Final answer:
A man signaling with outstretched arms aboard a vessel is likely making a distress signal to attract attention for help. These hand signals play a critical role in maritime communication, particularly when other means are unavailable and can be crucial for survival and rescue efforts.
Step-by-step explanation:
A man aboard a vessel signaling by raising and lowering his outstretched arms to each side can be interpreted as making distress signals. These signals are a universal way of communicating the presence of trouble, particularly at sea, where traditional means of communication may not be available. The scenario described indicates that the men on the boat are in need of help, and they are attempting to attract attention from those on shore or elsewhere.
From the excerpts provided, we can infer that these men are being carried by currents, facing rough waves, and presenting a situation that requires the interpretation of visual communication. A person removing a coat and waving it, or someone signaling with outstretched arms, are forms of signaling distress or attempting to guide someone. Such signals serve the vital purpose of guiding rescue efforts or communicating the location of the vessel in distress, especially when verbal communication is not an option.
In maritime situations, different hand signals have different meanings, and these men might also be trying to direct the rescuers, indicating movements or actions they should take. They may also be attempting to indicate their own intentions or directions, especially in the absence of a working compass or other navigational tools.