Navigation General · Passage Planning — Under-Keel Clearance
A vessel's under-keel clearance (UKC) policy in a passage plan must account for height of tide, draft, and:
- ACrew wages
- BSquat, expected swell/heave, and a safety margin✓ Correct
- CCargo value
- DEngine RPM only
Explanation
UKC must allow for charted depth and tide, the vessel's static draft, dynamic squat at speed, vertical motion from swell, and a margin for survey/density error. Many companies set a minimum percentage-of-draft or fixed-meter UKC.
Authority: IMO Res A.893(21); Bowditch
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