What are current has the greatest effect on which type of boat?

Surface currents have the greatest effect on smaller boats, such as dinghies and kayaks, which are more susceptible to changes in water movement. These currents can significantly alter their course and speed, making navigation challenging. In contrast, larger vessels, like cargo ships, are less affected by surface currents due to their mass and propulsion systems, although they still need to consider currents for safe passage and fuel efficiency. Overall, the impact of currents varies by boat size and design.