C-Map or Navionics?

[jglauds]

Hi:

I'm set to purchase the electronic charts for our Australia-Indonesia-South Africa portion of the circumnavigation. I have the Furuno NavNet3D system, and thus a choice of charts based on C-Map/Jeppesen, or Navionics. I am told that C-Map is superior by far for regions in and around the US ... and am looking for any insights from sailors who have used either/both in the intended waters -- Java, Indian Ocean, etc.

The costs are identical ...

Thanks to all

/jon

s/v ile de Grace

[jglauds]

It turns out I bought the C-Map/Jeppeson chart packs for Indonesia and beyond, and thus, for the Torres Strait region, have both Jeppesen AND Navionics for the same area ... I have not done a thorough analysis, but for the area around Thursday Island, the Jeppesen chart has ever-so-slightly more detail on navigational aids ... and in a few cases, a few more depth soundings.

Both track each other (and reality) for the coastline/shoals/bars, etc.

Of course, the underlying data is almost surely Australian, and it remains to be seen what portends in Arafura Sea and beyond ...

Just an unofficial report -- use care in using any charts, obviously.

[Jaden44]

I'm using C-Map Max-NT Wide for my passages in the Strait of Malacca and specifically island cruising off the west coast of Malaysia and Thailand. My response is specifically referenced to my experience using the C-Map Max charts covering this area. My 44’ ketch has a draft of 2mtrs.

I find that my C-Map chart package is excellent for point to point passages in waters of +20mtrs. The maximum C-Map close-in zoom range is only 0.5nm and while all very colorful, the exact location of fringe reefs and depth contours is only suggestive rather than highly accurate. In "my view" additional spot-depth and contour information is necessary to ensure safe navigation particularly if you intend to anchor in less than 15 mtrs. I’ve seen the depth sounder change from 20mts to 8mtrs in less than a boat length while the chart plotter is still indicating I’m in safe water.

Given that you have experience using C-Map charts for Australian waters, then be prepared to expect lower levels of detail and accuracy (e.g. depth contours and spot depths) of the charts produced by these same two companies for S.E. Asia. The reason is simple.

The hydrographic services of Malaysia and Thailand are responsible for the issue and update of the paper charts for their waters. C-Map and Navonics are developed using this data. Their limited hydrographic assets are generally committed to the re-survey of their respective commercial ports and their approaches. The quality and accuracy of the Malaysian chart data for their commercial ports is excellent. I expect that the survey of outer islands and cruising areas is possibly a lower priority.

The charts developed by C-Map and Navonics reflect the quality of the hydrographic date reported by these agencies. Updates and re-surveys of the no-commercial areas appear to several years out of date. One Malaysian island that is now linked to the mainland with a bridge that is not shown on electronic or paper chart. A second bridge is now under construction at Penang and cruisers report being surprised when their passage appears to be blocked by construction equipment. Two Penang marinas are not shown on the chart and the Andaman Sea Pilot reports the existence of several wash rocks in the Phuket area that are not shown on the charts together with follow-on reports that these are “hit” by yachts on a regular basis. The locations of several marinas in Malaysia are not shown and depth data for the approaches is such that entry should not be attempted without pilot assistance from the marina. This all makes for interesting sailing.

When the C-Map chart zoomed to its maximum scale of 0.5nm, the data on display does not provide the necessary high level of detail to provide for safe navigation. Any close-in approaches to unfamiliar islands and/or islands with fringe reefs must be made with extreme caution. Seasoned cruisers advise one option is to anchor off in 20-25 meters and then take a run in with your dinghy and dive on your intended anchorage to see what is actually there. Also taking into account the GPS accuracy/error factor, you could very easily find that you are closer to the reef or obstruction than your electronic chart and GPS is registering.

The Hydrographic Department of the Marine Port of the Singapore produces an excellent bound portfolio of high quality “accurate” charts (30 pages) that include some Indonesian and Malaysian Waters. Refer: “Charts for Small Craft” - “Singapore Strait and Adjacent Waterways”. I consider that this package is invaluable if you are intending to visit Singapore, transit the Strait of Singapore and/or the Strait of Malacca. See also www.mps.gov.sg

I'm reminded of the disclaimer issued by C-Map with their electronic charts which states that "only up-to-date official government charts and notices to mariners contain all the information for the safety of navigation". I respectfully suggest that when navigating in the Strait of Malacca with stopovers at Thai and Malaysian islands, their disclaimer is very relevant.

Bottom line. I do appreciate and enjoy the features of my C-Map electronic chart but recognize that the electronic data has its limitations. Electronic charts for S.E. Asia must be used cautiously and should not be your only source of navigation information.

[daddle]

I've used Navionics and C-Map in SE Asia. The C-Map has been better in all places.

[Jaden44]

Further to my earlier post [#3], I would like to clarify that the C-Map scale for "some" islands zooms in to only 0.5nm while the for others locations is 0.1nm (which provides considerably better close-in navigation details). For example, the scale for Koh Rok, Thailand zooms in to only 0.5nm for an island with a fringe reef and difficult anchorage in the S.W. monsoons.

[chala]

What I do like with C-Map is “source of data” I have not found something as good in Navionics. If you zoom out sufficiently Navionics it is possible to see the individual charts but without any information. Navionics XL9 gold 32XG Australia-wide is advertised as “cover the whole of Australia!” I have not been able to find 17A or 18. As for their mention of "seal sanctuaries" in the tropics, I have not been able to see any seals yet.

Originally Posted by chala

Some unsurveyed areas on the paper chart are shown on the electronic charts as surveyed. Due to the scale of the paper chart and if no better data is available to the electronic chart makers then the making of electronics charts is the product of learned guesswork.