Object is to determine how far your vessel is offshore.
|Relative bearings are measured from the vessel’s bow clockwise; dead ahead = 000°R or 360°R; dead astern = 180°R.
||Relative bearing can be eyeballed by ADDING the desired bearing (say 45°R) to the vessel’s compass course ( say 105°C) and sight over the vessel’s compass for an object at 150°C.
||Note the time the object is sighted at the relative bearing.
||When the same object is sighted at twice the relative bearing (say 90°R) or 195° Compass, note the time.
||Calculate Speed-Distance-Time problem: (See Speed/Distance/Time page)
- Speed = boat speed, known (example=12kts)
- Time = difference between first and second bearings (example: Time1=0900; Time2=0915)
- Distance: will equal the distance off the object when you arrive at second bearing