Rubber Plan. The full title of the plan was the "Joint Basic Plan for the Occupation of Northern Brazil [Joint], Serial 737 of 21 December 1941". This was obviously something of a mouthful. Fortunately, the initial part of the plan, covering the amphibious operation that would seize several key ports and airports, had a snappier title, "Plan Rubber". The aim of Plan Rubber was to land US Marines in Brazil and on an outlying island to secure the vital airfields. The primary target was the airport at Natal, the primary airfield in the transatlantic link. Other mainland targets were São Salvador in the south and Belém in the north, and also Fernando de Noronha Island.All three of the mainland sites had airfields or airports capable of taking B17 bombers and large transport aircraft.
Fernando de Noronha Island had a smaller airfield, but this had been built and was operated by the Italian airline Ala Littoria. Its strategic location flanking the sea routes to Recife and São Salvador and the possibility of Axis aircraft using it as a staging post made the airfield a vital target. Two other targets were deemed a priority, namely the airfields at Fortalenza and Recife, but for reasons that will be explained later, they were not to be assaulted from the sea.
Unfortunately, geography was against the planners from the start. With the exception of São Salvador (which featured wide sandy beaches), the littorals around Natal, Belém and Fernando de Noronha were almost totally unsuited to amphibious operations. At Natal, the beaches were sandy and shallow (ideal in themselves for landing craft), but were screened by a treacherous reef that was gapped only in six places. Landing craft would have to be launched nearly 9 miles offshore because of the reef. Finding the six gaps was likely to be difficult enough. At Belém the situation was worse; the best beaches were several miles from the city and were separated from it by miles of impassable swamp.
Apart from the docks at Belém itself, the only suitable landing points were some suitable beaches closer to the city, but these could only be reached by landing craft, and this only after an 8 mile journey upriver, and were overlooked from the heights surrounding the city. If these heights were defended in any strength, the landings would be extremely hazardous. Finally, Fernando De Noronha Island had only a single beach that could be used, it was only 200 yards wide and was swept by a particularly severe swell. Even an unopposed landing would have been treacherous; if well-defended, the beach could become a bloody killing ground. Geography was also the reason why Fortalenza and Recife could not be taken from the sea; Fortalenza was surrounded by impassable terrain, whilst Recife was completely defended by reefs (the name Recife is derived from the Portuguese word for reef). Both would have to be secured by land offensives mounted from Natal after the initial landings.Despite the significant problems that the geography presented, planning went ahead.
The US Atlantic Fleet would provide cover to the assault force, as well as shore bombardment from the battleship USS Texas and air support form the carrier USS Ranger (which could have embarked USMC squadrons tasked with ground attack in addition to her naval aircraft). The 5th Marine Division and the 9th US Army Division were allocated to the plan and began training for the expected amphibious assaults. In January 1942, troops from the 1st US Infantry Division and the 1st Marine Division staged an exercise at Cape Henry, Virginia, in conditions that were more benign to those that could be expected at Recife.
The result was a disaster, with navigation from ship to shore a particular problem; troops became scattered all along the beaches, organisation broke down and control was lost. In the eyes of the umpiring staff, the assault was a total failure, despite a 4:1 advantage over the nominal defending force. What was worse, from the perspective of Plan Rubber, was that the boat crews involved in this debacle were the same ones earmarked for the landings in Brazil. However, the exercises did show up some significant weaknesses in the ability to land troops from ships and it is possible that some of these, having been identified, could have been overcome by the time Plan Rubber was executed.