Here are some search patterns that you could use if a vessel or aircraft went down.
In any situation, think about this while doing a search
(1) what are you looking for? ship - Liferaft - man in the water.
With all of the above you must then take the following into consideration.
(a) The weather
(b) The strength of the tide
(c) The wave height
(d) The temperature of the water
with the above information and regarding the following, then think about this
Sea is like a mirror, then the searches can be pretty wide
Storms, large waves and strong tides, then the searches must be very tight
There are various searches that can be carried out, the following searches are recognised in the IMASAR Manual.
Expanded Square Search
Downwind for 1 miles, alter to starboard 90 degrees, go down this course for 1 mile,
Then
Alter 90 degrees to starboard and go down this course for 2 miles
Then
Alter 90 degrees to starboard and go down this course for 2 miles
Keep adding 1 mile ever time you alter to starboard
These distances are just for examples
Sector Search Pattern
Go Downwind for 1 mile,
alter 120 degrees to starboard, this course for 1 mile
then
Alter to starboard 120 degrees and go on this course for 2 miles going through datum
then
Alter to starboard 120 degrees for 1 mile
then
Alter to starboard 120 degrees for 2 miles going through datum
then
Alter to starboard 120 degrees for 1 mile
then
Alter 120 degrees to starboard for 1 mile back to datum
then go down the Blue track as follows
Alter 30 degrees to starboard for 1 mile
then go to the above and do the same again
then go down the Black tracks as follows
Alter 30 degrees to starboard for 1 mile
then go down the above and do the same again
These distances are just for examples
Parallel Search Pattern
With this search it can be done with 1 or more vessels
The main vessels starting the search are the two back arrows next to datum (Black square)
They will go up past datum and after a certain distance will turn away from each other at 90 degrees
then at very short distances on this track will turn and go parallel to each other on reciptical courses
they will do this until told to stop
Other vessels (Red arrows) will take the next berth alongside the main 2 search vessels and also turn away from each other
Williamson Turn
For this demonstation, assume your going Due North
Turn towards the side that the man fell overboard, (in this case he's fell over the starboard side)
Alter till you see 060 degrees on your compass
Alter hard to port till you see 200 degrees on your compass
Square up your helm to amidships, this will take you down on a reciptical course
