Unit 2.a.Objective and specifications of hydrographic surveys Captain M K Barritt RN, Vice Chairman IHOCBC

“Trust in God and the Admiralty Chart” Nineteenth century hydrography and the expansion of trade

Where am I and where is my destination?

Where can I go safely?

Look for the clues on the chart

New Ships push the limits with old surveys The US Capitol Building & Grand Princess to scale.

Pushing the margins of safety

Critical evaluation of the chart is essential “It’s in colour so it must be true!”

The importance of source data The mariner must be able to judge whether the information in the chart is adequate for safe navigation for his ship. A source diagram, supplemented by guidance in a Mariners Handbook, helps him to do this.

The importance of source data

The importance of a prioritised national survey plan Defined with input from the chart user. Reflecting agreed priorities to meet SOLAS obligations. Including routine re-surveys to deal with areas of unstable seabed. Expert committee reporting back to NHC.

SURVEY STATUS

The importance of a prioritised national survey plan

Adequate surveys are a Governmental responsibility under SOLAS V Needs NHC oversight. Needs a customer committee to help define prioritised survey plan. Some or all parts of the data collection and management process can be outsourced. IHO and its RHCs can advise.