Francis Meyrick

Moggy’s Tunaboat Helicopter Manual Ch.1-E “Herding, and the tow-line “

Posted on July 11, 2009

Ch.1-E Herding, and the ‘tow-line’; the Brown Ball, speedboats, netboats, green dye, seal bombs, underwater breathing devices

1) Herding, and the ‘tow-line’; speedboats and net boats.

I want to mention at this stage the concept of ‘herding’.
We will talk about it again under Section 3 (Handling your helicopter), but for now I want to touch on ‘herding’ as part of the outline of what the basic job entails.
‘Herding’ as the name implies is the use of the helicopter as a tool to scare the fish.You chase them into the set – if you’re lucky- and once they are in, you try and keep them there. While the nets slowly close…

Many ships never ask you to herd. The American ships by and large seem to regard the practice with amusement. However, the Taiwanese and the Koreans may expect you to herd, and I understand that some other Mexican and South American purse seiners will ask you as well.

The principle behind this is that fish tend to follow the leader. The leader tends to follow the baitfish, until such time as he gets really spooked, and then he just wants OUT of the set. If you can turn the leader, (or the baitfish and therefore the leader) you may turn the whole foamer around. If you play it right, maybe a hundred tons or more of fish will reverse course right back into the set.
The ‘tow-line’, as the name implies, is a heavy steel set of cables playing out off the back of the ship, which literally ‘tow’ the net. When the nets are first going down, and the ship is steaming around in a circle, there will be a huge gap at the bottom of the set (not yet closed), and a second gap behind the ship.
It is this ‘towline gap’ that I have spent many an hour guarding! Hovering at four to six feet, kicking up a huge spray, and sliding sideways up and down the length of the towline. IF… the whole foamer is heading en masse for the ‘towline’ (the still open section in the net ‘curtain’), and only the helicopter is in the right spot, and if you do succeed in turning the whole lot around, it is pretty obvious ‘whodunnit’ and who gets the glory! The reverse also applies!
Yes, there are speedboats running up and down, often more airborne than on the water, trying to do the same job. But they are no match for the helicopter in terms of agility, speed, and noise footprint. There will also be some ‘net boats’ trying to help. These are much slower, small tug boats. They are designed to hold the nets from drifting the wrong way, and therefore can grab onto the net and pull hard with a lot of torque. But they are slow to accelerate, and can hardly be called nimble.
Very often the captain will look to the helicopter as the star player to keep his fish inside the net, in that critical time period when the winches are going crazy, straining to close the net. Anywhere between twenty five and forty five minutes.

Video by Rick Faulkner

The greatest successes for the herding helicopter tend to come unexpectedly, when part of the ‘corkline’ sinks below the surface. The top of the net is marked by a continuous line of hundreds of large, bright, yellow ‘corks’. They are the size of a very large jar, or a small drum. These provide flotation so the net hangs down vertically. You will see them in all the photos on that picture the net retrieval scene.
Now the ‘corkline’ should not normally go under water. Two factors however can cause this to happen: excessive winch speed, and/or strong Ocean currents. The effect is that the top of the net, rather than resting on the surface, sinks down maybe eight to ten feet under water. This is a perfect escape opportunity for your captive foamer! I’ve seen it happen many,many times. The good news (if you’re not a tuna) is that the helicopter is very efficient at reaching the affected area in a matter of seconds. Well before the speedboats, and way, way before the netboats can come chug-chugging around.
Now you are going to make a lot of noise and try your hand at ‘sterilizing’ that critical escape window that goes down eight to ten feet. All you have to do is shush sideways up and down the submerged corkline, and you will see fish lined up on the inside, wanting to get out, but frightened to get too close to that nasty ‘thing’, making all that horrible noise. Remember sound travels really well under water.

To give you an idea: we had 150 ton in a closed set one day, with everybody very happy, until the corkline sank down! I had just departed on a search flight, and I was gone about three minutes. I got called back by a frantic captain!
For a few seconds, I couldn’t figure what was going on. All I heard over the radio was:
I looked at the observer, and he was as puzzled as I was. Then we heard:
Come back to ship! Come to shipppppp!!!….Moggy-Moggy….
feeshh get out…!!…..Aaaaahhhh!!!! “

You could tell he was just about hysterical. In those days, 1998, that was a cool hundred twenty thousand bucks about to say:
“Arrivederci, suckers! “
You would think a submerged corkline would pop right back up, but this is not always the case. I came back as fast as I could then, and then spent an interesting twenty minutes screaming backwards and forwards at low level, tailspinning, landinglight on, etc, anything I could think of. It worked… Everybody said afterwards that it was weird the way you could see part of the foamer make a dash for an area, and the helicopter cut across and block the escape. A minute later, another section would make a rush elsewhere along the line, and again be turned back.
That day, the helicopter scored big time, and in twenty minutes of efficient work, paid for three months’ worth of helicopter rent! But that is kind of rare to score so well during herding. I have also been in the exact same position, patrolling the corkline, only to have one section of fish succeed in breaking out. After that, you’re finished. History. Fish will follow fish, nose to tail, and you can hover a foot above them, making as much noise as you can, and the chances are you are wasting your time. You won’t stop a full bore nose-to-tail escape!
It’s kind of frustrating -and kind of funny!- all at the same time. They are so beautiful to watch, and you can’t help but wishing them the best as they disappear…
A whole set will empty out in minutes, and -you guessed it- the chopper gets the blame!

Some pilots love herding. Many pilots absolutely loath and detest herding. Some will refuse to do it.
Everybody who has actually done it, for real, (as opposed to the B-S’ers!) has firm views on it, one way or the other!
I have herded extensively in a Bell 47 (Lycoming O-435! Not much Power!) and also in Hughes 500 ‘C’ and ‘D’ model
helos. (Allison C20B! Oodles and oodles of power! Great!)

I guess I hold mixed views on it.
These could be roughly summed up as follows:
1. Sometimes it works spectacularly well. Most times it doesn’t seem to make much difference, although it’s maybe hard to tell.
2. For damn sure, it can be dangerous. There have been many herding accidents. Usually people stick a tail rotor in a wave.
More on this later…
3. It can be fun, on a nice day, reasonably calm sea, not too much wind. But on a windy, rough, blustery day, with a lot of spray and large waves, and the machine trying to weathercock all the time….. Yuk!
4. To be safe and efficient, it has to be done in a certain way. Otherwise it can quickly become dangerous,or a total waste of time, or even counter productive.
5. With that much salt spray, you need to wash your bird down with copious amounts of fresh water immediately afterwards.

We will talk about this again, later. For now, just be aware of the concept!

2) The ‘Brown Ball’

One day, you may have an experience similar to mine.
It was early days, and I sure didn’t know much about tuna fishing. We were circling around an area of small, patchy foamers. Suddenly,old Akaya got all excited.
“Brown Ball! Brown ball! You see?! Brown ball! “
I looked down, and, sure enough, there, floating in the water, was a sort of… brown ball.
Ten meters across, it sort of got bigger and smaller, then sharper,and then more dull. Heck if I knew what it was, or why my friend from Taiwan was so excited. So, being a naive type, who tends to fail to recognize situations when silence would camouflage ignorance, I spoke the deadly three words:
“What is it? “
In reply I got one of those looks of disgust. He went back to his binoculars, still shaking his head. Back on the ship, all I heard at the dinner table amongst lots of laughter at my expense, was ‘brown ball’.
Eventually, the captain explained.
Anchovy. Pure and simple. Lots and lots of anchovy, millions and millions of them, huddled together knowing some are going to get eaten, but hopefully it will be the next guy. Another amazing spectacle in mid Ocean, I shall be forever grateful for to have witnessed up close and first hand…
Now the significance of finding a ‘brown ball’, is that it often means the chance of a really good catch of tuna. If you can see any tuna at all on the surface, the chances are good that there’s lots and lots below. They are just feeding their faces voraciously, blind to any other consideration other than ‘Food, food, and more food’. I’ve seen ‘brown balls’ only a few meters across, maybe several nearby, and I’ve seen a whopper that filled more than half the set. They form very quickly when there is a threat, and take on the color of rich dark brown coffee. Often you will see whales there as well, or sharks.
The whales are quite majestic as they typically rise up in the middle of the ball, jaws wide, rolling over onto their sides as they swallow great gulps of anchovy. Again, spectacular, and you, you lucky thing, have a ring side seat.
The brown balls form quickly, and when the threat passes you will see them suddenly expand, the color fades abruptly, and then they sort of evaporate. All really neat stuff.
The ship of course will set around the brown ball, in the knowledge that the tuna are too busy feeding to take any notice of anything else.

So besides foamers, breezers, gatherings of birds, logs and barrels, you can add ‘brown balls’ to your shopping list when you are out on your first tuna runs.

As a postscript to this section, I might add that I was very impressed at discovering what a ‘brown ball’ was.
So I resolved in my innocent way to try and find one. Boy! Was I excited when I saw my first one.
What made it so good was the fact that El Plonker, Him-who-knew-it-all, sitting beside me, hadn’t seen it. Grrrreat!
“Brown ball! ” I announced importantly.
He lowered his binoculars, and followed my outstretched finger.
The reaction was not what I had expected…
I got that damn look of disgust again, that ‘Lord save me from baby pilots’ look.
I looked again at the brown ball. My FIRST brown ball. What I had spotted all by myself. It was definitely a brown ball. A bit creamy maybe, but definitely still brown.
“Oi! “, I said, indignantly. I should have known better.
“Brown ball! Is important, no? “
He lowered his binoculars slowly, gazed wearily at me, and moved his left hand to pat his left buttock.
Then he raised his binoculars again.
“Huh!? ”
Two words entered wearily into my headphones.
“Whale shit… “

3) green dye and seal bombs

I’ve mentioned the ‘towline’ behind the ship, and the temporary gap between the ship and the net curtain.
This is a prime area for escape for the tuna, and an area of heavy use of ‘green dye’. It gets dropped off the boats in small bags, into the water, (or thrown) and it creates a huge green, billowing underwater cloud. It’s meant to discourage the tuna from passing that way and escaping, and it probably works well.
Now the reason I mention it here,is that some bright spark always gets this real neat idea to drop green dye bags from the helicopter. I soon learned to be dead against it. Here’s why.
Firstly, they will want to deposit a huge pile of ‘ammunition’ right in the open door. It’s usually that hot, you are going to fly with the doors off. Well, that pile is going to leak all over your helicopter, and create a corrosive mess. And it’s hard to clean up. And if a bag falls out while you’re flying along, where is it going to go?
Secondly, the observers get way too excited. They will end up throwing the baggies in all directions, including up into the rotor disc and dangerously close to your tail rotor.
Thirdly, you haven’t lived until your observer, in his excitement, prior to the throw, brings his arm back, and manages to accidentally bop you right in the eye with a green dye bag! At low level! After that fiasco, (boy, was I cross), I banned them from the helicopter. There really wasn’t much need anyway, because the net boats and the skiffboat guys could cover the area just as well.

If you think that green dye bags could be interesting, well, try seal bombs in the helicopter.
I’ll tell you right now, I will NOT allow those things on board my helicopter!
I have no personal -direct- experience of them, but what follows is my understanding. If anybody can correct me,and provide more information, that would be great. I understand a seal bomb is commonly made from dynamite mixed with sand. Its purpose is to be dropped, and scare seals or fish in the right direction. The purpose of the mix, sand and dynamite, is to reduce the volatility. It succeeds in doing this, but at the expense of reliability in use. It needs to explode! It’s no use if it drops in the water and fails to go off. In order to combat that lack of reliability, there is some kind of a ‘heater’ device (I have never seen one) which is installed in the cockpit. What they then do is ‘pre-heat’ the cartridges for a few minutes, and then they drop them.
It all sounds extraordinary to me. A pilot I talked with had experienced a serious accident, where the whole tray exploded prematurely – in the cockpit! The helicopter then crashed into the water. The pilot and the observer both survived, but with serious burns. The pilot had to be rescued by the speedboat driver, who dove into the water and managed to extract the unconscious pilot…
I think I’d pass on that!

4) Underwater breathing/ escape devices

For years I have carried some kind of compact underwater breathing device. You get so used to it, you hardly notice it’s there. As a scuba diver, I’m very comfortable with their use, but somebody with no scuba training can easily find a local dive instructor to get checked out. These “Spare Air ” devices are easily available on the Internet. Mine clips to my lifejacket. There is plenty of air to roll upside down in the water, put the device in your mouth, clear it, and start breathing. Then, at your relative leisure, you can untangle yourself, unbuckle, check on your observer or passenger, and make your way out. I have done it in training many times, and I hardly used half the available air.
Now consider one fatality that occurred while I was out. An Austrian pilot crashed in a Hughes 500 off the Fairwell 707. On his first take-off from a tuna boat. He went down with the sinking helicopter, because the floats burst. Yes, they hit hard. He eventually made it up to the surface, and they got him on deck. He was lucid, and conscious, and told his mechanic (a friend of mine) that it had gotten ‘awfully dark’ down there.
He was down a fair way! On the way up however, he breathed in quite some salt water into his lungs. Some of you will already know what this can mean. It’s bad, without medical help. He survived for another twelve hours or so, but he got a very common inflammation in his lungs. This was a reaction to the salt water, and it is often referred to as ‘secondary drowning’. Essentially, you get a build up of fluid in your lungs, to where your ability to absorb oxygen is slowly reduced to the point where you literally drown –on dry land– in your own lung fluids. He was so far offshore, it would have taken the ship three or four days to get him back. Too long. What he needed was medical oxygen,urgently.
Poor Walther! We drank a few good pints of beer together on Guam, before his ill fated first voyage.
Everybody was devastated at his death. I was only a few miles up the road when it happened, and I still remember being called to the bridge of my ship and being given the sad news.

You will understand what I’m trying to say: for the small cost of these spare air bottles, about $130, the potential dividends are enormous. I strongly and wholeheartedly recommend EVERYBODY on board a tuna helicopter to wear these devices, and to be trained in their use….

Francis Meyrick

Note 1 Aeroscuttle’s input

Aug 4 at 4:34 PM
Moggy’s Tunaboat Helicopter Manual Ch.1-E “Herding, and the tow-line “

I was in over my head on herding before I even knew it.
I had read this chapter, and was certain I had a good handle on it when the opportunity came along to put my theoretical knowledge I had read from Moggy.
But I might as well been a boxer who was asked to “toe the line “, the first time I was expected to herd while the ship was “towing the line “
I got beat up pretty bad on the radio.
I was being yelled at every step of the way.
I must have been doing it all wrong.
I knew I was doing it safely, but with the language barrier, all I could make out was a few curse words.
I knew enough (from Moggy) to keep my main and tail rotors out of the water, which is a bit harder than it might sound.
I also knew enough(from Moggy) to stay clear of the cable area between the stern of the ship and the first part of the net.
This area could see the cable snap from below the surface where it’s nearly invisible to 6 feet or more above the water.
There was another dangerous area formed when the skiff boat and the ship met. Helicopters have gotten run over in that area. And to a lesser extent, you could get the same kind of cable snap there.
But whatever else I was doing was not making my Captain very happy.
All I could do was to console myself from something else Moggy said…Whatever you do probably won’t make much if any difference.
So in essence I thought of it as a kabuki theatre dance.
I just didn’t ever get to have a full dress rehearsal for my kabuki dances.


Last edited by Francis Meyrick on August 8, 2015, 9:28 am

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