In the theatre of Mozambique, the main operational focus of the Portuguese Navy was the Lake Nyasa, in an effort to deter FRELIMO forces infiltrations from their bases in Tanzania and to cooperate with the Military of Malawi. This mission was done by the Nyasa Flotilla, operating mainly from the Metangula naval base, and by units of marines. The establishment of the Nyasa Flotilla was possible by the organization of complex logistical operations to transport a total of 12 patrol and landing craft from the coastal port of Nacala to Lake Nyasa, in a route of about 750 km by land. In the scope of the cooperation with the neighbor Malawi, the Portuguese Navy was deeply involved in the organization of its naval forces, transferring to them some of the Nyassa Flotilla boats. The Navy also focused in the resupply of the Portuguese Forces operating in Northern Mozambique, connecting them, by sea, with the main logistical centers in Lourenço Marques and Beira. With the beginning of the construction of the Cahora Bassa Dam and the spread of the FRELIMO guerrillas to the Tete region, in the early 1970s, the Navy oriented part of its effort to the Zambezi River.