What color channel marker indicates to return to harbor?

The correct answer is red, which is vital for indicating the safe return to harbor. In the system of navigation aids used in the U.S. and many other regions, red markers are utilized to signify the right side of a channel when entering from the open sea. This is part of the "IALA system" (International Association of Lighthouse Authorities) that helps boaters navigate safely.

When a mariner is returning to harbor, they must keep red markers to their right side, which not only aids in ensuring a safe passage but also assists in understanding which direction they should be traveling. Knowing this is essential for avoiding navigational hazards and successfully approaching a port or harbor.

The other colors listed serve different navigational purposes: green markers indicate the left side of the channel when entering, blue markers are typically used for informational signs or mooring areas, and yellow does not have a standardized meaning in channel navigation. Understanding the significance of these markers helps in safe boating practices.