could give a proportionately higher contribution to the Portuguese war effort. Guinea is crossed by a multitude of water streams, many of them navigable rivers, and a large part of its territory is marshy and flooded. This conditions allowed the Portuguese Navy to intervene in virtually all the territory, including in its hinterland regions. By the other side, in this theater, the Portuguese forces faced the PAIGC, probably the best organized, trained and equipped of the independence movements, that from a certain point, managed to obtain a combat potential often equivalent or even superior to that of the Portuguese, which led to the conflict take on many characteristics of a conventional and no longer a mere guerrilla warfare. The PAIGC was even able to create its own Navy, equipped with some Eastern Bloc and Chinese naval assets, including modern P 6-class torpedo boats that constituted an additional threat to be faced by the Portuguese naval forces. Besides this, the PAIGC benefited from the support of the neighboring countries of Senegal and specially, of the Republic of Guinea. Given the relatively small land area of the Portuguese Guinea, the sanctuaries offered by those countries allowed PAIGC forces to be able to launch direct attacks against the Portuguese garrisons from their bases in those countries and quickly withdraw to the other side of the border before being hit by the Portuguese counter-strikes. In this theater, the Portuguese Navy played the most varied missions, including most of the logistical support to the Portuguese military units scattered throughout the territory, fire support to the land forces, amphibious assaults with Marine units and the interdiction of the water supply lines used by the PAIGC. The Portuguese naval presence in Guinea, from 1964, included a frigate, seven patrol boats, 15 landing craft, four Special Marine detachments and two Marine companies. Latter, additional landing craft and a Sapper Divers unit would be added, this latter to face the use of naval mines by the PAIGC forces. In 1971, in the scope of the "Africanization" policy of General Spínola, two African Special Marines detachments were created, staffed with personnel recruited locally in the Portuguese Guinea. To expel the PAIGC forces that were occupying the Como island and other near islands in the southern region of the Portuguese Guinea, in January 1964, the Portuguese Armed Forces launch the Operation Trident, a major conventional type joint operation, on which, for