Visibility Exercise
You were using a ship sailing in formation as a marker to determine the visibility. After taking all the observations, you notice that the ship is no longer visible. What would you do about the observed visibility value? Choose the best answer.
The correct answer is c).
If other markers prevent you from determining whether the visibility lowered or the distance between the ships changed, you need to check whether the distance changed. If the distance increased, then it is likely that the visibility value did not change (unless there was extremely rapid fog development). If the distance remained the same, the visibility value needs to be lowered because the ship was visible at the start of the observations, but disappeared towards the end.