In SwedishFaulty depth data and other deficiencies in electronic sea charts
Some of Garmin’s sea charts contain errors and have been recalled by the manufacturer. The fault lies mainly in the position of the depth contours. More information from Garmin can be found at www.garmin.se/bluechart2009.
The Swedish Transport Agency calls attention to the risks of trusting only electronic aids and points out that information on sea charts (whether paper or electronic) are always based on measurement data. Such data may be old and contain errors. This may be the case with positions as well as depth data.
One recent case was that of a chemical tanker navigating with the aid of ECS (electronic sea charts) approved for replacement of paper charts. Apparently on the ECS it was not possible to see the silt bank by Fladen, and the navigator was unaware that the ship only had a few metres under the keel.
On that occasion no problems were encountered, but there are always risks involved with such small margins. Whether this was the result of a handling error or otherwise is not known, but irrespective of the cause there is good reason to underline the risks of putting too much trust in electronic aids.
SFu Safety Alert 2009-06-05,
SFu dnr 060503-2009-4055
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