USCG Exam PracticeApplying tide corrections to charted depth
The height of a fixed bridge shown on a US nautical chart is 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
Bowditch Ch. 9 §904 states that heights of features such as bridges and lights are referenced to Mean High Water. This means vertical clearance under a bridge decreases as the tide rises toward MHW.
Cited:Bowditch Ch. 9 §904