor of Manila ranging in depths from 17 feet to 32 feet. There are unlimited anchorages outside the breakwater in Manila Bay in depths of 6 to 22 fathoms. 2. Piers Table G-l lists the piers available in South Harbor and their characteristics. 3. Facilities Pier 5 contains a 50-ton crane and 2 cargo sheds. Pier 9 is the most modern of Manila's port facilities,' having covered cargo sheds and water piped to it. Pier 9 contains one 17-ton crane and four 5-ton cranes. Mobile cranes are available at Luzon Ste vedori ng and floating and crawler cranes are available at Fernandez Shipyard, Sang ley Point. Two floating cranes of 100-ton capacity each. YD 115 and 171, are also available. A /.5-ton self-propelled floating crzu^ , YSD 63, is available from Ship Repair Facility for small 1 i Fts. Thirteen mobile cranes of varying capacities and radii are located in the area. Three cruiser type cranes are also available. 90 Table B-l. Piers available in South Harbor, Manila Depth Name Dimensi ons Berth Number FWD AFT Pier 3 1080' X 336' 1 26' 28' 2 30' 34' 3 28' 34' 4 26' 28' Pier 5 1075' X 333' 1 23* 27' 2 27' 30' 4 28' 29' 5 23' 28' Pier 9 1095' X 339' 1 24' 28' 2 27' 30' 4 28' 30' 5 24- 28' Pier 13 1300' X 300' 1 24' 27' 2 27' 28' 3 28' 30' 5 28' 30' 6 27' 28" 7 24' 27' Pier 15 1100' X 340 1 24' 28' 2 28' 32' 4 27' 32' 5 22' 26' - 91 . APPENDIX C The following is a summary of piers, wharves, anchorages, mooring buoys, and other facilities available in the Port Olongapo complex in Subic Bay (H.O. Pub. Mo. 918, 1974). I . Anchor ages There are more than 100 safe anchorages in 12 to 25 fathoms of water with soft mud or coral bottom. Under normal conditions these anchorages are satisfactory, however with strong southwesterly winds in excess of 35 kt ships must steam to their anchors to prevent dragging. 1 1 . Buoys A total of 18 mooring buoys are presently available in the Port Olongapo complex. Six of these are deep draft mooring buoys. Buoy numbers 3, 19, 21, 23, 24, and 25 can be used for cargo operations and can accommodate vessels of 10,000 tons. III. Piers a nd Wharves Table C-l lists the piers and wharves available in the Port Olongapo complex and the characteristics of each. IV Facilities Alava wharf contains one 50-ton portal crane which is mounted on rails. The maximum re. Jius for the main hook is 115 feet, it is equipped with a boom extension and it can service all carrier antennas. Another portal crane is mounted on Rivera Point East. It has a 25-ton capacity with a 90-foot maximum radius for the mai n hook - 92 — — — — — — — — —— — — — — I -tJ 4- 4- 4- 4- 4- 4- 3 C c i- .Q 5- jQ $- jQ S- .O i- ja XJ S- +J QJ J3 o fO n3 res (T3 ra ra rcf ra rO rO r0 ra •i- E CO •1 • JZ r— _C i .c i JC .c i n— -£= r— CO QJ i +-> 5 to S tn 3 m 5 tn 5 in to 3: QJ > 00 u in V) m in in in QJ -O ro m 3 I— 0J QJ r— cu a> r~ 0) cu r— OJ QJ r— 4-> c Q. CJ aj