At Anchor - one ball

Not Under Command - e.g., engine off - two balls.

Aground - three balls - keep clear.

Restricted in ability to manoeuvre - ball, diamond, ball - e.g., pipe laying or divers down.

Obstruction - e.g. dredging - pass on the side with the diamonds.

Dive Boats - boats too small to show the bigger signals show the "A" flag.

Constrained by its draft - give room.

Mine Sweeper - Keep Away! - at least 1000 metres.