Monday, October 10, 2011

Use of the GPS to regain the track-line to recover a MOB

Typical Maine GPS

In the case of a crew (man) overboard many  GPS units have a MOB (man overboard) button which will give the bearing and range back to the position of the ship when the button was pushed. The problem is  the button may be overlooked  entirely or it may not pushed in a timely manner.  Even if it is pushed in a relatively timely manner it may be difficult to determine the distance between the MOB position on the GPS and the actual position of the crew in the water.

However,   the crew member in the water has to be somewhere along the previous track. This track  information is likely stored continuously and automatically on the GPS unit.

The GPS "PLOT", which shows the previous track, can be an invaluable aid in locating the ship's track while executing the man overboard turn.

It is important to know how to switch to the PLOT screen during the overboard emergency  and it is also important to check to insure that it is set up properly to continuously record the ship's track before the emergency.

The ship's track may also be stored in other electronic equipment. For example  "target trails" on the radar set at the appropriate time may also display the ship's previous track.


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