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USCG Exam Practice · Rule 27 — NUC and RAM (lights)

A vessel engaged in mine clearance operations exhibits three all-round green lights. What does this signal indicate to other mariners?

  1. AThe vessel is restricted in her ability to maneuver and has an obstruction on both sides
  2. BIt is dangerous for another vessel to approach within 1000 meters of the mine clearance vessel✓ correct
  3. CThe vessel is not under command and requires assistance
  4. DThe vessel is engaged in underwater operations with a diver deployed

Why B is correct

33 CFR §83.27(f) states that the three all-round green lights (or three balls) exhibited by a mine clearance vessel indicate that it is dangerous for another vessel to approach within 1000 meters of that vessel. These lights are in addition to, not instead of, the vessel's normal underway or anchor lights.

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A vessel engaged in mine clearance operations exhibits three all-ro… — USCG Exam Practice · CaptainsGround