What is a common indicator that boat bottom paint is wearing off?

The presence of increased biofouling on the hull is a common indicator that boat bottom paint is wearing off. Bottom paint, also known as antifouling paint, is specifically designed to prevent marine growth such as algae, barnacles, and other organisms from attaching to the hull of the boat. When this protective coating begins to wear away, it becomes less effective at inhibiting biofouling, leading to an increase in marine growth on the surface of the hull. This not only affects the aesthetic appearance but can also reduce the boat's performance, including speed and fuel efficiency, as the additional drag from biofouling impacts hydrodynamics.

In contrast, an increase in fuel efficiency, the boat becoming lighter, or a smoother ride on water are not associated with wearing off paint. When bottom paint deteriorates, it typically leads to the opposite effects: reduced fuel efficiency and a potentially rougher ride due to increased drag from biofouling.