The Williamson turn, the Anderson turn and the Scharnow turn are the three standard ship maneuvers for returning to a person who has fallen overboard. Each suits a different situation, depending on whether the casualty is still in sight and how long ago they went over the side. People go overboard while working on deck, when washed off by heavy seas, or after a simple slip.
This guide is written for officers of the watch and deck cadets. It sets out the immediate actions and the rudder orders for each turn. It also explains how to choose between them using the IAMSAR Manual’s three man overboard (MOB) situations.
What Are the Three Man Overboard Turns?
The Williamson turn returns a ship to its own track on a reciprocal course. The Anderson (single) turn is fastest when the casualty is visible. The Scharnow turn returns the ship into its wake after a delay.
All three are illustrated in IAMSAR Manual Volume III (Mobile Facilities), which every SOLAS ship carries on the bridge. The Scharnow turn is often misspelled “Scharnov” or “Sharnov”; the IAMSAR spelling is Scharnow.
What Should the Officer of the Watch Do First?
The OOW releases a lifebuoy, marks the position, raises the alarm and starts the turn towards the side the person fell. Every second counts, because cold shock and hypothermia leave a casualty very little time in the water.
- Release the bridge-wing lifebuoy on the side of the casualty. SOLAS Chapter III Regulation 7 requires at least two lifebuoys with self-activating smoke signals and lights that can be quick-released from the bridge.
- Mark the position with the MOB function on the GPS or ECDIS, and note the time.
- Put the rudder hard over towards the side the person fell, which swings the stern and propeller away from them.
- Raise the alarm with the ship’s MOB signal from the muster list, and hoist International Code flag “O” by day.
- Change to hand steering, put the engine on standby and call the master.
- Post lookouts who keep pointing at the casualty and never take their eyes off them.
- Alert other ships and the RCC by VHF and DSC through the ship’s GMDSS equipment, and prepare the rescue boat crew.
These duties belong to the officer keeping the bridge navigational watch until the master takes the con. Most companies post them as an MOB checklist in the wheelhouse.
Which Turn Should You Use for Each MOB Situation?
IAMSAR Volume III divides MOB cases into immediate action, delayed action and person missing. The Anderson or Williamson turn fits immediate action, while the Williamson or Scharnow turn fits a delayed or missing-person case.
- Immediate action: the person is seen going over the side from the bridge, or reported at once. Use the Anderson turn if they stay in sight, or the Williamson turn in darkness or poor visibility.
- Delayed action: someone else sees the fall and reports it after a short delay. Use the Williamson or Scharnow turn to get back onto the track line.
- Person missing: a crew member is reported missing, with no witness and no known time. Use the Scharnow or Williamson turn to search back along the reciprocal of the track.
Visibility, sea state, the ship’s turning characteristics and the time elapsed all shape the final choice. The master or OOW decides, but the decision is quicker if the options have been practised in drills.
How Is the Williamson Turn Performed?
The Williamson turn uses a hard-over rudder until the heading has changed 60°, then hard over the other way. The ship steadies on the reciprocal course and runs back down its original track.
- Put the rudder hard over. In an immediate action case, turn towards the side of the casualty.
- When the heading is 60° off the original course, put the rudder hard over to the opposite side.
- When the heading is 20° short of the reciprocal course, put the rudder midships and let the ship settle on the reciprocal.
- Reduce speed, keep lookouts on the bow and stop the engine as the casualty comes close.
The 60° figure is a guide for an average merchant ship. The best changeover point varies with hull form, loading and speed, so each ship should confirm it during sea trials or drills.
Advantages and Disadvantages of the Williamson Turn
- Advantage: the ship ends up on a reciprocal course, almost exactly on its original track line. This is its main value at night or in fog, when the casualty cannot be seen.
- Advantage: it is simple to perform and works in all three MOB situations.
- Disadvantage: it carries the ship further from the casualty than the Anderson turn, so the return takes longer.
- Disadvantage: it is slow for a large, deep-loaded ship with a wide turning circle.
The maneuver is named after John Williamson of the US Naval Reserve, who used it in 1943 to recover a man overboard. A similar turn had been used earlier in the Russian Navy, where it was attributed to Admiral Butakov.
How Is the Anderson Turn Performed?
The Anderson turn, called the single turn in IAMSAR, keeps the rudder hard over towards the casualty through about 250° of heading change. The ship then stops close to the person without ever steadying on a reciprocal course.
- Put the rudder hard over towards the side of the casualty.
- Keep the turn going until the heading has changed about 250° from the original course.
- Put the rudder midships and begin the stopping maneuver, aiming to stop with the casualty about 15° on the bow.
- Watch wind and current during the final approach, and keep the casualty well clear of the propeller.
Advantages and Disadvantages of the Anderson Turn
- Advantage: it is the fastest way back to a casualty who is still in sight.
- Advantage: it suits ships with a tight turning circle and plenty of power, such as twin-screw ships and smaller vessels.
- Disadvantage: the final approach is not straight, which makes it hard to judge on a large single-screw ship.
- Disadvantage: it does not bring the ship back onto its track, so it is of little use once the casualty is out of sight.
How Is the Scharnow Turn Performed?
The Scharnow turn holds the rudder hard over through 240° of heading change, then reverses it until the ship is 20° short of the reciprocal. The ship comes back into its own wake in less distance than a Williamson turn.
- Put the rudder hard over. In a delayed or missing-person case, either side can be used.
- When the heading is 240° off the original course, put the rudder hard over to the opposite side.
- When the heading is 20° short of the reciprocal course, put the rudder midships so the ship settles into its own wake.
- Adjust speed for the search while the rescue boat crew prepares, allowing for wind and current drift.
Advantages and Disadvantages of the Scharnow Turn
- Advantage: it puts the ship back in its wake while covering less distance than the Williamson turn, which saves time.
- Disadvantage: it is not suitable for immediate action, because the ship ends up well behind a casualty who went over moments earlier.
- Disadvantage: IAMSAR notes it cannot be carried out effectively unless the time between the fall and the start of the turn is known.
How Do the Williamson, Anderson and Scharnow Turns Compare?
The Anderson turn is fastest but needs the casualty in sight. The Williamson turn is slowest but returns the ship to its exact track. The Scharnow turn sits between them for delayed and person-missing cases.
| Feature | Williamson turn | Anderson (single) turn | Scharnow turn |
|---|---|---|---|
| Best situation | Immediate, delayed or person missing; night or poor visibility | Immediate action, casualty in sight | Delayed action or person missing |
| First rudder change | Hard over the other way at 60° | Midships at about 250° | Hard over the other way at 240° |
| Final rudder order | Midships 20° short of reciprocal | Stopping maneuver, casualty about 15° on the bow | Midships 20° short of reciprocal |
| Returns to original track | Yes, on a reciprocal course | No | Yes, into its own wake |
| Relative speed of return | Slowest | Fastest | Faster than Williamson |
| Main limitation | Takes the ship further away | Needs the casualty in sight | Not for immediate action |
Are There Other Man Overboard Maneuvers?
Yes. The racetrack turn uses two 180° turns joined by a straight leg, keeping the casualty in view throughout. It appears in US licensing exams and suits smaller, handy ships when the person is still visible.
Sailing yachts use their own methods, such as the quick-stop or figure-of-eight, because they must manage sails and avoid an accidental gybe. These rely on sail handling rather than the rudder-and-engine sequence of a merchant ship.
How Should the Ship Approach and Recover the Casualty?
Approach slowly from upwind, stop the ship to windward and let it drift down to create a lee for the casualty. Stop the propeller well before the person comes alongside.
- Wind and current: a ship drifts faster than a person in the water, so judge the stopping point to windward and allow for set.
- Propeller: stop the engine before the final approach, and keep the casualty forward of the pivot point, never near the stern.
- Rescue boat: in moderate weather, launching the rescue boat is usually the fastest recovery. It needs a trained crew and a lee to launch into.
- Heavy weather: when launching the rescue boat is unsafe, recover alongside with a recovery net, scrambling net, sling or crane.
- Casualty care: lift a hypothermic casualty as horizontally as possible, then give first aid and get radio medical advice.
Since 1 July 2014, SOLAS Chapter III Regulation 17-1 has required every ship to carry ship-specific plans and procedures for recovering persons from the water. IMO guidance on these plans is in MSC.1/Circ.1447.
How Do Crews Train for MOB Maneuvers?
Crews train through regular MOB drills, rescue boat launches and simulator courses. Bridge teams practise the turns with a floating marker, so each officer knows how the ship actually handles.
- MOB drills: scheduled under the ship’s safety management system and included in the ship’s regular drill programme.
- Rescue boat launches: SOLAS Chapter III Regulation 19 requires each rescue boat to be launched monthly where reasonable, and at least every three months.
- Simulator training: bridge simulators rehearse each turn in different sea states and visibility.
- Safety briefings and manuals: briefings, wheelhouse posters and training videos keep the rudder orders and degree values fresh.
- Equipment checks: lifebuoys, lines, lights, smoke signals and rescue boat gear are inspected regularly so they work first time.
- Debriefs: a review after every drill or real case identifies delays and areas to improve.
What Do PSC Inspectors Check for Man Overboard Readiness?
Port state control inspectors check that the ship can actually recover a person from the water. They test lifebuoys, the rescue boat and drill records, and may ask the crew to demonstrate a man overboard response.
- Lifebuoys: correct number, marked with the ship’s name and port of registry, lights and smoke signals within date.
- Bridge wing lifebuoys: at least two with self-activating smoke signals, released quickly from the bridge.
- Rescue boat: engine starts, launching appliance works, and the boat is launched at least every three months (SOLAS Chapter III, Regulation 19).
- Recovery plan: a ship-specific plan for recovering persons from the water, required by SOLAS Chapter III, Regulation 17-1.
- Drill records: man overboard and rescue boat drills logged, with the turn used and the time taken.
- Crew knowledge: the officer of the watch can explain which turn to use and the immediate actions.
Common findings in a PSC inspection are expired lifebuoy lights or smoke signals and a rescue boat engine that will not start. Missing recovery plans and crew unsure of the procedure are also frequent.
Frequently Asked Questions
What is a Williamson turn?
A Williamson turn is a man overboard maneuver that returns a ship to its original track on a reciprocal course. The rudder goes hard over, is reversed at 60° off course, and is put midships 20° short of the reciprocal.
What is the main advantage of a Williamson turn at night?
It puts the ship on a reciprocal course, nearly on the track line it ran before the fall. That makes it the best choice when the casualty cannot be seen, such as at night or in fog.
Which turn returns a ship to a person overboard fastest?
The Anderson turn, or single turn, is the fastest when the person is still in sight. The rudder stays hard over towards the casualty through about 250°, then the ship stops close to them.
What is the difference between the Williamson and Anderson turns?
The Williamson turn brings the ship back onto its own track on a reciprocal course, but takes longer. The Anderson turn is quicker but does not return to the track, so it needs the casualty in sight.
When should a Scharnow turn be used?
Use the Scharnow turn in a delayed action or person missing situation. It is not suited to immediate action, and IAMSAR notes it works effectively only when the time since the fall is known.
Why turn towards the side the person fell overboard?
Putting the rudder hard over towards the casualty’s side swings the stern and propeller away from them. This only applies in an immediate action case, when the side is known.
Does the Williamson turn take the ship back into her wake?
Yes. Steadying on the reciprocal course brings the ship back along almost the same track it was steering. The Scharnow turn also returns the ship into its wake, but the Anderson turn does not.
Is it Scharnow turn or Scharnov turn?
The IAMSAR Manual spells it Scharnow. Scharnov and Sharnov are common misspellings of the same 240° maneuver.
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