A route crosses an unfamiliar symbol in apparently deep-coloured water. What should you do before relying on the route?

Symbols and abbreviations carry defined meanings and may be qualified by notes, depth, danger or chart context. Colour helps organise the display but does not override the exact symbol. Resolve the governing chart evidence first, then apply tide, draught, margin and route choice. Revise this in Read Depths, Symbols, and Notes.