Hybis’ late night dip on friday night ended rather prematurely with another winch problem. They got to 2000m depth, but then spent about four hours stuck there while the engineers struggled to get the winch to do anything at all. Finally, at around 6am, Hybis came back on-board.
With that disappointment following on from Autosub’s problems the day before, it was hard to be optimistic sunday morning that things would go any better. However, shortly before 7am Autosub was launched for another attempt at 5600m. The mission was the same as saturday’s, with a slow descent punctuated by buoyancy tests, then more tests at the bottom. As the first of the buoyancy tests finished at 1000m, we all waited tensely as the depth approached the 1500m mark that had seen the end of Saturday’s dive. However, this time Autosub passed that limit and was soon on its second test at 2000m, and then all the way down to 5525m. There it started a series of tests of various pre-programmed behaviours, culminating in altitude tests with the collision avoidance system on, at progressively lower altitudes above the bottom.
The final maximum depth reached was 5598.8m. Disappointingly short of the 5600 plan, but close enough, I’m sure you’ll agree. It beats Autosub’s previous depth record, which I understand was around 4700m, and a brief look on the internet hasn’t revealed any deeper dives by AUVs that I can find, so it could possibly be a record depth for any AUV (but that is by no means confirmed, that’s just a brief google search by me). I’m sure the Principle Scientific Officer, Steve McPhail, will be contacting the people from Guinness shortly! π
Autosub came back to the surface around 4pm after nine or so hours underwater, and they got it on-board at the first attempt, this time in beautiful sunshine.
All in all, a very successful mission. Of course, there’s still a list of half a dozen things to investigate, including possibly changing out the sonar for the collision avoidance, and figuring out why one of the batteries didn’t turn on. There’s lots to do over the next 36 hours as we head south to the Casablanca Seamount, about half way between Madeira and the coast of Morocco.
I have to say that the Autosub programme is a very impressive one. The sub is very complicated, with lots of instruments and some very much cutting edge technology (for example the batteries), which adds up to lots of things that could go wrong. Despite that, the team on-board, Steve Mcphail, Miles Pebody, James Perrett, Maaten Furlong and Mark Squires, managed to track down and repair the problems that ended Saturday’s dive in less the 24 hours, all with only the tools and spare parts available on-board!
Amazing – well done! π
But, how much better would it have been with those extra 20cm of water over-head? :sarcy:
WELL DONE AUTOSUB!! π But I’m surprised the pilot has time to drink coffee at that depth π
Looks like a double expresso to me
So what was the reason the first attempt failed? (Not nice to say the problem was solved and omit an details :geek: )
At what depth would one order a large latte, a regular mocha, a double expresso and finally a double expresso?
Is there a caffeine exposure table for calculating allowable time at given partial pressures of caffeine (PPC) β If so, what is the toxic limit and corresponding depth for each drink β Is it safe to drink a double expresso at 6000 m or is it only for use as travel coffee β
Sorry Colin. It appears that the on-off switch for the whole sub failed at depth. The switch got turned off at 1500m, and then managed to turn the sub back on again on the way back up. The team discovered that the spare switch they’d brought with them didn’t work at all (most likely it had got water in it and corroded), so they’ve conjured up a new switching mechanism out of spare parts! And what’s more, it seems to work.
If you provide the approximate volumes of said drinks, I could probably calculate the depths. Apparently at NOCS they have a set of shrunken polystyrene mannequin heads that have been taken to different depths. We could use those to calibrate the pressure effects on polystyrene cups. My impression, however, is that the size is pretty constant after not much more than 1000m. More experiments will have to wait for further missions…
:geek:
I suppose the polystyrene cup (empty) is the nearest we are going to get to a cake blog from Autosub?
I’ll see what I can do. We had chocolate brownie with icecream :yum: for dessert tonight. I just don’t generally carry my camera to dinner!