Questões de Concurso Militar DPC - Marinha 2008 para Praticante de Prático

No que se refere a aparelhos de laborar, a talha singela é um dos tipos mais aplicados a bordo para serviços gerais do convés. Pode ser descrita como:

De acordo com o livro “Navegação: A Ciência e a Arte”, de A. P. Miguens, com referência aos controles operacionais do radar, quando se deseja melhorar a imagem do radar pela supressão dos ecos produzidos pelo retorno do mar nas proximidades do navio, o operador faz os ajustes necessários por meio: 

According to Swift & Bailey, in the book “Bridge Team Management”, the plan of the passage having been made, discussed and approved, execution of the plan now has to be determined. By this is meant the methods used to carry out the plan, including the best use of available resources. Final details will need to be confirmed when the actual timing of the passage can be established. It must always be borne in mind that safe execution of the passage may only be achieved by: 

Um navio está navegando em um canal restrito em profundidade e largura. Sabe-se que a profundidade e a largura do canal são uniformes. Seu rumo é paralelo ao eixo central do canal, mas o navio está navegando a bombordo desse eixo. Quais serão as tendências do navio, de acordo com o livro “Principles of Naval Arquitecture” (PNA)?

Before starting to practice in order to improve his ability to estimate his ship’s speed with accuracy, an inexperienced shiphandler studied the methods available by which the mariner can judge speed. During the study, he made a list with the following notes:
I) Doppler speed indicator showing lateral motion as well as ahead and stern speed is a valuable shiphandling tool, especially when moving larger ships where speed is critical and tolerance for error small.
II) fixes by radar or visual bearings are convenient and sufficiently accurate for determining speed in a docking situation.
III) even at night is better to estimate ship’s speed looking at objects abeam or little abaft than looking objects ahead of the ships.
IV) if the ship’s quickwater falls behind the ship when the engine is put astern, the vessel’s speed is 3 knots or more.

According to MacElrevey & MacElrevey, in the book “Shiphandler for the Mariner”, what is the correct alternative?