the avisos of the Afonso de Albuquerque class. To avoid being confused with ships from belligerent countries, the Portuguese merchant vessels started to navigate with large flags of Portugal and their names painted on the sides of the hull. However, this did not completely prevent some submarine attacks against Portuguese ships. The most serious attack would occur in 1942, when the three-masted lugger sailing ship Maria da Glória, navigating en route to Greenland, was attacked and sunk by the , with the death of 36 of her 44 crew. A particular concern was the defense of the strategic Atlantic islands of the Azores against a possible invasion. In 1941, islands began to be strongly reinforced with ground and air forces, with a garrison of 32,500 troops and more than 60 aircraft. The Portuguese Navy focused in the defense of the waters and ports of the Azores with patrol boats and destroyers deployed on rotation. These surface forces were supported by Fleet 10, Avro 626, Grumman G-21 and Grumman G-44 seaplanes that patrolled the waters from the reactivated Azores Naval Air Station at Ponta Delgada. In a smaller scale, similar reinforcements were also sent to Madeira and to Cape Verde islands. Although both the Axis and the Allied powers had plans to invade the islands and use them to control the Atlantic (including the planned British operations Alloy, Shrapnell, Brisk, Thruster, Springboard and Lifebelt, the US Operation Grey and the German operations Felix, Ilona and Isabella), the Portuguese military reinforcements were able to support Portuguese diplomacy in successfully deterring any attempt at performing that invasion. The Navy also had to plan a possible strategic evacuation of the Portuguese Government to the Azores. This evacuation was planned to occur in the case of an enemy invasion and successfully occupation of Continental Portugal. The risk of this invasion happening was considered high and plans for it were in fact included in the German preparations for the planned operations Isabella and Felix. An effort was also made to defend the Portuguese overseas territories in Africa, Asia and Oceania. Although the naval and military assets were always few for such large number of territories, it was still possible to maintain the integrity of the great majority of them. The major exception being Portuguese Timor, which was occupied by Australian and Dutch forces in December 1941, allegedly to defend it against a possible Japanese invasion. After