What does two short blasts indicate when signaled by a vessel?

Two short blasts when signaled by a vessel indicate the intention to pass another vessel on the starboard side. This signaling is part of the broader set of navigation rules known as the "sound signals" used in the maritime context, which are designed to ensure safe navigation and communication between vessels to prevent collisions.

When a vessel intends to overtake or pass another, signaling with two short blasts clearly communicates this intention. It allows the other vessel to understand how to respond and adjust its position accordingly, promoting safety on the water. This practice is crucial especially in conditions where visibility may be low or where vessels are in close proximity to one another.

In the context of the other options, operating astern propulsion refers to a different signal, which would involve three short blasts. Coming to a stop and signaling for assistance also use different sound patterns, thus reinforcing that distinct sound signals represent specific actions or intentions on the water.