USCG Exam PracticeApplying tide corrections to charted depth
Bridge vertical clearances shown on US nautical charts are referenced to which datum?
- A. Mean Lower Low Water (MLLW)
- B. Mean Sea Level (MSL)
- ✓ Mean High Water (MHW)Correct
- D. Mean Low Water (MLW)
Why C is correct
The Light List Bridge Clearance Annotation states that bridge vertical clearances on US charts are shown as 'vertical clearance X ft at MHW.' Because MHW is higher than MLLW, the charted clearance represents a near-minimum condition for most tidal stages.