Which of the following is a method of internal communications on a ship?

Sound powered phones are indeed a method of internal communications on a ship. They are designed to facilitate communication between crew members, typically in high-noise environments where other forms of communication may not be effective or possible. These phones do not require an external power source; instead, they operate based on the principle that human voice produces enough sound energy to operate the equipment.

Visual communications might include flags or lights, which are more typically used for external communications or signaling with other vessels rather than for internal ship communications. Radio transmissions and satellite communications generally involve external communication channels and are not the primary methods used for communicating among the ship's crew.

Thus, sound powered phones are a reliable, efficient means for the internal communication needs of a vessel.