Nautical Question

[Ottiebow]

Two balls in a vertical line mean different things when used as a buoy topmark or on board a ship

Which two meanings are correct

A Preferred Channel
B Fairway
C Isolated danger
D Pilot Vessel
E Not under command
F Anchored

Any help would be much appreciated

[Lie-in King]

This is way beyond my knowledge, but if I've read the following correctly, I'd say E & F (?)

http://navruleshandbook.com/Rule27.html

[Buenchico]

C:
http://www.sailingissues.com/navcourse9.html

and E:
(As per Lie-in-King's link)

Chris

[Ottiebow]

thanks very much we thought it might be C and E