🔍 Key Concepts

• Inland Rule 27 – lights and shapes for vessels restricted in their ability to maneuver, including dredges and pipeline operations • Meaning of red vs. green fixed lights on dredging or obstruction work: which side is safe to pass and which side is obstructed? • Purpose of yellow pipeline lights along the bottom of the illustration and how they relate to where you should NOT take your vessel

💭 Think About

• Look carefully at where the red pairs of lights are located versus the green pair of lights. Do red lights on dredging/pipeline work usually mark the safe side or the obstructed side? • Trace an imaginary track for your vessel from left to right. Which of the labeled routes (A, B, C, or D) actually keeps you on the side indicated by the green lights and clear of the pipeline marked by yellow? • Think about whether these lights are traffic-control signals that will change (like red-to-green), or fixed marks that tell you where the obstruction is and where the safe water is, regardless of your arrival time.

✅ Before You Answer

• Verify in Rule 27 (Inland) that two red lights in a vertical line on a dredge mark the obstructed side of the dredge or work area. • Verify that two green lights in a vertical line mark the safe side for passing the dredge or obstruction. • Confirm whether waiting for the red lights to change color is ever described in the regulations for dredging or pipeline-light configurations (are they signals that change, or fixed obstruction marks?).