BML Revision: Chartwork (Section 1, part 4)

Revision card 4 of 16 — Boatmaster's Licence, Tier 1 Level 2 Underpinning Knowledge, MSN 1853 Annex 10. Entirely new for Level 2, and the largest single addition in the whole syllabus jump from Annex 9 — formal chartwork isn't tested at Tier 1 Level 1.

Charts & Publications

• Know the charts and publications carried aboard: navigation and routeing charts, sailing directions, chart catalogue, notices to mariners, nautical almanac, tide tables and tidal atlases, distance tables, waterways guides and maps
• Know the procedure for correcting charts and publications, including ECDIS

Plotting & Position Fixing

• Use of navigation drawing instruments — parallel rulers, dividers
• Natural scale, distance measurement, chart co-ordinates
• Navigational terms: international nautical mile, position line, position circle
• Chart symbols and abbreviations
• Passage planning: appraisal, planning, execution and monitoring
• Identify charted objects/shore marks suitable for position fixing
• Plot position using latitude/longitude, or position lines from bearing, range, cross bearings, transits and running fixes — and know the procedures and limitations of GPS
• Explain set, drift and leeway (drift due to wind), and how to counteract them
• Calculate dead reckoning (DR) and estimated position (EP)

Radar, ARPA & Electronic Aids

• Basic operational features and controls of marine radar and ARPA
• Use of radar and ARPA to maintain safety of navigation
• Reliability, common errors and limitations of radar, ARPA, satellite positioning systems, echo sounder and electronic log
• Use of satellite positioning systems such as GPS

Quick Self-Check

• What's the difference between a DR position and an EP?
• Name two limitations of relying on GPS alone for position fixing.
• What must you check about ECDIS chart coverage before an unfamiliar passage?

Test yourself: Navigation Knowledge Checks.

Related Reading

• Meshka — grounded on a first transit after a gap in the ECDIS chart cells went uncaught through passage planning and chart ordering
• GPS and ECDIS Overreliance — when the technology becomes the blind spot, exactly the risk this section is testing you against