Greetings to everyone, So, in order to manually calcualte UKC for any part of the voyage you need the ZOC of this area in order to get the correction from the table. But what do we need to do in case of CATZOC D or U? My company says that if D or U you need to manually calculate UKC. If in restricted waters then we should aquire bathymetric data. However if it is in open sea, it does not specify and such data is impossible to find. So how do I prove that the waters are safe even if we are talking about a 100m or a 200m depth? Apart from common sense, my question here also applies to inspections. Proving that you are not an elephant...
Many ENCs have simply not been assessed for CATZOC because the Hydrographic Office producing the ENC has not been able to complete the task, and ‘Unassessed’ may not necessarily mean that the ENC is of poor accuracy. ENCs may still be used in these cases, but a documented risk assessment may be necessary. The knowledge CATZOC is all the more important when vessel is passing a shallow depth area. For areas with CATZOC D & U The error is not specified or unassessed and should therefore be avoided as far as possible specially when in shallow waters. These values can greatly affect the vessel’s UKC calculation and must be considered where the depths are shallow. As a basic thumb rule the Master should plan vessel’s passage by keeping the vessel inareas shown by the triangles i.e CATZOC – A1, A2 and B and staying away from the areas covered by rectangles i.e CATZOC- C, D and U. Where the vessel can’t keep clear from passing close to the rectangles, cautions notes should be posted on the ENC using the User Maps option instructing the navigator to “Keep Echo Sounder on”and “Monitor UKC Continuously”.
GeoP17, For inspection purpose: 1) Make an RA (Risk Assessment) for navigating in an area of CATZOC U&D and file along with passage plan. 2) Caution notes posted via user maps along the affected route.
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So, in order to manually calcualte UKC for any part of the voyage you need the ZOC of this area in order to get the correction from the table. But what do we need to do in case of CATZOC D or U? My company says that if D or U you need to manually calculate UKC. If in restricted waters then we should aquire bathymetric data. However if it is in open sea, it does not specify and such data is impossible to find. So how do I prove that the waters are safe even if we are talking about a 100m or a 200m depth?
Apart from common sense, my question here also applies to inspections. Proving that you are not an elephant...
Answer from: gillnumil [translate]
Many ENCs have simply not been assessed for CATZOC because the Hydrographic Office producing the ENC has not been able to complete the task, and ‘Unassessed’ may not necessarily mean that the ENC is of poor accuracy.
ENCs may still be used in these cases, but a documented risk assessment may be necessary.
The knowledge CATZOC is all the more important when vessel is passing a shallow depth area.
For areas with CATZOC D & U The error is not specified or unassessed and should therefore be avoided as far as possible specially when in shallow waters.
These values can greatly affect the vessel’s UKC calculation and must be considered where the depths are shallow.
As a basic thumb rule the Master should plan vessel’s passage by keeping the vessel inareas shown by the triangles i.e CATZOC – A1, A2 and B and staying away from the areas covered by rectangles i.e CATZOC- C, D and U.
Where the vessel can’t keep clear from passing close to the rectangles, cautions notes should be posted on the ENC using the User Maps option instructing the navigator to “Keep Echo Sounder on”and “Monitor UKC Continuously”.
1) Make an RA (Risk Assessment) for navigating in an area of CATZOC U&D and file along with passage plan.
2) Caution notes posted via user maps along the affected route.
Comment from: gillnumil [translate]
Non-compliance: 2.1