Which publication is known for tactical communications among Allied naval units?

The publication known for tactical communications among Allied naval units is the Allied Tactical Publication. This document standardizes communications, procedures, and tactics for forces from different nations, facilitating interoperability during joint operations. It encompasses various aspects of naval warfare, including signaling protocols and operational concepts specifically tailored for collaborative efforts.

The other options serve different purposes: the American Practical Navigator is a comprehensive guide on navigation and not focused on tactical communication; the Nautical Almanac provides essential data for celestial navigation and astronomy; while the World Port Index includes information on ports worldwide but does not address tactical communication. This distinction highlights why the Allied Tactical Publication is the correct choice for facilitating communication in a joint military environment.