The first crewmember to observe a person overboard should give the alarm by yelling "man ___________________".

The correct wording for the alarm is "man overboard." This phrase is universally recognized in maritime operations and serves as an immediate call to action. When a crew member identifies that someone has fallen overboard, their primary responsibility is to alert the rest of the crew quickly and clearly. The specific phrasal construction "man overboard" effectively communicates the seriousness of the situation without ambiguity, ensuring that all crew members understand the need to respond quickly. This phrase initiates emergency protocols, including stopping the boat, launching a rescue operation, and maintaining visual contact with the person in the water.

Using alternative phrases, such as "man over" or "man down," may not convey the urgency or clarity required in this critical situation. "Man overboard now" adds urgency but may not align with standard emergency protocols and practices typically used in the maritime environment. It is important for crew members to use the universally accepted terminology to ensure instant recognition and response.