In discussing the navigational requirements for any vessel (including yachts) it must be remembered that there are two co-related areas for discussion: equipment and knowledge. Of these two the requirement for knowledge is of greater importance. Knowledge implies the ability to use the apparatus at one's disposal to the maximum efficiency in order to obtain the information one requires and, of equal importance, the ability to assess the validity of the information so obtained, and thereafter to use it in the most beneficial manner in the prevailing circumstances.