Found it!!
What I'm reading and understand is 9 (b) (i) All-round lights shall be so located as not to be obscured by masts, topmasts or structures within angular sectors of more than 6 degrees, EXCEPT anchor lights prescribed in rule 30, which need not be placed at an impracticable height above the hull. (ii) says that if it's impractible to comply that two all round lights are to be displayed to that they look as one from one mile away. (Paraphrased there). It makes it pretty apparent there that they do not want any angular voids in the lights while at anchor. Typical bureaucratic b/s. No wonder there are so many discussions and disagreements. The bottom line is that the mast head is the way to go. If you were sitting in a dark anchorage without a 360 degree light being shown and someone t-boned you claiming they didn't see you because they entered in the "6 degree" dark spot, I'm afraid the anchored boat would probably buy the violation of Rule 30. It's beer 30!!
What I'm reading and understand is 9 (b) (i) All-round lights shall be so located as not to be obscured by masts, topmasts or structures within angular sectors of more than 6 degrees, EXCEPT anchor lights prescribed in rule 30, which need not be placed at an impracticable height above the hull. (ii) says that if it's impractible to comply that two all round lights are to be displayed to that they look as one from one mile away. (Paraphrased there). It makes it pretty apparent there that they do not want any angular voids in the lights while at anchor. Typical bureaucratic b/s. No wonder there are so many discussions and disagreements. The bottom line is that the mast head is the way to go. If you were sitting in a dark anchorage without a 360 degree light being shown and someone t-boned you claiming they didn't see you because they entered in the "6 degree" dark spot, I'm afraid the anchored boat would probably buy the violation of Rule 30. It's beer 30!!