Shallow water
Shallow water is an ascertained water depth at which the uppermost deck of a sunken vessel remain above the water's surface. The determination of the water's depth is made by the Officer in Charge, Marine Inspection (OCMI) who considers the vessel's stability (passenger heeling moment), the contour of the hull, the composition of the river bottom, and any other factors that would tend to prevent a vessel from resting an even keel.
Source
46 CFR § 175.400
Scoping language
The following terms are used in this subchapter: