Tag Archives: force 11

Seismic survey in the North Sea, 1989

Starting work at midnight, everyone piles into the instrument room at the absolute last possible minute. I’ve been on crews where you start work at 11.35 and your oppo leaves exactly at midday or midnight. On this crew, it was the other way round – you start work exactly at just before 12, and your oppos leave about 12.25 or so, earlier if possible. It doesn’t matter which you do – so long as everyone does the same thing.

We’re in a long line change. The first thing we learn is that all the starboard guns are on deck for repairs and the gun mechanics need a hand. Us two assistant observers head for the gun deck on the instant, followed later by the Observer, once the handover is complete. There are several problems. A supporting U bolt needs replacing and welding into place. One gun has a water leak in the umbilical line. Another gun needs it’s actuator replacing. This last we can do; it’s just heavy work with spanners. All three observers and all three gun mechanics work hard for a while, and eventually all the tasks are completed. The guns are launched at the last minute – only just in time as the survey line starts.

We shoot the survey line; it is mostly uneventful. An observer watches the tell-tales on various computers, of the seismic cable and the guns, and the navigator (or surveyor) steers the ship. It is 3a.m and blowing Force 5-6. There is some swell noise on our seismic recordings – that is, the sea is rough enough to start distorting the reflected noise from the guns when it appears on the seismic streamer, which is towed around 8m under the sea surface.

After the end of line, I perform a set of daily diagnostic tests on the recording instruments. This is a contractural requirement. It’s routine work but we do it for a reason, to spot problems as they crop up. After the test, it is 7.50a.m. My colleague replaces me watching the streamer, and I go for breakfast: sausages, bacon, tomatoes, chips, toast and marmalade, and tea.

We come round onto the next line, and prepare to start shooting, but the wind has risen to Force 7-8, and the swell noise in the direction of the line is unacceptable to us or the client’s representative. We have some options on this prospect – we can swing round to try a line in a different direction. The new information is programmed into the navigation computer by the trainee navigator, his boss keeping a watchful eye. Time passes: the swell noise is no better.

Then there’s a call on the intercom from the bridge, about the rising wind and worsening sea conditions. We agree; it is too rough to continue shooting. I’m despatched to the mess to tell the gun mechanics to stand by to recover all the guns. By now it is Force 8 outside and Seismariner is starting to move. The guns are recovered in stormy weather. Driving rain is hammering down, hissing on the surface of the sea. Because of the weather it takes a while, about an hour, to get all the guns aboard safely. Next, I accompany the chief mechanic and a gun mechanic up onto the quarter deck to help bring in the booms. These extend 21m either side of the vessel and are controlled hydraulically. It is pouring with rain and a sharp gale is ripping at our clothes. We’re all glad to get back inside afterwards and clean up.

I sit down shortly afterwards in the instrument room with a cup of tea. Everyone is sat around, talking. The wind is still Force 8. It’s not a BAD storm, but storm warnings are being broadcast on the teleprinter. The words “cyclonic depression” are seen. It is 10.30a.m. Suddenly, Phil, the deputy party chief, makes his decision – “get the cable in!” We stare: it’s a three-hour job in the wet and cold, and hard work. We finish work at noon…

But Phil has a hunch about the weather; that’s what they pay him for and he is right. There’s a delay about then as a trawler crosses our stern about a mile back – on top of the cable. Crash dive the cable. Fire flares into the rain and wind. By the time we start recovering the cable, it is 11.15a.m. One or two out of every five waves or so is slopping into the back deck and getting us wet; it is quite rough. Progress is slow, pushing and shoving with no hydraulic support. It seems to be getting calmer outside. It IS getting calmer; the sun appears. We wonder at our bosses decision. He appears on the back deck, telling us that Seismariner is in the eye of the storm – the “cyclonic depression” he saw on the teleprinter earlier. The sea goes down to barely 8 or 9 foot waves.

All of a sudden though, just about noon, the wind comes up again, from a different direction. Foam and spray are everywhere all of a sudden; the sea is white. Phil’s boss, the Party Chief, makes a rare visit to the back deck and endorses Phil’s decision: “Get it in QUICK” he says. The wind is now Force 10 and gusting to Force 11.