Open CPN Charts for Cape Verde, Gambia, French Guiana

siwhi

siwhi

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Does anyone know if these are available from any source? I have the old "free" ones (CM93?) but they are not reliable enough. I've looked in the OpenCPN chart source page and it seems nothing is available, and asked visitmhyharbour (nothing), so doubt there are options, but thought I'd ask if anyone here might know?! (Happy to pay a modest sum).
Thanks. Simon
 
siwhi said:
Does anyone know if these are available from any source? I have the old "free" ones (CM93?) but they are not reliable enough. I've looked in the OpenCPN chart source page and it seems nothing is available, and asked visitmhyharbour (nothing), so doubt there are options, but thought I'd ask if anyone here might know?! (Happy to pay a modest sum).
Thanks. Simon
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Cape Verde seemed ok, though I only visited a few islands; lower Gambia main port area ok (though if you want to go to Lamin lodge or Oyster creek the chart is essentially empty), in the upper Gambia sometimes the track snakes over ground, and there is the one underwater rock right in the middle of the river which is not charted, the water surface ripples make it visible.
French guyana ok for Iles salut, kourou, and the main Maroni channel, the latter two well buoyed to European standards though of course the other IALA; Kourou river has a berth -strictly prohibited for anyone else- for ships carrying the Ariane rocket elements, you bet they dredge and keep the entrance well buoyed.
Fantastic jungle cruising in the Maroni tributaries, though no charts at all, one has to revert to other means.

You might find updated charts for the commercial shipping areas of these places; in more remote locations I would not bother, one must be extra extra careful anyway despite what the chart says.
 
Roberto said:
You might find updated charts for the commercial shipping areas of these places; in more remote locations I would not bother, one must be extra extra careful anyway despite what the chart says.
Click to expand...

:encouragement:

Google earth images are well worth it though IMHO. The venturefurther opencpn plugin make that easy now.

Brasil charts available in the opencpn chart download plugin if you think you might end up down there.

Navionics is available online but as Roberto says, I wouldn't trust that any more than CM93. Handy as a second opinion though.
Might be some old printed options stashed away for copy in copy shops in the Canaries, but again CM93 probably as accurate as anything.

https://webapp.navionics.com

Always regret not going up the Gambia, enjoy :cool:
 
Roberto said:
...
French guyana ok for Iles salut, kourou, and the main Maroni channel, the latter two well buoyed to European standards though of course the other IALA; Kourou river has a berth -strictly prohibited for anyone else- for ships carrying the Ariane rocket elements, you bet they dredge and keep the entrance well buoyed.
Fantastic jungle cruising in the Maroni tributaries, though no charts at all, one has to revert to other means.
Click to expand...

I have made some pilotage charts for French Guiana from soundings I made in 2016, including the Criques (Coswine, Boefs Lamentin, Vaches, 1900, and Canard) off the Maroni which I'll gladly email - PM me if you like. I found that Navionics were quite accurate except in the creeks.
 
jdc said:
I have made some pilotage charts for French Guiana from soundings I made in 2016, including the Criques (Coswine, Boefs Lamentin, Vaches, 1900, and Canard) off the Maroni which I'll gladly email - PM me if you like. I found that Navionics were quite accurate except in the creeks.
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Hello,
out of interest, did you use also google earth chartlets? Did you notice discrepancies with your actual track?

I ask because I used IGN charts (official mainland geographic institute) from the internet, which are with an intentionally distorted datum but kept a correct vision of the whole structure of the criques, supplemented with google earth images: these latter -iirc they indicated 2010 sat photographs- were often significantly out, especially in the northern tributaries.
The error seemed consistent with riverbed movement, that is the "real" outside bends were to the sides of the corresponding satellite image, both N S or E W, so no datum mismatch, but an indication of what appears like a rather strong erosion and displacement of the river bed during the few years from2010 to 2017.
 
siwhi said:
Does anyone know if these are available from any source? I have the old "free" ones (CM93?) but they are not reliable enough. I've looked in the OpenCPN chart source page and it seems nothing is available, and asked visitmhyharbour (nothing), so doubt there are options, but thought I'd ask if anyone here might know?! (Happy to pay a modest sum).
Thanks. Simon
Click to expand...

Why do you dismiss the CM 93 charts ?
 
Roberto said:
Hello,
out of interest, did you use also google earth chartlets? Did you notice discrepancies with your actual track?

I ask because I used IGN charts (official mainland geographic institute) from the internet, which are with an intentionally distorted datum but kept a correct vision of the whole structure of the criques, supplemented with google earth images: these latter -iirc they indicated 2010 sat photographs- were often significantly out, especially in the northern tributaries.
The error seemed consistent with riverbed movement, that is the "real" outside bends were to the sides of the corresponding satellite image, both N S or E W, so no datum mismatch, but an indication of what appears like a rather strong erosion and displacement of the river bed during the few years from2010 to 2017.
Click to expand...

I used the gps to take the time, lat and long readings and the echo sounder for depth and made log files of the raw readings while cruising around. I then post-processed these to remove bad readings (depth = 99.9m etc) and to correct for tide. I then imported them into a mapping / GIS program. I then downloaded from IGN the GIS layers for marrées basses, translated the reference from UTM to normal Mercator using the WGS84 geoid and imported this into the mapping program. I then over-laid the two sources of data. This was accurate to better than 10m so fine for my purposes.
 
ean_p said:
Why do you dismiss the CM 93 charts ?
Click to expand...

If you're looking at French Guyana, in many places, especially around Cayenne and Degrad des Cannes, the coast has moved by more than 1km in 30 years, so I'd be wary of anything a decade old.
 
Thanks all for the suggestions. Looks like Gambia is off unfortunately because the insurance company won't cover us and we won't go without any insurance as the boat is all we have. They're still looking into French Guiana and Surinam. Hopefully, as there's a rocket launch from Kourou on 12th December and it would be cool for the kids to watch a rocket launch from a boat in the Amazon jungle. I have Navionics for that area, so at least some chart coverage. jdc - I'll ping you a PM once I've got word on the insurance. Will definitely be taking a look at Google Earth as a starter. CM93 fine as far as it goes, but as noted, it's very dated, not ideal for river mouths. Thanks again everyone. Finally decent wifi in Santa Cruz de Tenerife's fantastic new library (if ugly on the outside)!
 
siwhi said:
...Looks like Gambia is off unfortunately because the insurance company won't cover us and we won't go without any insurance as the boat is all we have. They're still looking into French Guiana and Surinam. CM93 fine as far as it goes, but as noted, it's very dated, not ideal for river mouths./QUOTE]

We had the same problem regarding west Africa and made the same decision; I've regretted it ever since.
We used CM93s in Cape Verde, French Guyana and Suriname and found them good until we went up the rivers in Surinam - I recall they showed us as being onshore in the Domburg anchorage - that said it might well've been the same with any other charts and it was merely a slight sideways displacement, don't rely on the 'little red boat', instead just use them as a chart and use mark-1 eyeballs for your river pilotage
Click to expand...
 
Contact us..we may be able to help with charts (raster) for almost any area.


BobnLesley said:
siwhi said:
...Looks like Gambia is off unfortunately because the insurance company won't cover us and we won't go without any insurance as the boat is all we have. They're still looking into French Guiana and Surinam. CM93 fine as far as it goes, but as noted, it's very dated, not ideal for river mouths./QUOTE]

We had the same problem regarding west Africa and made the same decision; I've regretted it ever since.
We used CM93s in Cape Verde, French Guyana and Suriname and found them good until we went up the rivers in Surinam - I recall they showed us as being onshore in the Domburg anchorage - that said it might well've been the same with any other charts and it was merely a slight sideways displacement, don't rely on the 'little red boat', instead just use them as a chart and use mark-1 eyeballs for your river pilotage
Click to expand...
Click to expand...
 
siwhi said:
. Hopefully, as there's a rocket launch from Kourou on 12th December and it would be cool for the kids to watch a rocket launch from a boat in the Amazon jungle.
Click to expand...

Just uploaded this totally unedited video, my 9yo holding the camera. Skip to time 0:40ish to see the fireworks.
We were in Kourou, when there are launches there is a huge forbidden area (iles du salut included), the best place to see it is upriver in Kourou.
Boat in a pitiful state, we broke the headstay on passage from Brasil.
 
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