The Theater of Operations

The Sea

The Marshall, Caroline, and Pelew Islands form a "cloud" of islands, stretching east and west between the parallels of 4 and 1230' North, and the meridians of 134° and 172°30' East. The Marshall Islands consist of two chains of low coral atolls composed of about 30 atolls or groups. The Caroline Archipelago, including the Pelews, comprises about 48 groups, of which 43 are of low coral formation, the other five being of high (basaltic) formation and encircled by fringing reefs (extending from the shore-line, practically bare at low tide).

Perhaps there is no other area in the world where navigation is more difficult than in that under consideration. Not only is it a veritable "cloud" of islands and reefs, but it has never been accurately charted. Oftentimes navigation is dependent entirely upon the eye. Stationed at the masthead, preferably with the sun high and aft, the navigator directs the course amidst the patches of discolored water, light brownish in about three feet, clear green to darker at a fathom or more. Numerous vigias (reported reefs of which the existence or exact location is doubtful) have not yet been verified. One particular difficulty in clearing up charts has been that Nature here practices unusual deceptions in the way of cloud reflections, volcanic disturbances and movements of marine animal life, all causing discoloration or movement of the water surface similar to that caused by reefs. Another danger to navigation is that the islets and reefs usually rise abruptly from great depths, and most of the islands, being low, are very difficult to see at night.

The ocean currents to be met with are irregular and uncertain and are much influenced by the winds. South of 8° N. the currents run between east and NNE from one-half to two knots per hour. North of that line the currents will generally be found running to the westward at the late of 1%miles per hour. When near the island groups, the currents are sometimes deflected and always accelerated. The tidal streams in atoll and reef passages are generally very strong and cannot "be calculated upon to turn with high and low water.


The tide undulation among the islands is of small elevation, having a mean height of about four feet, and varying from 1 to 7 feet.

The Air

The climate is considered very good, for the tropics. The temperature is extraordinarily uniform, the average annual temperature being about 80°. Clouds, decreasing through the day, are very prevalent, as is also rain, which falls generally throughout the islands on about 20 to 25 days in every month. Thunder storms are rare. Most rain falls during the months of June to October. The rainfall increases from north to south; droughts are prevalent in the northern islands.

In the Marshall Islands the NE trade blows from December to April, although in some years it blows very lightly or not at all. In these cases a SE variable wind blows. During the NE trade the weather is often squally, the wind shifting to E. and S. and back again. East winds blow from May to November, but are irregular as to force and duration. From August to November these winds are at times interrupted by strong SW winds (storms) and calms.

In the Caroline and Pelew Islands the NE trade blows with tolerable freshness and steadiness from about October to May. The SW monsoon blows from June to August, frequently broken by short spells of easterly trades. Strong S gales (storms) may blow in August or September. This is also the season for light winds and calms, the ban[e] of sailing craft.

Hurricanes or typhoons are unknown in the area under consideration, although typhoons in the China Sea are sometimes felt in the more westerly groups during the months from August to November. Yap has been subjected to several severe storms or typhoons.

By reason of prevalent clouds, rainfall and shifting winds, the air conditions do not seem to favor aerial navigation. These disadvantages are somewhat neutralized, however, by the numerous island groups where landing refuges may be available.

The Land

There are two distinct types of islands in the theatre of operations, as follows:


  1. The Coral type (including all but five of the islands): These islands have formed on strips or rings of barrier reef surrounding a central lagoon, thus forming atolls. Their formation is due to constant and long continued disintegration of the barrier reefs, combined with the piling up of drifting seaweed and littoral vegetation, followed by a growth of the latter and ultimate decay. The shape of these islands, or keys, is generally long and narrow, the usual elevation not exceeding 40 feet.

    The terrain of the coral islands is remarkably uniform. On approaching from the sea, one strikes first the gray barrier reef, rising abruptly out of the water; then, traversing coral shallows of varying width, one comes to a white sand beach extending up to high water mark. Then, proceeding inland, one finds coarse creeping grass and vines which bind the coral sand-soil with their matted roots, and also "flame," pondamus and hibiscus trees and the usual tropical growth, or cultivated areas - coconut trees, bananas, tare, yams, etc.

    Water for drinking purposes is obtained by storing rain water, or from green coconuts (almost always to be found); for washing and bathing purposes by digging holes or wells in the center of the island. Well water on some of the larger keys is sometimes used for drinking purposes, but it is more or less brackish.

    Coral formations are always well drained, and good camp sites may be found. It is probable that the beaches form the only available landing fields for land airplanes.

    The lagoon anchorages formed by the atolls are sometimes of vast extent --up to 75 square miles. In many cases, however, they are so badly fouled by coral heads as to render their use by capital ships very hazardous. In other cases only certain portions of the lagoon are foul, there remaining in addition extensive stretches of clear anchorage space for ships of any draft.

    Passages or breaks in the barrier reef, generally narrow and varying in depth, connect the encircled lagoon with the open sea. In the case of the small lagoons, the passages may suffice only for the passage of small boats, but the larger atoll anchorages always afford at least one navigable passage for the largest ships.

  2. The Volcanic (basaltic) type (including the islands of Kusaie, Ponape, Truk (or Hogolu), Yap and Babelthuab (all with detached inlets)):


    These islands, with the exception of Yap (which is similar in formation to the volcanic section of Guam), are high masses of basaltic formation projecting from the sea and surrounded by fringing and, in some cases, barrier reefs. The islands are irregular in shape and vary in area from 35 to 150 square miles and in elevation from 1000 to 2900 feet. In places there are lagoons between the barrier and fringing reefs which permit of the navigation of the largest native boats at all stages of the tide. The fringing reefs are dotted here and there with volcanic islets, coral keys and flower-pot islets (so called from their profile).

    The terrain of all the volcanic islands is practically the same. As one approaches from the sea, he probably strikes a barrier reef and a lagoon before coming to the fringing reef. Crossing the latter reef brings one to a belt of mangrove trees, interspersed with narrow, tortuous waterways, the extent of the belt evidently depending upon the alluvium deposit which has been washed down on the coral reefs from the volcanic slopes in the rear. Passing through the mangrove belt, one strikes a belt of nipa and betel-nut palms, tree-ferns and other jungle growth, or cultivated areas: coconut and bread-fruit trees, taro, yams, kava, etc. Proceeding up the mountain slopes, one finds good timber trees and jungle, together with grassy plateaus among the heights. In the case of Yap Island, the country is more open, and the mangrove belt practically disappears, being replaced by a belt of coconut trees about half a mile wide.

    Interior communications are generally few and poor, the principal communication being via small native boats and coastwise schooners. Population and activities are concentrated in the coastal plains and lower valley stretches.

    There is good and plentiful potable water on the larger islands as a rule, although the people of Yap have to depend upon stored rainwater to some extent in dry years.

    Good camp sites are to be found. The availability of landing fields is not known, but it is probable that they are few and that more or less labor will be required to put them in condition for use.

    The anchorages formed by the indentations in the islands, together with the [island] reefs, although comparatively numerous, are limited in area and suffice only for a few large vessels.


    Besides, the passes connecting them with the open sea are generally narrow, tortuous and shallow. They would, however, form excellent bases for the light draft of a fleet, as they are generally protected from both wind and sea.

The Native Population

All islands and islets (excepting bare rocks) are inhabited, at least in certain seasons. The native inhabitants, numbering about 70,000, are a combination of the black, brown and yellow races: the remnants of successive waves of population rolling outwards from Indonesia. They were formerly fearless navigators and bold fighters, with high physical endurance and intelligence. This is amply proven by old legends and by certain ancient stone constructions yet to be seen. However, with the advent of the vices of the whalers, the ingrown fanaticism of missionaries and of bungling European colonization methods, the native gradually exchanged both barbarous vices and virtues for western vices and the more or less lazy and deceitful qualities of the usual native convert. All tribes are now supposed to be Christianized, although it is well known that there are occasional lapses back to old practices and many superstitions indulged in through remembrance of their former religion; a combination of ancestor worship and native spiritism. The opening up of trade, with its stimulus to industry, has also had a tendency to quiet the people and atrophy their native fighting propensities.

By reason of the mental upheavals caused by the outside influences mentioned, the natives are now in a transitory state. Lately their mental indigestion has been further complicated by the occupation of the islands by the Japanese, who have initiated an extensive educational program designed to loyalize the people to Japan. This probably includes a change to the Japanese religion, which somewhat resembles the former religion of the islanders. These widely varying influences have not only tended to alienate the natives from their former methods of life, but also have confused the native mind and broken up racial and tribal unity. It may be said that the tribal characteristics of today are in the main varying characteristics of the individuals who, for the most part, give trust and loyalty to none but themselves.

During our operations, a wise dispensation of money and preferment and a recognition of native leadership and customs will be the main factors in ensuring tranquility. Native resistance at the outset will depend mainly upon the ability of the Japanese to gain the friendship of the people and bring them to war temper. In some cases it is likely that they will be loyal and traces of the old-time military morale will flash out in ambush, rushes, massacres and obstinate palisade defense in the jungle, and surprise landings or boardings among the reefs.


The dialects spoken among the islands are practically as numerous as the island groups themselves. Most root words can be traced to Asia, but they have been so modified by more modern influences (Malayan in particular) as to be almost unrecognizable. The dissimilarity in dialects has also been enhanced by long isolation from the mainland and between groups. The dialects spoken in the Marshall Islands are quite different from those spoken in the Carolines (due to the influence of the island groups to the south and east), and the Caroline dialects differ considerably from those oft he Pelews and Yap, the latter islands being more influenced by the later Malays. Many natives throughout the islands speak English, having been taught by British and American whalers, traders and missionaries. It is probable that interpreters are plentiful; their loyalty depending upon the amount of their salaries.

The foreign population of the islands is probably about 2000 at the present time, this estimate including Japanese civilians but not troops.

The Economic Conditions

The general industries of the people include the cultivation of coconuts, bread-fruit, bananas, tare, yams, sugar cane, kava, etc.; the raising of goats and pigs and a few cattle (in the Western islands); and fishing. The chief families are the owners of the land, the ordinary natives being only tenants. The principal exports are copra, beche-de-mer (dried sea slugs) and tortoise-, turtle- and pearl-shell. The principal imports are cotton goods, canned food, sheet iron, cutlery, fishing tackle and novelties. The widespread and extensive fishing industry, together wit h general water transportation needs, has brought into being a vast "native merchant marine," composed of outrigger canoes and pram. In addition, there are a number of inter-island and ocean-going schooners (sail and power), owned by white and Japanese traders, plying among the islands. These schooners take care of the main export and import trade. At the present time the Japanese traders have practically a monopoly on the trade, the Japanese military government having imposed such restrictions upon foreign vessels as to make competition well-nigh impossible.

Trading headquarters are generally established in the main island of each group, together with substations on adjacent islands. Exports are more or less concentrated by the native craft and then picked up by schooners. Stores are maintained on board ships or on shore, where the bartering is done. The peonage system of credit prevails more or less. Practically all of this business is carried on by whites, Japanese and Chinese (storekeepers). Rough rock landing stages for light craft, and rough warehouses have been constructed at many of these trading stations.


There are certain trading steamers (mostly Japanese) which visit the islands, particularly Anguar Island in the Pelew group, which has a regular line of steamers plying for the removal of the phosphate deposits. The only cable communications are at Yap Island, which is connected with Guam, Japan and Menado (Celebes). There are, of course, military radio stations on several of the islands.

Health conditions are considered good, for the tropics. Fevers and catarrh are common in or near the swampy belts and areas of the volcanic islands during the rainy season. Consumption, ring-worm and elephantiasis are also quite common among the natives. Leprosy and venereal diseases are rare. Epidemics of measles and small-pox have visited the islands from time to time, with very deadly results. While the native population has decreased rapidly during recent years, it is believed to be holding its own at present.

The main factor in the preservation of the health of our troops would be their encampment under their own shelter on high, well-drained ground open to the winds, especially the cleansing north-east trades.

The Enemy

Japan is a World Power, and her army and navy will doubtless be up to date as to training and materiel. Considering our consistent policy of non-aggression, she will probably initiate the war; which will indicate that, in her own mind, she believes that, considering her natural defensive position, she has sufficient military strength to defeat our fleet.

As previously stated, upon our entry into the theatre of operations, the enemy will endeavor with his torpedo, mine and bomb craft to reduce our superiority in gun and torpedo ships. In support of these operations he will defend with all arms certain points as bases for his sea forces and will mine or garrison others. On account of the fact that the enemy's main hope of victory lies in the defeat of our fleet, it is to be presumed that he will use land forces freely in connection with his sea operations. By a universal shore resistance the enemy will not only complicate and delay the course of our operations, but will create unusual opportunities for his own attacks. The points of resistance will, of course, be those upon which his own ships are based and those which would be of the most value to us. It is not likely that he would, as a rule, strongly fortify atoll anchorages for his own use, except those of the volcanic type, which afford ample facilities for his light forces. The atoll anchorages, best adapted to fleet use, he would probably deny by land forces and mines: using them until reduced only as emergency refuges and fuel depots.


The Japanese have had a great deal of experience in offensive ship-shore operations, and have always done well. It is expected that they will do equally well on the defensive, and will have ample time, both before and after the beginning of hostilities, to plan and perfect any defenses they desire. They are cunning and resourceful, besides being good organizers--good qualities for the execution of the work in hand. They will have perfect knowledge of the land, sea and air in the theatre of operations.

Our advantages over the enemy will be those generally common to the Nordic races over the Oriental; higher individual intelligence, physique and endurance. These superior qualities will manifest themselves directly in our superiority in the use of hand weapons and in staying power. The Japanese sometimes reach a high peak of morale, but react quickly and, being excitable, they become rapidly disorganized - not only in defeat, but often in victory. The key of our tactics should therefore be to get his individual "goat" and keep it.


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