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  • : Histoires d'un scaphandrier or the Stories of a Commercial Diver
  • Histoires d'un scaphandrier or the Stories of a Commercial Diver
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30 juillet 2015 4 30 /07 /juillet /2015 19:08
A little story of a saturation dive

Year of our Lord 1981.

It is now a few days that I’m aboard the DSV Tarasco who is currently working in the Gulf of the Mexico.

Marseille operations service has sent me here because apart my offshore work that I started again a few months ago, I also have a lot of experience in civil engineering which means thousands of diving hours without visibility and as I’ve heard that’s what the company is looking for because HERE in the GOM they say that the "vis" is very bad.

For several months now, the diving operations merely consists to realize hyperbaric welding pipeline connections and therefore during this first week on board I pass a lot of hours in the welding chamber to study all the type of gear and equipment I’m going to use underwater.

We are now a few days later and the Superintendent informs me that I am part of the team that has to enter in saturation at night.

Indeed, a new connection of two 36” pipelines that had recently been laid on the bottom by a lay barge has to be done.

The 'Sat' entry is expected around 22:00 and for the start of this new operation, only 9 divers will be compressed.

A little story of a saturation dive

The diving system of our DSV consists of three 2000 diam. deck compression chambers connected to a wet pot. Each chamber has four bunks but for comfort reasons the divers will be divided into them by teams of 3.

As we still have a few hours to go before the pressurization, each of us bustles to prepare his bunk with fresh sheets and bring the personal effects that will be needed during the stay.

Live at 3 people inside 2 meters diameter chamber is not very comfortable even more if we remove the 30 cm from the floor, it really leaves very little room, especially for the one who has to sleep on the top bunk. Generally it is the thinnest diver of the team that is sacrificed and designated to sleep at the top, although that some teams choose to make a rotation.

22 hours approach, after a final briefing with the superintendent we all go to the LST control room where some will take the opportunity to smoke a last cigarette. It’s time to enter our respective chambers. At the entrance the chamber operators make a last control to check our pockets to ensure that nobody carry illegal or hazardous products such as: cigarettes, matches, lighter, or alcohol. Sex magazines are of course allowed.

There it is, one of the life support technician starts the regeneration system and after having closed the door begins to compress the chambers with air up to the depth of 10 meters. This first part of the compression is designed to raise the partial pressure of oxygen to 420 mb. Then the diving system is pressurized with pure helium to the storage depth which for us today will be at 30 meters.

During the compression, the soda lime filter fan is switched on to help the mixing of ambient gases, but as this is not enough, we are asked to stir the atmosphere with our towels. As the storage depth is not deep, the compression speed can be done at about 1 m / min. which allow us to be at depth within 30 minutes.

It is now 23:00, and the supervisor is already calling us for a first dive.

The No. 1 chamber to which I belong has randomly been selected to do this dive and I am designated to be the diver one. My mate Laurent will be diver two and Samo will be our bellman.

The diver’s one role is to lead the dive. He is the one who speaks with the supervisor on the manner to do this or that and how it can be done.

The diver two is there to attend the diver one and he generally takes no decision on how to the conduct the operations. He also return to the diving bell in the middle of the dive and is then replaced by the bellman.

The bellman is the diver who stays in the bell to assist and monitor the divers. While Samo passes inside the bell to make the pre dive checklist Laurent and I go to wet pot to dress ourselves with our hot water suits and safety harness. Meanwhile, the supervisor reminds us via the intercom the purpose of our mission for this night dive:

- Search and localize the first 36 "pipeline.

- Mark it up.

- Align the pipeline along its final position.

The checklist is now completed and the bellman informs us that we can pass into the bell. Once inside, we settle on the tiny seats so that Samo can close the lateral door of the bell.

- Bellman: Surface door closed.

- Surf: Ok bellman I call someone from the chamber to come and close the other side.

Once the second door closed, the trunking located between the wet pot and the bell is depressurized and the bell is disconnected from the living chambers.

The surface team at their turn closes the outside lateral door and brings the bell over the moon pool where they still connect the guide cables.

The descent can begin.

During the descent, Samo monitors the pressure gauge of the side door to verify if the tightness is good. He also announced the depth every ten meters until the bottom door is slightly pushed open by the hydrostatic pressure and lets a little flush of water in.

- Bellman: Surface door open stop the bell

The diving bell is stopped and our bellman fully opens the bottom door, then by using the pressurization valve he lowers the water and at the same time asks to resume the descend until the bell comes at 4 to 5 m from the bottom. The different gas and hot water supply circuits are opened and Samo can now assist me to equip myself.

First connecting the hot water hose... Ah! I appreciate the arrival of this hot water at 35 ° c. It must be said that I began to really get chilly in this atmosphere of heliox.

- Me: OK Samo, you can put my KMB 17 on.

Once done I quickly test my gas supplies with the freeflow and the auxiliary non-return valves.

On the surface, the supervisor has connected me on a 12/88 heliox mixture so I dive with a PPO² between 400 and 800 mb.

- Me: HEUH! SAMO do not forget to put the locking pin in the neck clamp because I don’t want to lose my helmet as it arrived to some poor divers.

OK, that's good.

- Me: Surface, how do you read me?

- Surface: 5 on 5 diver one (D1).

- D 1: Ok, I'm ready to go; can you tell me on what side I am supposed to find the pipe?

- Surface: in principle at about 09:00 O’clock.

- D 1: Ok I’ll go out.

I slowly let myself go through the small bottom trunking and I find myself in the water.

- D 1: AAH! AAH! surfaaace ! What is this bullshit?

- Surf: Oh! What happens why do you scream like that?

- D 1: AAH! AAH! My eyes! I'm too much dazzled, they told me that here there was no visibility and I have at least 30 m to the level of the bell AAH!

- Surf: Francis stop making the fool and go to work.

- D 1: OK chief.

I let myself fall on the bottom and I start to move slowly towards the 9: 00 O’clock direction. While I walk on the bottom, I realize that the visibility decreases rapidly because of my movements on this muddy soil but nothing catastrophic as I still can see at 3 meters.

Ah! These French divers, it would do them good to come to our small Belgium and follow a diving course in our dark waters.

- D 1: Surface, can you ask the bellman if I still go in the right direction?

- Surf: Bellman… is the diver going to the right direction?

- Bellman: affirmative.

- Surf: OK for the direction Diver.

- D 1: Ok I continue.

A few moments later:

- Bellman: Surface... can you tell the diver that he is at the end of his umbilical.

- Surf: Diver you are at the end of your umbilical.

- D 1: Ok... I’ve found nothing... Say to the bellman to hold my umbilical tight because I'll start a circular.

- Surf: OK Diver.

- Bellman: Ok surface I keep it tight.

As I don’t think to be Cuckold as some other divers are, I suspected well that I would not find the pipe immediately. Slowly I begin to turn around the bell well taking care at my 50 m umbilical. Then after a certain time (time that takes the barrel of the gun to cool down) I see a dark mass appear in my field of vision. Here it is.

- D 1: Surface... that's it, I found the pipe.

- Surf: Bellman... can you tell me the direction of the diver’s umbilical?

- Bellman: 3:00 O’clock.

- Surf: Diver the pipe is at 3:00 O’clock.

- D 1: That’s what I suspected, you surely read your plan upside down.

- Surf: §; %,? O(( .. Diver can you give me the silting up of the pipe?

- D 1: Yes... silted up to half.

On the surface, the supervisor informs the project manager of the situation. He decides to move the boat.

- Surf: Diver... we are going to move the boat some 20 m towards the pipe.

- D1: Ok, tell the bellman to slowly recover my umbilical during the displacement.

- Surf: Bellman... we are going to move the boat towards 3: 00 O clock, you pick up the umbilical when needed.

- Bellman: understand will pick it up.

On the surface, the Chief informs the bridge that they can move the boat for 20 meters to starboard. As it is a dynamically positioned vessel, the officer in charge enters the data into the computer, and starts the maneuver.

On the bottom of the ocean, I hear that the thrusters are beginning to turn more regularly while that at the same time I can feel that Samo resumes my umbilical. After a few minutes the surface calls me:

- Surf: Ok Diver we have done 20 m.

- D 1: Ok well received.

- Surf: Francis, we are going to send you the basket with the pinger in it.

- D 1: Ok, did you install a strobe light on the basket?

- Surf: affirmative and there are also a few fluo light sticks on it.

- Surf: Ok diver, the basket comes down.

- D1: Coming down.

I put myself on the pipe and look towards the surface. After a few moments, I begin to see the flashes of the strobe in the middle of a green halo light, that's it here is the basket.

- D 1: Surface, I see the basket... ok continue to descend slowly. OK stop! Basket on the bottom.

- Surf: Stop! Basket on the bottom.

I go to the basket and take the pinger.

- D 1: Ok surface you can pick up the basket.

- Surf: Received.

- Surf: Francis, can you now move along the pipe with the pinger so that we can plot its exact position.

- D 1: Ok surface, I begin to walk along the pipe.

A little story of a saturation dive

While I move, the pinger sends an acoustical signal every second which is picked up on the surface and plotted on a chart.

I move along the pipe for about 300 m and from time to time ask to displace the boat so that I’ve not to work at the end of my umbilical.

While I’m walking on the bottom, my two colleagues gently discuss in the bell. But due to their breathe, their metabolisms will consume approximately 30 liters of oxygen per hour and produce about the same amount of CO². For the CO², no problem the bell is equipped with a scrubber that contains soda lime, a CO² absorbent but for the oxygen all the parameters are monitored by the surface and now the supervisor has noticed that the PPO² in the bell decreases, where his reaction:

- Surf: Bellman you make two additions of oxygen.

- Bellman: Ok two additions.

At the bridge, the superintendent realizes that the trace of my survey does not match with the final position the pipeline should have. It is located approximately 45 m out of his theoretical axis, result it will be necessary to slide the pipe.

- Surf: diver.

- D 1: Yes I listen

- Surf: Ok, we have to slide the pipe some 40 m to port over a distance of 300 m.

- To make the pipe lighter we are going to send you 10 T parachutes that you will fix every 30 m starting from the beginning.

- D 1: Ok well received, but as the pipe is half buried, I’ll need the Galleazzi and a needle to pull the slings under the pipe.

- Surf: Ok well received, we send you the water lance with the basket together with a first parachute.

- D 1: Ok understood, can you ask to diver two to prepare.

- Surf: Laurent, you can prepare yourself to help Francis to install the 10 T parachutes.

- D 2: Ok, I dress up.

In the meantime the basket is back at the bottom, I put the pinger back in it and recover the galleazzi water lance and the needle and I go to the place where I have to dig my first hole. There at some 5 meters from the pulling head I start to make a hole in the mud in order to facilitate the passage of my needle (rebar shaped at the diameter of the pipe) under the pipeline.

Once the lifting sling is in place and tight around the pipe I leave the place and move some 30 meters further to start the digging of the next hole and let Laurent fix the parachute and fill it by using the inflation line coming from the surface.

A little story of a saturation dive

During the four next hours, Laurent and I install the series of parachutes on the pipeline.

- D1: Ok surface all parachutes are in place and filled up.

- Surf: Ok divers we will now return at the beginning of the pipe with the boat and once in position we will let down the lifting cables from the three davits.

- D 1: Ok well understood.

While the DSV moves back to the pulling head we are on stand-by on the counterweight of the bell. I take advantage of that movement to go for a quick drink.

20 minutes later, the boat is in position.

- Surf: Ok divers boat is in place, we will start to descend the davit number one cable.

- D 1: Ok you come down on number one.

The three spaced cables are attached to the pipe in the same manner as the parachutes slings. An hour later:

- D 1: Ok surface all the davit cables are installed.

- Surf: Ok Divers we are going to slowly heave the pipe to the surface. In the meantime Laurent you will change with Samo and you Francis put yourself at shelter under the bell.

- D2: Ok I return to the bell pick up diver’s slack.

- D1: Ok I go under the bell.

- Surf: Bellman, Laurent comes back to the bell to change with you.

- Bellman: Roger.

A little story of a saturation dive

The pipe is now slowly brought to the surface with the 3 davits. This lift allows the pipeline to have a correct bending up to the touch down point, thus preventing it from breaking.

- Surf: Ok divers, the pipe is at the surface, we will start the shifting.

- D 1: Well received, we stay away.

The boat now moves laterally with 5 meters steps and this until the pipe is in the planned axis. It is now Samo who has joint me on the counterweight until the end of the displacement maneuver.

- Surf: Divers Ok, the pipe is in the axis, we start to bring it down.

- D 1: Ok surface coming down.

A few minutes later the pipe appears over our heads.

- D 1: Surface, I see the pipe it is at about 10 meters from the bottom you can continue to come down.

- Surf: Ok diver one I warn you as soon as we have no more tension on the cables.

- D 1: Ok.

Slowly the pipe sets down on the bottom but because of the surface sea state the pitching and the rolling of the boat is transmitted on the tube which rolls a bit around. Result: a cloud of silt is lifted and rapidly the visibility is reduced to nil.

- Surf: Ok divers, the pipe is laid back and there is slack in the cables. Francis you disconnect the davits and you Samo you start to deflate and recover the parachutes.

- D 1: Ok I do the davits.

- D 2: Ok I deflate the 10Ts.

Here we go again and this work will take us 2 more hours. Then finally I can announce:

- D 1: Ok surface the pipe is clear.

- Surf: Perfect guys you may return to the bell, dive completed.

As it is a little over 9 hours that I am in water, Samo proposes me to enter first. Thing that I accept gladly, "thank you Samo". But just before entering he taps me on the shoulder and makes me sign to watch in a given direction.

OOOUAHHH! Look at that. A bunch of small sharks are turning around the diving bell, there are at least a dozen of them.

- D1: Surface... we’re surrounded by small sharks... it is super nice to see.

- Surf: what! And you have not seen them on the bottom?

- D1: Well no, visibility was bad since the displacement of the pipe.

- Surf: Are they great?

- D1: No, they don’t go over a one fifty meter.

- Surf: It’s ok now we have no time to lose looking at little fishes. Enter the bell before that they eat up your ass.

I get through the hatch and to facilitate my entry Laurent opens the lower valve of the Swan neck which allows the water to rise some 0.4 m more in the bell.

As soon as I have my KMB 17 out of the water, I struggle due to fatigue to keep my head straight. I look a bit like David Niven in the brain and Laurent is obliged to straighten my head to be able to remove the helmet.

Whew! It’s done, I feel better.

A little story of a saturation dive

Once all my gear removed I give a hand to the bellman to tidy up the material before letting the diver two in.

OK, Samo at his turn is in the bell.

- Bellman: OOUAHH! SAMO LOOK: what happened to your fin?

- SAMO: Oh shit what is that?

In fact, the buckle of his left fin has disappeared to the level of the foot and from what’s left on it we can clearly see that it was ripped off by a beast that had some good teeth like a shark or big moray eel.

- Me: And you have felt nothing?

- SAMO: Well yes I felt something, but I thought that I had hanged something.

- Me: Well my friend for the same price you could have lost a few toes. So you see that what they told us on the surface «If you do not see the shark, he can't see you either» is just bullshit.

A few minutes later everything is tidy and all the unnecessary valves are close. The bellman chases the excess of water via the pressurization valve. He then inspects the gasket of the bottom door and finally closes it. Still a little blow of pressure to ensure the good sealing of the door and we are ready to go.

- Bellman: Ok surface door sealed you may pick up the bell.

- Surf: Ok coming up.

While the bell rises to the surface, we discuss everything and anything and of course about the fin. The bell is now at the surface, and we have to wait a few minutes more to be reconnected to the system.

Finally we hear the equalizing noise in the trunking and:

- Bellman: Ok surface, door open.

- Surf: Ok guys have a good night and thank you.

- Divers: Ok chief we hear you tomorrow.

Each in turn we slide through the small tube that brings us in the wet pot.

There the next bellman is already waiting to enter the bell to make the checklist.

At the microphone, Serge the chamber operator is giving us the menu.

- "Ok guys, today you have the choice between poo on crap or shit on poo."

I will take the first dish, anyway crap or not, food has anyway not much taste in saturation. But still a few days to go and maybe we will be entitled to something better because the catering just got fired.

While Samo and Laurent are discussing with the two following divers, I take the opportunity to take a nice hot shower, because I find that it's a little chilly in our chamber. It is true that 30 ° c in a heliox atmosphere is a bit low.

It now remains to take our meal and then jump in our bunks for a long sleep since we will be quiet for the next 15 hours.

Papy One

Photos and diving Art taken from internet.

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