SAR (Search and Rescue)

There is no time to lose, so choose a search pattern that is best suited for the situation.

In short:

Nobody is eager to get involved in a situation that necessitates a SAR-operation. Not as the object that has to be found and not as a vessel that participates in the SAR-operation. But if you do, you will have to understand that one of the keys to a successful operation is coordination and the avoidance of miscommunication. That involves understanding some specific terms and abbreviations.

When two or more SRU’s are working together on the same mission, one person on scene may be needed to coordinate the activities of all participating SRU’s.

The person in charge of the first SRU to arrive at the scene will normally assume the OSC function until the SMC arranges for that person to be relieved.

The OSC is normally a person in charge of a:

In restricted visibility, or if sufficient SRU’s are not available, it will probably be better to have the first SRU break off the expanding square search and be available for initiation of a parallel track search.

Search patterns are for the “S”-part of SAR. But let’s not forget the “R”-part (after all, that “R”-part is the one and only reason for the “S”-part). So prepare yourself to do what has to be done once the search proves succesful. That will probably be:

Be aware of drift!

Precise search pattern navigation using high-precision methods such as GPS-systems will produce good patterns relative to the ocean bottom, but not relative to the drifting search object. This could allow the search object to drift out of the search area. Therefore the currents and other forces affecting the search object’s drift during the search should be taken into careful consideration. If a smoke float or other highly visible, expendable object is available, it should be deployed at datum and the pattern should be performed relative to it.

Be aware of the risks involved!

Vessels proceeding to assist should assess the risks they may encounter on scene, including the risks such as those associated with leaking cargo, etc. Information should be sought as necessary from the distressed craft and/or from the RCC or, if no RCC is involved, the OSC.

Now you’re ready to read on….

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Note: In this section the instructions are specifically for SAR-pi, but there is a dedicated page in the manual with information about Downloading, Installing and Enabling Plugins in general. That dedicated page can be found here: Plugins-Install and Enable.

The ability to quickly deploy efficient search and rescue patterns is relevant since no matter how developed our means of transportation may get, the possibility of an emergency arising due to an accident or other reasons can never be ruled out. Specific SAR patterns have been worked out to deal with maritime emergencies. These various search and rescue patterns will be explained below.

Types of Search and Rescue Patterns

SAR-pi can generate 4 different types of search patterns. They are:

In the section “Operation” we will explain the patterns in some more detail.

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Click the SAR icon in the Toolbar

Choose the desired search pattern. In this example: Parallel Track

The plugin has a window with two sections: the top half and the bottom half.

Keywords:

Parallel Track Search:

Risk with restricted visibility

A parallel track search in restricted visibility poses problems because of the following considerations:

Click the SAR icon in the Toolbar Choose the desired search pattern. In this case: Parallel Track.

We have already seen the first parallel track search pattern in Standard actions. This was made using the default 'Starboard' button. It is for one unit and the first turn of the pattern is to starboard.

We can choose to make the first turn to port.

If two units are available we can generate the patterns for the two units as separate routes in a single GPX file.

For the first turn “Starboard” selection the following parameters were used:

“Initial leg course”

The Initial leg course is the direction you want the “legs” to point. Normally this will be at 90 degrees to the direction of the drift or, if no drift has to be taken into account, true north. In the following example we have entered 030 degrees (roughly Nort-East).

“Search Leg length”

This is the length in nautical miles of each leg.

“Track space”

This is the distance in nautical miles between two (parallel) legs.

Note: when the lookout is positioned high above the water, for instance in a crow’s nest, the lookout has a better view and can see object further away than when he would be positioned low above the water. In such cases the distance between the legs can be greater than when the lookout is low above the water. See also the explanation of “Sweep Width”.

“Number of legs”

This the number of legs you want to use in the search pattern. The higher the number, the more legs and the longer the search pattern.

“Search speed”

This is the speed of the searching ship. Note: the higher the speed, the greater the distance you can cover in a given time. But high speed might also result in a bigger risk of passing the position of the searched object without noticing that object.

We use the position of our cursor as the starting point (as described under “Standard Actions”),

Back in the top half of the window we click “Generate GPX” and save the GPX-file (as described under “Standard Actions”)

In OpenCPN we open the GPX-file as a route (as described under “Standard Actions”) and this is the result.

The pattern has 4 legs, 0.5 nm apart from each other and the first leg is orientated in the direction 030.

Activate the route and start your SAR operation!

Note: in these screenshots the “own ship” icon is pointing upwards (away from the starting-point). There is no GPS feed.

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Keywords:

Starting at the probable location of the target, the search vessels expand outward in concentric squares.

This pattern is the most effective pattern when the location of the search object is known within relatively close limits.

The commence search point is always the datum position. The first leg should be in the direction of wind and tide.

Expanding square search is often appropriate for vessels or small boats to use when searching for persons in the water or other search objects with little or no leeway.

Due to the small area involved, this procedure is less suited to be used simultaneously by multiplevessels.

Click the SAR-icon in the Toolbar Choose the desired search pattern. In this case: Expanding Square.

The parameter-window shows these fields:

The initial course should be set in the direction of the drift, or else to 000 (true North). The rest should be easy to understand, so we will not explain this further.

Following the steps described in “Standard Actions” and using the parameters in the screenshot will give a result that looks like this:

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Keywords:

The sector search is employed when the position of the lost ship or lost body is known accurately and the search has to be carried over a small area, say with each leg a length of no more than 2 to 5 NM. It is normally carried out in the area where the casualty or the object has been sighted.

The search pattern starts from the Commence Search Point (CSP). The initial course then passes through the datum.

Click the SAR-icon in the Toolbar Choose the desired search pattern. In this case: Expanding Square.

The parameter-window shows these fields:

The initial course should be set in the direction of the drift, or else to 000 (true North). The rest should be easy to understand, so we will not explain this further.

Following the steps described in “Standard Actions” and using the parameters in the screenshot will give a result that looks like this:

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Keywords:

The sector search is employed when the position of the lost ship or lost body is known accurately and the search has to be carried over a small area, say with each leg a length of no more than 2 to 5 NM. It is normally carried out in the area where the casualty or the object has been sighted.

The search pattern starts from the Commence Search Point (CSP). The initial course then passes through the datum and should be in the direction of the wind/tide or overall drift.

The search pattern starts from the datum point and continues on the initial course.

This pattern gives a very high probability of detection close to the datum point and spreads the search over the probable area quickly. With a man overboard, the ship returns immediately to the datum or, if the search target is once sighted and then lost, the ship heads for the datum.

All turns are 120 degrees to starboard. Upon completion of the search pattern, re-orient the pattern 30 degrees to the right and search a new pattern (see the dashed lines).

The advantage of this pattern is that the search vessels cross the datum a number of times. The first step is to determine the drift and carry out the operations in that direction (first leg in the direction of the drift).

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.

An aircraft and a vessel may be used together to perform independent sector searches of the same area.

NOTE: Due to the small area involved and the fact that the search vessels cross the datum a number of times, this procedure is less suited to be used simultaneously by (a lot of) multiple vessels.

Click the SAR icon in the Toolbar

Choose the desired search pattern. In this case: Sector Search

The parameter window shows these fields:

IAMSAR

USCG

The initial course should be set in the direction of the wind/tide or overall drift, or else to 000 (true North).

Example:

Note: For these examples it was decided not to use waypoint names or icons to help the clarity of the diagrams.

Following the steps described in “Standard Actions” will give a result that looks like this:

IAMSAR

Search starts at the CSP.

USCG

Search starts at the datum.

Note: the search-patterns are loaded as “routes”. And as with any route, you can adapt the appearance of that route (colour, style and width).

If you use the option for 2 passes the result will look like this:

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Note: This search pattern is not shown in the IAMSAR manual or USCG publications.

Keywords:

In the so-called “oil rig pattern”, the search sectors are placed into a quadrant.

This pattern is meant to be used when someone has fallen from a stationary object (like an oil rig is, or at least is supposed to be) and the search area is confined to one quadrant.

Click the SAR icon in the Toolbar

Choose the desired search pattern. In this case: Oil Rig (Quadrant Single)

The parameter window shows these fields:

Example:

Following the steps described in “Standard Actions” (and with these parameters) will give a result that looks like this:

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This table gives you an estimate of survival times in various water temperatures. This table is only a guideline to emphasize the need for fast action and not a means of setting an arbitrary limit on the search effort.

link::sar_survivaltimes.png[]

End of the SAR-pi manual.

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Click the SAR icon in the Toolbar

Choose the desired search pattern. In this case: Sector Search

The parameter window shows these fields:

IAMSAR

USCG

The initial course should be set in the direction of the drift/wind/tide, or else to 000 (true North).

Example:

Note: For these examples it was decided not to use waypoint names or icons to help the clarity of the diagrams.

Following the steps described in “Standard Actions” will give a result that looks like this:

IAMSAR

Search starts at the CSP.

USCG

Search starts at the datum.

Note: the search-patterns are loaded as “routes”. And as with any route, you can adapt the appearance of that route (colour, style and width).

If you use the option for 2 passes the result will look like this:

Back to top of page ↑

Note: This search pattern is not shown in the IAMSAR manual or USCG publications.

Keywords:

In the so-called “oil rig pattern”, the search sectors are placed into a quadrant.

This pattern is meant to be used when someone has fallen from a stationary object (like an oil rig is, or at least is supposed to be) and the search area is confined to one quadrant.

Click the SAR icon in the Toolbar

Choose the desired search pattern. In this case: Oil Rig (Quadrant Single)

The parameter window shows these fields:

The initial course should be in the direction of wind and tide.

Example:

Following the steps described in “Standard Actions” (and with these parameters) will give a result that looks like this:

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This table gives you an estimate of survival times in various water temperatures. This table is only a guideline to emphasize the need for fast action and not a means of setting an arbitrary limit on the search effort.

link::sar_survivaltimes.png[]

End of the SAR-pi manual.

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Click the SAR-icon in the Toolbar Choose the desired search pattern. In this case: Expanding Square.

The parameter-window shows these fields:

The initial course should be set in the direction of the drift, or else to 000 (true North). The rest should be easy to understand, so we will not explain this further.

Following the steps described in “Standard Actions” and using the parameters in the screenshot will give a result that looks like this:

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Keywords:

The sector search is employed when the position of the lost ship or lost body is known accurately and the search has to be carried over a small area, say with each leg a length of no more than 2 to 5 NM. It is normally carried out in the area where the casualty or the object has been sighted.

The search pattern starts from the Commence Search Point (CSP). The initial course then passes through the datum.

The search pattern starts from the datum point and continues on the initial course.

This pattern gives a very high probability of detection close to the datum point and spreads the search over the probable area quickly. With a man overboard, the ship returns immediately to the datum or, if the search target is once sighted and then lost, the ship heads for the datum.

All turns are 120 degrees to starboard. Upon completion of the search pattern, re-orient the pattern 30 degrees to the right and search a new pattern (see the dashed lines). This procedure can be repeated three or four times until either the victim is found or the search has been called off.

The advantage of this pattern is that the search vessels cross the datum a number of times. The first step is to determine the drift and carry out the operations in that direction (first leg in the direction of the drift).

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.

An aircraft and a vessel may be used together to perform independent sector searches of the same area.

NOTE: Due to the small area involved and the fact that the search vessels cross the datum a number of times, this procedure is less suited to be used simultaneously by (a lot of) multiple vessels.

Click the SAR icon in the Toolbar

Choose the desired search pattern. In this case: Sector Search

The parameter window shows these fields:

IAMSAR

USCG

The initial course should be set in the direction of the drift, or else to 000 (true North).

Example:

Note: For these examples it was decided not to use waypoint names or icons to help the clarity of the diagrams.

Following the steps described in “Standard Actions” will give a result that looks like this:

IAMSAR

Search starts at the CSP.

USCG

Search starts at the datum.

Note: the search-patterns are loaded as “routes”. And as with any route, you can adapt the appearance of that route (colour, style and width).

If you use the option for 2 passes the result will look like this:

Back to top of page ↑

Note: This search pattern is not shown in the IAMSAR manual or USCG publications.

Keywords:

In the so-called “oil rig pattern”, the search sectors are placed into a quadrant.

This pattern is meant to be used when someone has fallen from a stationary object (like an oil rig is, or at least is supposed to be) and the search area is confined to one quadrant.

Click the SAR icon in the Toolbar

Choose the desired search pattern. In this case: Oil Rig (Quadrant Single)

The parameter window shows these fields:

Example:

Following the steps described in “Standard Actions” (and with these parameters) will give a result that looks like this:

Back to top of page ↑

This table gives you an estimate of survival times in various water temperatures. This table is only a guideline to emphasize the need for fast action and not a means of setting an arbitrary limit on the search effort.

link::sar_survivaltimes.png[]

End of the SAR-pi manual.

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