What are different search patterns as per IAMSAR ?

SECTOR SEARCH (V5)

• Most effective when the position of the search object is accurately known and the search area is small.
• Used to search a circular area centred on a datum point.
• Due to the small area involved, this procedure must not be used simultaneously by multiple aircraft at similar altitudes or by multiple vessels.
• An aircraft and a vessel may be used together to perform independent sector searches of the same area.
• A suitable marker (for example, a smoke float or a radio beacon) may be dropped at the datum position and used as a reference or navigational aid marking the centre of the pattern.
• For aircraft, the search pattern radius is usually between 5 NM and 20 NM.
• For vessels, the search pattern radius is usually between 2 NM and 5 NM, and each turn is 120˚, normally turned to starboard.