Topic: 360 for Search and Recovery

[instructor601]

Our Emergency Response Search and Recovery team has been fortunate enough to receive a grant to supplement our sonar equipment with additional 360 transducers. I was wondering if any of the SAR folks on here are already using them and if so has anyone had success with locating victims with them. We have been extremely successful with the sidescan technology in locating victims, but the 360 will be new territory for us. Our success is due in a large part to help from Dennis Watters of Team Watters spending several days with us searching for a victim and teaching us how to set-up the units and how to interpret the images we were seeing.

[RGecy]

Instructor 601,

I don't think they would be very useful in the initial search phase if you have a large area to cover since the boat needs to be still in order to get good quality images with 360. But I think they would be excellent once you have located a possible target and have anchored up and would like to get a better idea of where the target is in relation to the boat.

Robert

[instructor601]

A lot of our drowning's occur in local rivers where we cannot completely search the areas next to the banks for trees and other debris. We are hoping that this addition will allow us to conduct a better search of these areas and also allow us to better focus in on our target once something is located. Since the addition of the side-scans to our arsenal of tools our divers on average are in the water less than 10 minutes at tops. Once we identify a target we mark it with a buoy set-up consisting of a float, an anchor and a small tire attached immediately above the anchor; then we make a couple of more passes to insure the marker is close to the victim. The majority of the time as our divers are descending down the marker rope they come into contact with the victim before leaving the buoy set-up. We are hoping the 360 units will allow us to direct the divers from images we receive from the units while they are in the water.

[vik33]

It is known, that SI units give better images than 360 or spotlight, and they do not allow you to see what is directly under you. Those units give you more or less good images 1.2-1.5 depths aside, but at such distances even SI can hardly see any victims when the depth is more than 8-10 feet.  I think 180 degree Down Scan Imaging unit can be more helpful for such cases. It allow to see objects not only from water surface, but can be lowered down on cable to watch objects in dark water from any height that are directly under you or aside.  These two  pictures of the same object were taken 2 years ago, the first one from surface 15 ft in SI/DI mode, and the second one from 5 feet height in 180 DI mode:

[sonar2000]

In the initial search probably you would benefit from the SI (455) more than the 360. As Robert pointed out you need to be still when using the 360. With SI you are moving all the time and can cover a good bit of area. When using SI for bank/near shore searches we find that displaying only the side that is looking in the direction of interest. More screen area instead of both left and right image. Works on the principle as when viewing a recording on a standalone computer. All in all for bank searches you will probably be best with SI and your target tire/buoy system.
Chuck

[vik33]

As Robert pointed out you need to be still when using the 360.

This will not help at all. Say you stay absolutely still right above a big sunken boat with several victims on the deck, will you see them? No, you will not even see the deck itself– you will see a big dark hole instead (doubled water column) . You can see the deck ( the second screenshot) only when staying 1.5-2 depths aside, but there is no chance to see victims on the deck from such distance.
I agree SI can be more helpfull, but for seeing details right below staying still, 180 Down Scan Imaging can be much more helpfull:
http://forums.sideimagingsoft.com/index.php?topic=6742.0

[sonar2000]

Might have misunderstood you.  Yes directly below you will need to use DI or 2D. chuck

[Bradgo4goji]

A lot of our drowning's occur in local rivers where we cannot completely search the areas next to the banks for trees and other debris. We are hoping that this addition will allow us to conduct a better search of these areas and also allow us to better focus in on our target once something is located. Since the addition of the side-scans to our arsenal of tools our divers on average are in the water less than 10 minutes at tops. Once we identify a target we mark it with a buoy set-up consisting of a float, an anchor and a small tire attached immediately above the anchor; then we make a couple of more passes to insure the marker is close to the victim. The majority of the time as our divers are descending down the marker rope they come into contact with the victim before leaving the buoy set-up. We are hoping the 360 units will allow us to direct the divers from images we receive from the units while they are in the water.

We have a 360 transducer on our SAR boat with the idea of getting to spots that you can't motor over, but we are a little disappointed in the images we are getting they  not as good as SI . Now we're having problems with the 360 we need work through.

[CFDCar27]

Been using 360 scan for recovery for some time. Have advanced to higher end units now but still use HB for hasty searches till higher quality systems arrive. One of the issues you will encounter with the 360 HB is large dead spots when water is deeper must try lowering the 360 transducer you can get a much better image.

good luck

jd

[Spd 135]

How is this?  Two divers, the tree and my target in the tree.  Target is in 120' in a tree. One diver is siemount and you can see his tank and fins.  The other is backmount. The third attachment is a swimming pool with swimmers and a diver in the middle.  I extended my cable and can drop the 360 to 60'.  If the area is too small for sidescan 360 works great.

[CFDCar27]

It is great to hear others are getting into the business of 360 scan. The 360 scan is a great tooI, I would like to see HB make some minor changes to it that would really enhance the use of it in the SAR arena. Many SAR teams are using this technology because it is more affordable and many of the teams can’t afford $20,000 dollars for a once piece of equipment. I do think the 360 can be used in the initial search phase when witness  interviews are done correctly. This summer alone I have participated in three searches that would have benefited from the use of a 360 scan. We not only use 360 for searching but it is used to direct divers to the target. My divers work on a communication line and with the 360 I can walk my diver to the target and tell him just how far they are from the target and what obstacles are in front of them. It has allowed us to see under floating docks in areas where we could not operate side can. I have tried to talk to our local HB rep but I don’t think there is a lot of interest in the 360 scan for the SAR community.

[Spd 135]

When the target is in an isolated area or a known area the 360 (sector scanning) works great.  Use you team as targets.  Put them on the bottom below a buoy.  You can run side-scan and 360 a and know what the targets should look like.  If you can, get a long hose and put the air source away from the diver so that the tank is not the reflection.  The 360 can speed up the process so much.  Sometimes you get a clear image but there has to be enough space between the target and the 360.  Sometimes, like the pool image, you just get a spot.  But knowing what to look for can save time and energy.  The main thing, if deployed from a boat, is to anchor the boat on both ends so that you have a stable platform to scan from.  I attached a few pics of how mine is mounted.  When running I pull it up out of the water.