What does the combination of red and green lights typically suggest?

The combination of red and green lights typically indicates that you are approaching a sailing vessel. According to maritime navigation rules, these colored lights are used to signal the presence and direction of different types of vessels. A red light is displayed on the port (left) side of a vessel while a green light is on the starboard (right) side. When a vessel is underway, seeing both red and green lights means that you are likely to be seeing the bow of a sailing vessel, which is an important navigational signal to be aware of.

The other answer choices focus on different types of vessels or situations, which is not what the combination of red and green lights specifically indicates. For instance, narrowing it down to encountering a fishing vessel or a recreational boat does not pertain to the general navigation lights used, as these vessels may display different lighting patterns that do not include both red and green lights seen together. Similarly, nearing the shore doesn't typically involve specific light signals that convey the type of vessels in the vicinity. Understanding this lighting system is crucial for safety and effective navigation on the water.