Applying tide corrections to charted depth

Bowditch Ch. 4 §403

Bowditch Ch. 4 §403 — Nautical Charts US charts show soundings in feet, fathoms, or metres referenced to Mean Lower Low Water (MLLW). The unit is stated in the chart title; always verify before plotting.

Bowditch Ch. 9 §901

Bowditch Ch. 9 §901 — Tides and Tidal Currents Tides are the periodic vertical rise and fall of the sea level due to the gravitational interaction of the moon, sun, and earth. The principal lunar tide has a period of approximately 12 hours 25 minutes.

Bowditch Ch. 9 §903

Bowditch Ch. 9 §903 — Tides and Tidal Currents Tidal currents are the horizontal flow of water associated with the rise and fall of the tide. Flood is incoming, ebb is outgoing, slack water is the brief period of zero flow at the turn.

33 CFR §164.33

§ 164.33 § 164.33 Charts and publications. (a) Each vessel must have the following: (1) Marine charts of the area to be transited, published by the National Ocean Service, U.S. Army Corps of Engineers, or a river authority that— (i) Are of a large enough scale and have enough detail to make safe navigation of the area possible; and (ii) Are currently corrected. (2) For the area to be transited, a currently corrected copy of, or applicable currently corrected extract from, each of the following publications: (i) U.S. Coast Pilot. (ii) Coast Guard Light List. (3) For the area to be transited, the current edition of, or applicable current extract from: (i) Tide tables published by private entities using data provided by the National Ocean Service. (ii) Tidal current tables published…

46 CFR §176.645

§ 176.645 § 176.645 AHE Procedure. (a) To complete the underwater survey you must— (1) Perform a general examination of the underwater hull plating and a detailed examination of all hull welds, propellers, tailshafts, rudders, and other hull appurtenances; (2) Examine all sea chests; (3) Remove and inspect all sea valves in the presence of a marine inspector once every five years; (4) Remove all passengers from the vessel when the sea valves are being examined, if required by the Officer in Charge, Marine Inspection (OCMI); (5) Allow access to all internal areas of the hull for examination, except internal tanks that carry fuel (unless damage or deterioration is discovered or suspect), sewage, or potable water. Internal sewage and potable water tanks may be examined visually or by no…

46 CFR §28.225

§ 28.225 § 28.225 Navigational information. (a) Each vessel must have at least the following navigational information on board: (1) Marine charts of the area to be transited, published by the National Ocean Service, the National Geospatial-Intelligence Agency, U.S. Army Corps of Engineers, or a river authority that— (i) Are of a large enough scale and have enough detail to make safe navigation of the area possible; and (ii) Are currently corrected. (2) For the area to be transited, a currently corrected copy of, or applicable currently corrected extract from, each of the following publications: (i) U.S. Coast Pilot; and (ii) Coast Guard Light List. (3) For the area to be transited, the current edition of, or applicable current extract from, each of the following publications: (i) …