….. always have a back up plan.
We are on our way back to Caldera!
Why?
We have a medical emergency onboard.
This is a drop everything and go situation – and go at top speed using all three engines.
However, dropping everything and going is easier said than done as we are towing a 6 km-long streamer and a 13 airgun seismic source that is split into five parts, and that takes some recovering.
It has to be recovered before we can go as we can’t readily manoeuvre when towing it, and we can’t do more than 5 kn through the water either.
So, in it comes and it will take several hours to recover it.
The airgun array parts are done first as they are nearer the stern and will sink quite readily as soon as they are not being towed forward any more.
Catching the float on each beam of three airguns is always a challenge as they are quite large, and surprisingly heavy in air.
They are made out of what is called syntactic foam, which is an amalgam of small glass balls all stuck together with a resin.
The entire airgun array is formed of 5 sub-arrays: four of three airguns each and a single towed from a wire.
One of the guns in this sub-array had been misbehaving and now we can see why – its hanging on only by its air hose and electrical fire cable, and has broken free of its metal chains that suspend it from the metal “I” beam.
In the lab one of our jobs has been to record the exact time and location of each shot fired and we do that with a system that we have developed based around a GPS receiver (and of course a back-up receiver) and a logging laptop (and its back-up) – all mounted in a rack to enable it to be easily bolted down to the bench.
While the shooting has been ongoing we have been preparing for the recoveries, getting our data processing and storage server up and running – it too is housed in a racking system and mounted on top of a bench for this cruise – for some cruises it goes in the rack that houses the ship’s IT system which also has the advantage of being in an air conditioned cooled constant temperature room.
No room for our equipment this time though.
And this was the plan being enacted – instead we are now currently heading back to port to drop someone off as the ship icon shows – its not on any of the profiles
Once the drop off is done, we’ll head back to the work area and start collecting the deployed instruments.
So, you always need to have a plan, and a back-up plan, and a back-up of the back-up as you never know what will happen.
And our plans are hatched and enacted on a whiteboard – and here is our plan for the shooting period – one more job to go before the first instrument is recovered.
We’ll be back in the work area on the 21st, ready to pop instruments off the seabed.
OBS'ing at sea 