How to read a paper nautical chart.
When you are going to use an unfamiliar chart there are a number of things to bare in mind. Firstly is the chart authentic and up to date? Look for:
- Admiralty chart and publication stamp on the outside and a chart number,
- Date of printing. To be checked against the cumulative list of notice to mariners (issued every 6 months)
- Other national charts are available and may be used IF they bear the stamp of the IHO and the approved national HO (Hydrographic Office) above the title. The address of the HO will be at the bottom of the chart.
- Hold the chart up to the light, it should have a watermark
- Check the bottom LHS corner. You will find the Edition Number, Edition Date and date of issue.
- Next to the above should be the year and number of correction applied. Check this is the latest correction
- Now check the sources chartlet. In the area you are navigating the source data may be old. The qualify of the source data can be found in the NP100 Mariners Handbook Caution must be taken when using old data due to the quality and frequency of the survey in use and also the quality of position fixing system at that time.
- Read the title information – this will inform your passage plan locally. Understand the datum position information to see if your position fixing system needs adjustment before applying to the chart.
- Use tidal diamond information along your intended route, taking care to use the correct standard port as shown. Confirm with reference to tidal stream atlas, which may use a different standard port schedule.
- Take careful note of any larger scale chart you may have available and use as appropriate.
- Check all symbols in the area you are navigating with special reference to chart 5011 chart symbols and abbreviations.
- Refer to sailing directions and ALL to ensure you understand the conspicuous lights and navigation marks available on the chart.
- When completing passage plans or talking to shore radio stations only the charted names of marks and places should be used.
- Consider the rising / dipping distances of day marks and night lights and determine which are conspicuous for your passage. You are now in a position to use the chart for passage planning.