🔍 Key Concepts
• Rule 30 – Anchored Vessels and Vessels Aground (Navigation Rules)
• Day shapes for vessels aground versus restricted in ability to maneuver (RAM) and towing
• How many shapes are displayed, and in what pattern (vertical line, triangle, single shape, etc.)
💭 Think About
• First, recall exactly what day shapes a vessel aground must display. How many shapes are there, what are they, and how are they arranged?
• Next, think about each listed vessel type and recall its normal day shapes: does it use the same number of shapes in a straight vertical line, or a different pattern?
• Ask yourself whether any of the listed vessels uses a vertical string of the same shapes, or whether they use combinations (like ball–diamond–ball) or different arrangements.
✅ Before You Answer
• Verify from Rule 30 what the day shape for a vessel aground is (number of balls and their arrangement).
• For towing a submerged object, verify whether the shape is a ball, a diamond, or a combination – and how many.
• For dredging or hydrographic survey vessels, confirm if they are treated as restricted in ability to maneuver (RAM) and what that RAM day shape pattern is (ball–diamond–ball or something else).