The marker is only one part of the repair
A navigational buoy has to stay in a known place and remain visible to mariners. If a collision, storm, or other force damages it, the problem may extend below the surface: its anchoring gear can shift or fail, and its light or other equipment may need attention too. Replacing the floating body alone does not necessarily restore a reliable aid to navigation.
That makes the job different from swapping out an ordinary sign. A crew may need a vessel capable of carrying equipment and handling the buoy, plus divers to inspect or work on submerged components. The vessel and specialists must reach the site together, often doing work that cannot be completed from shore.
Why the labor can outweigh the hardware
Much of the expense is tied to assembling and sending a capable crew, not simply buying a new marker. Vessel time, skilled labor, equipment, and travel all cost money even when the damaged part itself is relatively straightforward to replace. The farther or harder a site is to reach, the more consequential that mobilization can become.
Repair crews also have to determine what is actually damaged. If the mooring has moved or underwater parts need inspection, a quick surface fix could leave the buoy in the wrong position or unable to stay there. The choice is therefore not always “repair the buoy” versus “buy another one”; it may be whether the whole aid can be made dependable with the work available.
A small object, a larger operating cost
For the organization responsible for the marker, the practical comparison is between the cost and reliability of repair and the cost of replacing the system and returning it to service. That is why a buoy that looks like a single object from a passing boat can require a substantial operation: the expensive part may be getting the right people and vessel to the right place, not the buoy itself.
