Present your plan!

[ReefGuy]

I thought I'd throw this scenerio out to you guys and see what develops.

Objective:
You're looking for a handgun that was used in a homicide.
There is the possibility that an attempt to disguise the weapon has been made.
There is no direct proof that the weapon is here, but circumstances and evidence warrant a very close look specifically at this location.

The site:
The pond is man-made and rectangular, between 200 and 300 feet wide and about 600 feet long.
It's 30'deep with sharply (approx 60 degree) sloping sides. Banks are not high, but steeply sloped at water edge.
Aquatic plants are very thick, lush and approximately 3'- 5' high. Think underwater jungle here. The plants almost completely obscure the bottom.
Visibility is about 5'. Fortunately, the bottom is semi-hard, say no more than 2"-3" of silt, then clay.
Banks are clear (no obstructions, grass) and semi-manicured. Getting gear here is no issue. Launching a small (man carriable) boat is feasable.
Site is adjacent to paved road, and area around the lake will readily support vehicles.
This is Florida. Gators are a possibility, as are snakes. Because of the relatively frequent care of the area and bottom composition, though not a major issue. No obvious nests.
Closest hospital is within 10 minutes by cruiser.
Air temperature is upper 70s/lower 80s. Water temperature is mid 60s.

Assets:
Your team consists of 6 to 10 members.
You have a metal detector, but again, this is Florida. Apart from construction debris, there may be lots of hurricane debris here. The metal detector may be a hinderance.
An underwater video system is available.
Diver/Diver and Diver/Shore comms are in use. There is only one shore unit, though.
Other assets are available, including on site compressor for tanks. Your team is not trained on Surface Supplied air.
A 3 lb weight can be thrown almost to the center of the pond. The entire area must be thoroughly be searched.
Muster on site is 0700 and will be fully light at that time. Dusk is around 1800.

Human Factors:
The crime is done. Thorough is better than speed, but approval for multiple days will not be easy at this point.
You are team leader, have two competant assistants and all members are trained, competant, healthy, rested and expecting a grueling search.
Physical fitness varies, but all members are in at least decent physical shape. Some are in excellent shape.
One is relatively new, though, and one other has missed the last two trainings (excused, it happens) and has not been in the water in 60 days.
Publix (grocery store) is catering and delivering lunch of sandwiches and drinks. We get a lot of support from these guys.
Shade is available. Equipment truck is a converted ambulance and is air conditioned and diver friendly.
News crews are likely, but road patrol has committed to send a unit for control if necessary.
Although adjacent to a road, the area is relatively secluded and not a lot of bystanders are expected.
Public support is running high. A smaller pond was drained and searched earlier in the week. Budget is not inexhaustable, though.
When we did this dive, I was in reasonable fit shape. Not a marathoner, but I was swimming daily laps both without gear and with fins/mask/snorkle.
This dive kicked my butt in the first couple of hours, during which my buddy and I searched maybe 20% of the lake. Exhaustion will be a factor.

This scenario is based (somewhat loosely) on a dive our team made a while ago. The area was in the news lately, which has gotten me thinking about that search.

So, Mr./Ms. Dive team leader, submit your plan of action.

 

[BladesRobinson]

Brother, we had a similar scenario here in Indian River County, FL several years ago. Fortunately, we had the ability to do a multi-day operation. We worked three divers (with three tenders) at the same time and had a considerable amount of construction debris in the water (nails, wire mesh, cans, bottle caps ... everything except kitchen sinks). We used metal detectors and cleared the area of debris as it was located. We ran four days overlapping the area in different directions up to the point where we located the weapon and a box of shells and casings.

In your case, I would scrap the idea of using a boat and u/w video. They just get in the way and consume resources without a good "return on the investment."

I believe getting divers under the water with metal detectors is the best option. We use a large diameter coil set on the lowest setting so we are not picking stuff up that is buried 12-18 inches below the sediment layer. I am a strong believer in removing everything from the water that causes the detector to sound. That way, if you go back to the same spot, you're not finding the same stuff two or more times. While the chief may say today that you only have one day on site, that may change. The other thing that allows me to do (as a team leader) is to see how well the divers are covering the area. If the diver finds a "D" cell battery and tosses it out of the water, I may take the opportunity to toss it back in a different area to see if it is found again. If it continues to be found, I am confident that the diver is covering the area well OR other bottom debris is distracting the diver to the point that the area can not be ruled as "searched & cleared."

It is my opinion that a thorough search of an area that is 200-300 feet x 600 feet can not be searched thoroughly in one day, especially when there is debris in the water. In the incident I worked, our search area was half the size (about 100-150' x 600') and it took three dive groups (tender & diver) working 8-9 hour days a total of four days before we had results (there was a LOT of debris).

It takes time to do a thorough search and it can't be rushed. The ultimate goal should be to start at a known point, end at a known point, and cover a known area so you can rule it out. If it's done half as good as it should, then there is alway doubt when the object isn't found.

When I get done, I alway enjoy knowing I either found the object, or it wasn't there.

One other option to give strong consideration too is inviting other teams in to help. Call it a "training day" and let teams have an opportunity to participate in a multi-agency operation. It is a good opportunity to practice in anticipation of "the BIG one." The old saying, misery loves company, will make this operation less miserable when other teams area around and there is some inter agency rivalry going on.

Just my "two cents" ... and about all it's worth.

If you need assistance, considering calling the IADRS (International Association of Dive Rescue Specialists) at 800-IADRS-911 and we'll be happy to coordinate the "training event." Right now we have more than 100 Florida PSD teams in our database and there isn't any doubt that we couldn't get something to happen in a positive (and SAFE) way there.

 

[ReefGuy]

Oops! I guess I didn't make myself clear. This is based on a dive that we have already done and have no plans to revisit. It was, in fact, an agency assist, and the actual dive had three teams working it. This was actually only one of several sites visited on this case, just this particular site turned out to be the major ballbuster. The other sites were all smaller and natural and not very deep.

The actual search was conducted over several days. Although our team participation was limited to one of those days.

I just tossed this out as an excercise to get the old brain cells working.

 

[Teamcasa]

I'm not a PSD by any stretch but why would you not just drain the pond?

 

[ReefGuy]

I'm not a PSD by any stretch but why would you not just drain the pond?

I'm not sure technically that is possible. We're talking about a huge amount of water in an area very close to sea level (around 10'). A couple of the very much smaller ponds were drained, and they refilled within a day or so.

 

[bridgediver]

Sounds like what we usually search in - without the gators.:11:

For dumped weapons the "hot zone" of the search should be within a few feet of the shore close to access/paths. Typically when someone dumps a weapon it is merely flicked into the water as they pass by and not heaved. They aren't thinking that it may be recovered by divers and are more or less more concerned with someone "seeing" them throw something - as a result its not usually a "long bomb". The weight of a handgun may have you locate it on the slope - it may not even have rolled if theres a bit of silt even at 60dg. Alot of teams don't concentrate on the shoreline enough.
My plan would be 10ft of the shoreline then search 10-50ft out from the shore along the traffic areas of the pond but would cover all shore with access.

Weed characteristics will dictate which search pattern to use but sweeps from shore won't work much past 20ft(?) in my mind from the way you describe it (although chances are the object is within that area anyway).
If you can, "vertical box" search would be the next best pattern - Swim diver out on the surface to a plotted point & drop him down; the tender slowly pulls diver in on a straight line (you have comms so even if this isn't practiced much a good speed is easy to work out with the tender/diver). Both the diver and the tender have to move over about 2.5ft for each line and take the time to grid it out with buoys and ground markings to get a good pattern. There isn't allot of stress on the diver in this pattern - swimming on the surface is where the most exertion occurs and we aren't going to swim him out that far anyway - the tender will haul him through the weeds. We've done these searches in weeds 8-10ft high but it really depends on the density, sometimes it won't work.
If that one doesn't work the overhead search from a boat is the next option. All you're doing here is decreasing the scope of the line. You might be able to do small area sweeps if the scope is decreased enough. If the plants are too bad even for that you'll need to bob the diver using him much like a probe (up and down). Obviously very time consuming, not that great for the diver (continual ascents and descents) and not that accurate unless you've got a really good tender.

I don't know if I'd bother with a metal detector in thick weeds. The diver will spend most of his effort just trying to get the device through the plants and the pattern will be messed up.

 

[BladesRobinson]

Bridge's response made me scratch my head and ask "what the heck?" ...

It's funny how one person pictures one thing and someone else pictures another. I will have to admit that I didn't read Reef's description of the bottom well enough to pick up on the "Think underwater jungle here. The plants almost completely obscure the bottom." I was reading "Aquatic plants are very thick, lush and approximately 3'- 5' high" and thinking of cat tails growing 3' - 5' high (out of the water) along the sloping shore line ... and thinking of our dive operation that was clear of bottom vegetation.

As it relates to searching along the shore, the shallow water and the sloping contour ... certainly that needs to be done and there are a host of problems searching those areas too.

With heavy bottom vegetation realized by this forum reader, my earlier strategy changes. CONSIDERABLY...

Especially if we are referring to hydrilla 3 to 5 feet high and completely obscuring the bottom; the weapon will not be located (easily).

I was told of a Nikonos camera system that was lost in hydrilla many years back at a popular dive destination in Florida, Crystal River. The spring where this camera was lost often has in excess of 100 divers doing open water check out dives every Saturday and Sunday and the camera was lost within 100 feet of the spring head. This area had thousands of divers pass over it in the course of several years. Then a hurricane came through the area years after the camera was lost and backed salt water from the Gulf of Mexico onto the spring area (killing off the hydrilla). Only then, after the hydrilla died off, was the camera was found.

In the case Reef mentions, I believe the vegetation needs to "go away" if the divers are going to search effectively. How one goes about getting rid of this vegetation is anyones guess but the folks I believe would have the best answer are the water district managers assigned to the region. I don't know of a herbicide that would work on this underwater vegetation but that's not to say the water district managers wouldn't. I don't know if the water would chill enough during the winter months to kill off the vegetation and I don't think pulling it out by mechanical means is a reasonable option either. This is a tough one.

If it's any consolation to Reef, I can empathize.

Regarding evidence likely being near the shore (an underhand toss), that is not uncommon (as Bridge mentioned) but in the operation we worked over a four day period, the woman who tossed the weapon in the water was on a fast pitch softball team and launched the weapon a pretty good distance from shore; so you have to search the entire area.

In another case I was involved in, with heavy vegetation, a drag line was brought in and worked several hundred yards along the State Road 60 canal. The vegetation and bottom muck was placed on the road and searched by hand, traffic was reduced to one lane for several days and no weapon was found. Possibly the witness was mistaken, possibly they lied ... All I can say is it wasn't where we looked.

To the credit of the incident commanders who coordinated the operation that Reef was involved in, kudos for calling in additional resources! Given the situation, I believe they all did the best they could with the options at hand.

If anyone has a good solution to this challenge, I look forward to learning what it is.

 

[ReefGuy]

Actually, with the sharply sloping sides, sweeps did end up working somewhat effectively, once away from the bank. Because of the sharp slope of the banks, the rope angle worked well once away from them. Very exhausting work, though, since we ended up pretty much pulling out the plants one at a time.

The banks were a nightmare. We handled them on the sweeps. The up and down was awful, and trying to drag the rope through the weeds made it much worse. I think if I had to do it again, I'd do jackstays on the banks, parallel to shore, with the line just above the vegitation.

Blades, dredging with a drag line might just be the way to go here. The plants do pretty much make it impossible to search effectively. Herbicide might also be a solution, but would it damage the object you're searching for?

Bridege, I don't think pulling a diver through these weeds are going to be effective. I don't know the name of the plant, but they're very tough, and would probably rip gear off the diver.

 

[bridgediver]

Bridege, I don't think pulling a diver through these weeds are going to be effective. I don't know the name of the plant, but they're very tough, and would probably rip gear off the diver.

You'd know better of course but I'd give it a try as I'm sure you guys evaluated this once there.
Actually what I'm trying to describe (badly) is that the vertical box search is much like a jackstay except the tender is controlling the line movement as well as being one end of the anchor. The difference here is that the diver would move perpendicular to shore.
Of course theres a fine line between a diver parting weeds as he progresses through and the tender pulling him through. It is done very slowly - probably 1ft/2seconds depending on the weeds and search object. This is why co-ordination between the 2 is so important.

Thanks for sharing

 

[ReefGuy]

You'd know better of course but I'd give it a try as I'm sure you guys evaluated this once there.
Actually what I'm trying to describe (badly) is that the vertical box search is much like a jackstay except the tender is controlling the line movement as well as being one end of the anchor. The difference here is that the diver would move perpendicular to shore.
Of course theres a fine line between a diver parting weeds as he progresses through and the tender pulling him through. It is done very slowly - probably 1ft/2seconds depending on the weeds and search object. This is why co-ordination between the 2 is so important.

Thanks for sharing

That does sound like an interesting approach. My concern here would be at 30', how can the diver/tender be assured they're covering the proper area? If the diver is off by 1' - 2', the weapon could be missed.