Sunday 5 June 2022

charts: updating NtM and charts: passage

How can you tell if a chart is up to date:

If you had internet access go to the UKHO and go to 'view update list by chart number'
it provides all the corrections released since the latest edition of that chart.
After you have applied the correction in the bottom left corner of the chart make a note of the number and year of the NM.

what does the NtM contain other than updates to charts?

well the admiralty notices to mariners are published weekly known as the weekly notices to mariners which comes as 6 parts:

1. explanatory notes
2. ANM, corrections to charts.
3. reprints of radio navigational warnings.
4. corrections to admiralty sailing directions.
5. corrections to admiralty list of lights and fog signals.
6. corrections to admiralty list of radio signals
'the latest critical safety information'

charts: for the coastal passage what would you highlight on the chart?

No go areas.
clearing bearings
anchorage areas.
highlight areas of danger, rocks shoals wrecks.
highlight notable depth contour lines
highlight radar conspicuous objects such as high cliffs
highlight prominent landmarks for landfall, fixing, clearing bearings and transits.
Highlight any important buoys and racons you can use, ie nav marks that can be used to assist you, obv. cant highlight all buoys but any notable ones.

highlight areas where a change in speed, call to er or master or where to call pilot, on the chart etc or where the traffic gets dense, water gets shallow etc.

light characteristics:
flashing, fixed, quick flash, isophase and occulting, alternating,
sectored?
period: the time take for the flashes and the dark period.
elevation: from the focal plane above height datum (given on chart).
and then the nominal range.

nominal range: The range of a light given a visibility f 10M
luminious range: the range of a light given the lights brightness and the current prevailing meteorological conditions.
geo range: the range of a light given the hoe, height of light and the curvature of the earth.

A tidal diamond: you can get the set and rate. the table for tidal streams is referneced normally to HW times a t a standard port.
it will give set as well as spring rate and neap rate.

spring tide: a tide just after a full or new moon and it gives the largest difference between high and low water. the highest highs and the largest lows.
neap tide: is just after a cresecnet moon or third quarter of a moon and it gives the smallest difference between high and low water.

PI's: one way you can monitor your vessel's progress by not taking a fix.
echo sounder.
clearing bearings.

How often would you fix your position?
for the coastal passage, follow the pre-planned track that is on the chart, fixing at regular intervals, depending on the scale of the chart and the proximity to navigational dangers,

'such that the vessel will remain in safe water for the distance covered by two EP's.

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