A vessel engaged in mineclearance operations shall, in addition to the lights prescribed for a power-driven vessel in Rule
23 or to the lights or shape prescribed for a vessel at anchor in Rule
30, as appropriate, exhibit three all-round green lights or three balls. One of these lights or shapes shall be exhibited near the foremast head and one at each end of the fore yard. These lights or shapes indicate that it is dangerous for another vessel to approach within 1,000 meters of the mineclearance vessel.