The positives of negative buoyancy!

Finally, some clear thinking on the importance buoyancy has in the diving community. Wait a minute, what diving community is it important to? As a matter of fact, how many diving communities are there? Why don’t you just think about those two questions while I continue with the first thought.

Buoyancy is all about Archimedes, who was a Greek mathematician/scientist living in the 3^rd century BC.

Using scientific methods he determined that “…an object immersed in a liquid partially or totally is buoyed up by a force equal to the weight of the liquid displaced”.

Well, have you thought long enough on those two diving community questions? The answer is… understanding and mastering  Buoyancy is important in every diving community.

In the recreational diving community the attainment of Neutral buoyancy at any depth is the desired objective to be considered a competent diver. However Positive buoyancy is the most sought after and taught skill for a dive profile to have a happy conclusion. Then there is Negative buoyancy which has become the bain of sport divers and those who teach them.

In the Commercial diving community the knowledge, skills and abilities  (attitudes) when it comes to buoyancy is more a job for job tool and capability. That means that Positive, neutral and negative buoyancy is mission dictated and performed professionally to a successful conclusion.

In the Special Response Diving community Negative buoyancy is king! This community includes Police divers, Public Safety divers, emergency response divers, tactical divers, military divers, forensic divers and any other group that performs underwater search and recovery missions. Believe it or not trying to find something on the bottom while neutrally buoyant is a fools errand. Now some will argue that neutral buoyancy keeps the diver from disturbing the bottom, and that may work once in a while, but if you want to find something on the bottom you must become the bottom. This is achieved only with negative buoyancy. The only way to constantly have a positive resolution to an underwater search is becoming proficient in the use of negative buoyancy.

Remember, in underwater search & recovery you get positive results when negative buoyancy is king!

Written by - Michael W. Gast

The rise of technology, and the fall of common sense.

We got the call at about 9:30 AM. We loaded up, headed out, and arrived at a small lake that was nestled in the middle of a highway interchange. We were informed by Florida Highway Patrol that the incident had happened the night before, when a person driving a pickup truck, had lost control and driven off the interstate and gone into this lake. The driver had gotten out and was fine, but the truck was now making friends with the fishes.

I geared up and walked to the waters edge as my partner got the search line. We could see the tire tracks where the vehicle had gone in, and so using that as our LSP (Last Seen Point) we started an arc search. About 10 minutes later I located the vehicle that was, in fact, a pickup truck. It was just sitting there on all four wheels glistening in the early morning sun, about 120 feet from shore.

Well, to make this story short so I can talk on what this post is really about; we recovered the truck and all was good. But when I had come up after locating the truck, the wrecker operator was just laughing and shaking his head. He told us about a recovery he was at a few days before, where 6 off duty police officers had spent 6 hours using side scan sonar, looking for a 20 foot box truck in a 50 foot wide canal that was only 20 feet deep. He just laughed and said, "It took them 6 hours with all those guys and technology, and you two come out here, and in 10 minutes, find a pickup in a 40 foot lake with a piece of string!"


Does the title make sense now? You see where I'm going with this? Dive teams get sold on all kinds of new gadgets and gear, and pay for it by trading in there knowledge of the basic principles of Public Safety Diving. A sad side note: the amount of money these teams try to get to buy said gadgets, is money that could be used for upgrading basic equipment, or be used to pay for additional training days.
Give me money to pay a team some overtime to train with the basics, and I'll give you better results then any piece of technology can produce. You think that's a bold statement? Let's take a look at a recent event in New Orleans.

I have a few things I would like to point out. First, is the amount of people who had been involved in the search. Multiple departments and volunteers assisted in looking for this missing teacher. The State Rep. in the video says that the area had been searched before but the vehicle had been missed. Now whether that was with side scan sonar or with search patterns I don't know.
Second, is the relative closeness to shore where they located the missing teachers vehicle.
Third, there were a lot of other vehicle recovered! This tells me that they do not go into these areas regularly.

As I researched this story, I kept asking one question. Why was that car missed? If divers had been in there and they were proficient at their search patterns, why was that car not located?

We have to be careful that we are not sold into the thinking that big expensive toys make it all easier, or even more effective. You can only have one of two answers. I located the object, or the object was not in the search area. Are your search methods ingrained into your team so well that you can confidently give one of those two answers? Or do you have doubt when you get done with a search?

I'm not some stone age diver that thinks that technology will take over the world. I think that there some applications where side scan sonar is very useful. Heck, I was interviewed on the Nancy Grace Show one time about the use of side scan sonar in an investigation. In that investigation it was very helpful in locating the missing person. Things like side scan sonar and metal detectors can definitely be useful tools to assist your team, but I believe that you need to know and be able to perform effectively, the basic search patterns first!

So what I'm really trying to say is: Don't sell your common sense to buy technology. That's my point. Ok, I'm done.

Search negatively my friends!

There are 2 kinds of divers in the world... -Post by Michael Gast

As a full time police diver for over twenty five years I have had the blessing and the curse of observing in-service training and its effect on the dive resource capability of various agencies. The purpose of in-service training is to hone the knowledge, skills and abilities (attitudes) of the diving resource so as to maintain a level playing field among the various diving personnel. The other side of the coin is simply training for the sake of training. This being said, what is the circumstance when your team meets for in-service training?  Since most of you reading this are in some way involved in underwater search & recovery or rescue I will leave you to decide the type of training the team in this story practiced. 

One evening my partner and I were dispatched to a possible drowning in the south end of the county. Upon arrival the fire rescue divers were just exiting the water after searching for over forty-five minutes. Their on-scene commander had determined it was no longer a rescue, but is now a recovery for the police divers.

Since the first order of business was to gather information and determine the last scene point (also referred as a datum), and never having worked this rock pit before, I asked two of the eight divers about the depth and bottom condition. They both stated that the depth was over 60 feet with zero visibility.

With the sun setting and having talked to the one witness who claims to have watched the victim go under, my partner and I swam out to the last seen point with an anchor, down line, float and a search line. Because of the reported depth the down line was over sixty feet long, although when the anchor hit bottom I still had over forty feet of line in my hands.

After securing the excess line to the float we descended to twenty feet and landed next to a Ford van sitting on its wheels. Being over two hundred feet from shore in twenty feet of water on its wheels this van was an enigma to be solved later. Being able to see the whole van in this twilight the visibility was established as fifteen feet horizontal. Using the van as our base I tended my partner as he conducted an arc search starting out ten feet and arcing 180 degrees on each pass with ten feet increments each time. On the second pass my partner signaled that he had located the victim and secured the line around the victim’s chest.

The search that we conducted lasted less than five minutes.

What did we do differently than the eight divers who searched for over forty five minutes?

When I told the last fire diver on the scene that there was a Ford van in the middle of the lake, his response was,  “ I know, we put it there for training. This is one of our training lakes”.

Well it is your turn to determine the type of in-service that goes on here!

REMEMBER!

“HOW YOU TRAIN, IS HOW YOU PERFORM WHEN IT GETS REAL ”

EBZ

Can you find my needle? It's in that haystack.

I hate that expression. It's like finding a needle in a haystack.
You might as well say "Hey! There is no way you can do this. You will fail if you try and you are a loser!"
Well I'm not a loser. Unless it's basketball. I'm about as good at basketball as a blind man is at charades.

It's said that the idiom goes back to the 1600's. Obviously they did not have proper training in search and recovery methods back then or else the saying would have never caught on.

When people lose something in a big body of water, they are surprised when I'm willing to take up the challenge. It always makes me laugh when they are surprised, because I think to myself why did they ask me if they thought it was impossible.

Several months ago I had a friend come up to me with one such challenge. He lives on a lake and was on a jet ski when he turned to sharply and fell off the jet ski. In what I'm sure was, a gloriously graceful dismount; my friends watch fell off. A very nice Invicta his family had gotten him one year for Christmas.

He was pretty bummed about losing it because of the sentimental value. 

The lake is 1 square mile and 50 feet deep. He thought it was gone and would forever haunt the fish on the bottom of that lake.
While he was telling me about all the events leading up to the heart wrenching separation, you could almost hear the doubt intensify in his voice. "No problem" I told him. "I'll come by later this week and find that thing."

When I got there I asked the same questions I always ask. I was able to narrow this haystack down to a hay bail! Once I got in the water, the bottom composition informed me that the "needle" might as well have been painted bright pink.
After an hour of searching I located the watch and recovered it to the disbelief of my friend.

Don't be so quick to see large body's of water as haystacks. Learn to ask the right questions that will minimize the area you have to search. Work from a known to an unknown. 

Search negatively my friends!