Manoverboard occurs when a person falls in the water while working, being washed by big waves, or because of a simple slip at the side of the ship. Time is of great essence for the crew to respond because the victim may be injured or will most likely suffer from hypothermia due to long exposure to cold water.
Williamson, Anderson, and Scharnov’s turn allow the vessel to maneuver depending on different scenarios. This would depend if the victim just fell and the ship would need an immediate response. A different maneuver is required if the incident occurred hours earlier. Another turn is for either daytime or nighttime search or for sector search and rescue.
The vessel is turned differently depending on the situation. It is very important for the officer of the watch to be familiar with the principles of each maneuver as the safety and recovery of the victim would depend on how quick and efficient the search and rescue operation is.
To let crewmembers react quickly and use proper maneuvers depending on the prevailing circumstances shipmasters and managing companies include Man Over Board (MOB) drill to a list of regular drills onboard merchant vessels.
The Williamson Turn
This maneuver is recommended for nighttime search and rescue and reduced visibility situations. It allows the vessel to return to its previous position if the victim is out of sight but within the range of 15-20 nautical miles.
As soon as the officer of the watch is informed that a person has fallen overboard, he immediately puts the steering in manual mode from autopilot as well as informs the engine room to put the engine on standby. He commands the helmsman to put the rudder hard over to the appropriate side.
As the ship’s heading reaches more than sixty degrees from the original course, the wheel is directed in opposite direction hard over. This is done until the vessel reaches a reciprocal course and the engine is adjusted as needed. As soon as the correct course is attained, the officer on watch places a lookout for the victim. Ideally, the victim is placed on the starboard bow of the ship.
The Anderson Turn
The Anderson turn is also known as the Single turn and is the quickest maneuver to the location of the fallen victim and is recommended if the man overboard is still visible or on sight. It also brings the vessel back to its wake or trails.
This is the quickest maneuver to the casualty. The Officer of the watch places a lookout to keep the victim in sight at the same time that he releases the MOB signal located at the bridge wing. The steering is put to manual mode and the engine is on standby.
The rudder is put hard over to the side of the fallen person. The vessel deviates 250 degrees from the original course to make the Anderson turn. The OOW maintains speed during the turn while stopping the vessel when the victim is 15 degrees off the bow. OOW checks the wind and current during recovery and that casualty does not reach the propeller.
The Scharnov Turn
Scharnov’s turn is not recommended for an immediate maneuver if the victim is still in sight. This turn allows the vessel to back to its previous trial and wake. However, it cannot be carried out effectively unless the time elapsed between the incident happened and the commencement of the maneuver is known.
The steering is taken off autopilot and put hard over to the side of the fallen crew. As soon as the course/heading deviates about 240 degrees from the original course, the rudder is put to the opposite side. As the heading approaches 20 degrees short of the original course, the wheel is put to midships.
Speed is adjusted as the vessel approaches the man overboard while other teams prepare the rescue boat to be launched. The officer of the watch considers wind and current in the recovery of the victim.