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fontana · 24-10-2016, 13:20

Hi everyone,

We're a group of french scientists based in Tahiti, we need to retrieve one of our drifting instrument near Mangaia.
We'd like to rent a sail boat with a skipper to retrieve it on Rarotonga or Mangaia.

Please contact me if you're on zone with your sailing boat, we offer good conditions.

Cheers,

Clément

website : lostinthesea.eu
twitter : https://twitter.com/LostContact00

**Jim Cate** · 25-10-2016, 00:56

G'Day Clement,

We're not in a position to help, but it sounds interesting!

It would help any potential skipper to know a bit more about the task. for instance, how large is the device you wish to retrieve? And how would you locate it? And how many of your group would be joining the crew? And are those crew sailors or landlubbers?

These are practical considerations that would need to be addressed before any thoughts of commitment could occur.

Bon chance with the quest, but help us out with some greater information.

Jim

**GordMay** · 25-10-2016, 03:35

Greetings and welcome aboard the CF, Clément.

fontana · 25-10-2016, 10:59

Hi,

Thanks for your answers.

So the instrument drifts freely at a 1000m-depth. It surfaces every 5 days to transmit its position and data acquired. It stays about 30 min on surface for transmission, and then goes back to 1000m until next transmission.

The only thing you can see is the antenna, so it's impossible to find it during transmission as the only information you have is its position 5 days ago.

http://www.argo.ucsd.edu/Arvor_pourquoi_pas05b.jpg

If we are in position to retrieve it, then we can switch it to "end-of-life" mode, meaning that it will stay on surface and transmit its GPS position every 10 min.
Using a GPS device and a satellite phone, it is then quite easy to find it. We have to act fast and precisely because the surface drifting is not comfortable (biofouling, collision) and batteries may become low quickly.

Generally, this type of instrument is lost at sea when batteries are empty.
But if we could retrieve it, we could clean it, change the batteries, and then deploy it again.
Which is a more substainable way to acquire scientific data.

We have contacted the local authorities and some fishing companies, but for now, the float is too far from their coast for the operation, that's why we also look for a sailing boat which will allow us to reach the instrument even though it needs several days of sailing.

Nevertheless, it will also depend of float positions in next few days.

You can check the float position in real time on this map : http://www.oao.obs-vlfr.fr/maps/en/

http://www.oao.obs-vlfr.fr/web/image...on/map-599.jpg

cheers,

Clément

**Jim Cate** · 25-10-2016, 18:44

Again, how large is this device, and do you intend to service it in situ and re-deploy, or will you need to transport it back to some home base?

The answers to questions like these are needed in order that a prospective volunteer can asses the suitability of his boat for the job.. If you are serious about attracting a volunteer, you must address these questions.

Jim

fontana · 25-10-2016, 18:52

Sorry I forgot to answer this question.
The float is about 2 meter high, 30cm of diameter and 30kg.

I just need to bring it to somewhere I could send it back to its owner (Rarotonga seems OK), I will not perform any technical operations by myself, just put it in a box and send it.

Thanks,

Clément

**StuM** · 25-10-2016, 20:40

Quote:

Originally Posted by fontana

So the instrument drifts freely at a 1000m-depth. It surfaces every 5 days to transmit its position and data acquired. It stays about 30 min on surface for transmission, and then goes back to 1000m until next transmission.

The only thing you can see is the antenna, so it's impossible to find it during transmission as the only information you have is its position 5 days ago.

http://www.argo.ucsd.edu/Arvor_pourquoi_pas05b.jpg

If we are in position to retrieve it, then we can switch it to "end-of-life" mode, meaning that it will stay on surface and transmit its GPS position every 10 min.

So if I understand you correctly, you need to estimate a position from where the instrument was 5 days ago and then you have 30 minutes to spot an antenna breaking the surface and then reach and secure a 30kg, 2 meter long cylinder. If you don't get it, you have to wait another 5 days to try again?

Sounds like one heck of a gamble.

fontana · 25-10-2016, 21:18

Hi,

That's the normal mode (1000m, 5 days), but when I am on zone I can activate the 'end-of-life' mode : the float stays on surface and I receive its position every 10 min by SMS using a satellite phone.
Much more easier to find it !

Thanks

Clement