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Franziska · 10-10-2016, 02:08

Hi,

a friend of mine is in Southamerica and needs data on currents.

In Europa I used the otcurrent plugin which was great, but I can not see where to get the relevant data for Southamerica (Mar del Plata).

Same applies for tidal data on the Southamerican Westcoast .

Anyone has a source for that?

Alternatively a free current Grib source covering that area?

Thanks so much,

Franziska

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Franziska · 10-10-2016, 05:13

No-one? Maybe someone Spanish speaking?

www.ladyrover.com

Franziska · 10-10-2016, 08:01

Anyone with connections to South America maybe?

barnakiel · 10-10-2016, 08:45

I can't help, but you can help me.

Where do you get currents grib data for other regions?

N Atlantic perhaps?

THX in advance,
b.

Franziska · 10-10-2016, 10:13

Hi Barny,

here is what I found today:

Offshore (did not try it though):
http://www.svsarana.com/oscar/

Europe:
http://www.bsh.de/aktdat/modell/stro...ngspaketee.htm

Other:
http://www.globalmarinenet.com/free-...ile-downloads/

The OTcurrents uses tidal diamond data / harmonics data which I believe seems only available in Europe and US.

Still looking for the channels in South America though...

Hope that helps.

barnakiel · 10-10-2016, 12:01

Thank you very much!

Last time I looked up gmn there was no currents data there just wind and waves. I will check everything later what I can get from oscar. I think oscar could be availble directly without going thru sarna homesite.

I am attaching a sceen dump from Maree dans le Monde. This one apparently provides tidal data (tides, in my case, but read on) for the area you want. Alas: I am using a most outdated ver 4.0. Maybe your friend can simply email the people and ask if a new version shows tidal currents? (there is tidal currents entry in the top menu there ...)

Hope this pushes things somewhat forward.

Once again, thanks for your links!

Love,
b.

barnakiel · 10-10-2016, 12:08

BTW once you know the tide, you are getting a good shot at the currents - the tidal current nearly always flows towards the crest of the tidal wave and its speed is related to the springs/neaps timing. It also flows relatively fastest (in one cycle) between the tides.

This is a rule fair enough for all general work along the coasts, etc. but not enough in fjords and wherever tide patterns are more complex (e.g. Australia Torres Strait area, etc.)

Cheers,
b.

El Pinguino · 10-10-2016, 12:14

This may point you in the right direction.. Tablas de mareas 2016 de Chile para la pesca

carlo de leo · 10-10-2016, 12:16

Hi Franciska!
Here in Brazil I dont know any information about currents...
I'll ask at our sailing club but cant promisse
Regards
Carlo

Franziska · 10-10-2016, 12:30

Thanks guys, forwarded it down South.
Btw B. I could not find a newer version of Marrée dans la monde than V4.0.

www.ladyrover.com

belle-isle · 10-10-2016, 12:45

Hi Franziska,

Just need a bit of clarification before I can provide more of an answer.
Can you say whether you are looking for data on oceanic currents or tidal streams (or both)?
And for which area? I saw you mentioned Mar del Plata, but then you talked about the channels...

Having sailed around the bottom, here's a summary of my experience.

Concerning oceanic currents, in addition to the sources already mentioned, I would add Navimail: send the following content to navimail@meteo.fr (subject line does not matter, and adjusting the area is done with the Z line):
@mto@reqt@grib@
A 1
Z -60.000 -50.000 40.000 30.000
M 0.5
D 10
P courant tprof
G 24 48 72 96 120 144 168
C bzip2
s 2.1.3
@mto@reqt@fin@

For tidal streams, data is pretty patchy and I doubt you'll find an electronic tool (although I would love to be contradicted). Tidal streams will have to be computed from tidal heights and times. Various tools such as Marées dans le Monde generally work OK, but probably best to download official tidal tables. If I remember correctly, they should be available freely on Argentinian and Chilean hydro offices websites, but I may be mistaken.

From Mar del Plata to Lemaire Strait, that is pretty essential, given the large tidal range and corresponding currents. These will be strong mostly in rivers and estuaries and are then timed in sync with the tides. Another place where looking out is necessary is around Caleta Horno. Lots of current between the mainland and the island east of the caleta. As for the Lemaire Strait, even when calculating the tides, it can be a lottery... Essential to pick "manageable weather".

Once in the channels, things get very much softer, because the tidal range drops significantly. However, if I remember correctly, there are not many tidal prediction points on the Chilean side before you reach the area of Chiloé (big tides and currents there). For most places south, tides are almost unimportant, but in places where there are narrows, it can be wise to time your passage accordingly. Especially important in both narrow channels leading to Puerto Natales area... The catch is to use the "E del P" data given on most chilean charts. This is the offset between the moon crossing the meridian and the high tide. In most cases it works fine and you'll have a decent approximation of the timing, and any official prediction likely wouldn't fare better given the complexity of the channels in the area as well as other factors coming into play, such as wind force and direction, atmospheric pressure as well as rainfall and glacier calving.

I hope this can help your friend, and I hope they actually have fun calculating all this, because it's part of the game! Plug and play nav data down there would be too easy... (they will likely also discover the offset charts, navigating in all white areas, with no hydrographic data in places, and guessing their way into glacier moraines!)

Sent from my iPad using Cruisers Sailing Forum

Franziska · 10-10-2016, 12:49

Hey, great information.
Not sure, guess it's mostly tidal currents.
I sent them a link to this thread so they can pick the right info here.

Btw. your profile name is nice, was there few days ago.
Today in Pornichet at anchor.

Many thanks!

www.ladyrover.com

belle-isle · 10-10-2016, 13:22

Quote:

Originally Posted by Franziska

Hey, great information.
Not sure, guess it's mostly tidal currents.
I sent them a link to this thread so they can pick the right info here.

Btw. your profile name is nice, was there few days ago.
Today in Pornichet at anchor.

Many thanks!

www.ladyrover.com

Thanks for the comment about Belle-Isle. My home base is La Trinité, so it's my backyard...

Coming back to Patagonia, I wrote a page about it on our blog. http://journal.belle-isle.eu/2011/06...ere-grand-sud/ . It talks about the tides among other things. If your friends don't read French, they can always Google Translate it. And if they need to, they can also PM me. Things may hav changed since we sailed down there, though, so I always welcome comments, corrections and suggestions on how to make it better and more accurate.

Cheers

Sent from my iPad using Cruisers Sailing Forum