If you are in restricted visibility, what should you do after stopping your engines while sounding a long blast?

In restricted visibility, the appropriate action to take after stopping your engines while sounding a long blast is to change to two long blasts every two minutes. This practice is outlined in the COLREGs, particularly Rule 35, which states that a power-driven vessel shall sound one prolonged blast to indicate its presence when at anchor. However, when you're not navigating, it's crucial to continue signaling your position to enhance safety and prevent collisions.

By adopting the practice of two long blasts every two minutes, you are effectively communicating your situation to nearby vessels, indicating that you are still present and aware of your surroundings. This is particularly important in restricted visibility, where vessels may be unable to see each other clearly.

The other options do not provide the necessary communication effectiveness or safety measures required in such conditions. For instance, stopping all sound signals immediately would eliminate your means of notifying other vessels of your presence, which increases the risk of collision. Continuing with one long blast does not comply with the stipulated signaling practice during periods of the vessel at anchor with engines stopped, and resuming engine operations without proper assessment could lead to confusion among other nearby vessels regarding your intentions. Thus, changing to two long blasts every two minutes is the correct and recommended action in this situation.