The Coco River Patrols
By Capt Jon T. Hoffman - Originally Published September 1990
Marines reflecting on the merits of light infantry can find some informative examples to analyze in their own rich history.
Merritt A. Edson earned his reputation as the Corps' quintessential light fighter during the U.S. intervention in Nicaragua between the world wars. The newly promoted captain arrived in that country in February 1928 at the head of the USS Denver's 56-man Marine detachment. As part of the effort to quell Augusto Sandino's rebellion, he and his men made three separate forays up the Coco River during their 13 months ashore.
The initial effort was a daring reconnaissance patrol by Edson and 5 men that penetrated 260 miles along the major water route between the coast and the rebel-dominated central highlands. The second operation followed quickly on the heels of the first after Sandino's guerrillas attacked American-owned mines In the interior. Over the course of an 8-week period Edson's unit covered about 1,000 miles by boat and on foot, but it was never able to catch its quarry.
The small detachment had barely begun a period of hard-earned recuperation when Brigade headquarters' launched it yet again (with reinforcements from the Cohesion) in an effort to finally destroy Sandino and his band. Edson was chosen for the mission because of his demonstrated aggressiveness and his eagerness to penetrate the most difficult terrain. This third Coco Patrol got underway in July 1928; it would not return to the coast until March of the following year For much of this period the unit operated from a primitive patrol base deep in the wilderness at the junction of the Coco and Poteca Rivers.
One of the greatest challenges that Edson and his men faced was simply feeding themselves, The rare villages, generally of a few dozen inhabitants or less, wore unable to provide much, and Edson knew that each stop was an intelligence coup for the enemy. Mules helped, but their range was limited to short patrols they could not transport supplies hundreds of miles from the coast to the interior. Boats were another alternative with limitations. In tactical use they constrained operations, since patrols were limited to what they could carry on their backs once they left the waterways and moved overland. They were more effective in making logistics runs to the rear, though portages slowed movement and rough water caused substantial losses. Marine aviation proved to be the most reliable and rapid form of support, but the meager capacity of existing aircraft could not keep up with demand. The land itself yielded little to forage upon, though the Marines occasionally found some wild bananas or snared a monkey.
The difficulty of procuring food drove the patrol to extreme lengths. During most operations Edson allowed the men to consume just two scant meals a day in order to stretch out meager stocks. At one point the Marines ate kerosene-soaked rice, the result of a mule accident, because the alternative was nothing at all.
The shortages went beyond food, of course, to everything that the patrol required, from ammunition to radio batteries, Even simple things like socks became a precious commodity. The day after Edson's largest battle with Sandino, he evacuated three wounded men and a fourth due to foot problems. In a message just two days later he saw his "biggest difficulty" as "sore feet" and urgently demanded a resupply of shoes and six pairs of socks per man; in an earlier communication he had described foot problems as "epidemic." With just 41 men in the field at the time, he could ill afford even minor losses to maladies that could have been avoided with good supply lines.
Illness and privation frequently had pther effects on the patrol's ability to fight. Edson later recounted one such instance in detail. During a particularly difficult movement the captain carried the pack of a man suffering from malaria. Finally, the Marine refused to go further. When blandishments failed, Edson led the rest of the patrol away ''Realizing then that I was not bluffing, he decided that perhaps he, too, could manage to go along. But the rate of march was slowed down for the rest of the day." At one point early in the stay at the Poteca patrol base, the unit had 14 men on the sick list, 3 of whom had to be evacuated soon thereafter.
The deprivations eventually shook even the strict Marine discipline of the time. In one case four privates deserted the unit, stole a native craft, and headed downriver. They surrendered a day later at an outpost, after their boat overturned in rapids, but their foray revealed the level of desperation among at least some of the men. Edson ascribed their actions to "lack of adequate rations," which did not deter him from ordering a court-martial for the offenders. Another private attempted the same feat five months later, and the records attest to occasional absences from the camp to avoid patrol duty. Similar incidents happened in other remote posts. Conditions were extremely hard in the field and some men just could not stand up to them.
The failure of another Marine patrol in the area highlighted the difficulties which light infantry had to face. At the end of three weeks, 1 man drowned and 36 of the remaining 46 men in the unit were incapacitated due to injury or illness. A fresh patrol had to be dispatched to evacuate those who could not continue. The unit never made contact with the enemy, but the northern area commander later recommended six of the men for the Navy Cross for courage in their battle against nature.
Logistics requirements often drove tactical decisions. Edson fought hard to increase aerial resupply efforts so that he could concentrate on offensive operations rather than guarding his supply lines, but Brigade never diverted sufficient assets to his operation. He therefore reluctantly established the Poteca patrol base in order to maintain a logistics depot and relied on small units operating from that facility to track down the enemy. The results were poor, and he continued to press higher headquarters for a freer hand, so that he could end guerrilla occupation of the "no man's land" in the torturous terrain where the three geographic commands came together:
My idea is the organization of a patrol of about 40-50 men, with no fixed limits of patrolling, free to move in this territory as outlined, following such clues as it can pick up and reporting in at the neatest post in any one of the three areas for rations about once every fifteen days . . . a continuous roving patrol. The idea would be an outfit as near like the bandits as possible-using the side trails they use-becoming bush men like them-and living like them. This patrol would have no regular base to return to every ten to twenty days-but would probably reach its original supply base once a month or every six weeks . . . This would be damned strenuous work-it would require an outfit of 100 men, for this kind of patrolling would wear out half the command a month, and it might not bring any belter results than we have had already. But I would certainly like to give it a try. Even tho it by itself gets no contact with the outlaws, I believe that a roving band of this kind would be quite likely to chase them into the hands of some other patrol with equally as good results.
Brigade belatedly adopted Edson's idea in March 1929 but allowed him only a very limited opportunity to put it into execution. With the American withdrawal from Nicaragua already underway, he would have just three weeks for a roving operation before returning his unit to the coast and the Denver. The patrol eventually did make contact with a rebel band, but in the ensuing firefight two Marines were hit. Edson led part of his men in pursuit, but had to break it off after two hours and return for his casualties before nightfall. The cost of killing two guerrillas was one Marine dead and another wounded. The patrol put both men in litters' and headed for the nearest base.
Edson's last, report described the tactics which he had faced over the past few months. The ambush was no longer the opening move of a battle, but a means to harass the patrol, inflict a few casualties, slow the Marine advance, and protect the rebel main body. He thought the only answer was for a unit to split in two at the end of an ambush, with one element pursuing the guerrillas while the other looked after the pack train and casualties. But, as the just-completed operation had demonstrated, even that response had its limitations; wounded men needed medical attention that a small patrol simply could not provide.
The legacy of these operations does not stem so much from hard-fought battles against a tough foe, though there were numerous combat actions. It is more a tale of courage in a struggle against nature and nearly nonexistent support. Edson himself later incorporated the resulting lessons on logistics, leadership, and tactics into the Small Wars Manual. The story of the Coco Patrols is thus one that should be of great interest to modern Marines thinking about light infantry doctrine.