46 CFR 140.635: Navigation assessment before getting underway

Last reviewed: October 14, 2026

This section requires the officer in charge of a navigational watch to conduct a navigation assessment for the intended route and operations before getting underway. The assessment must cover at least thirteen listed factors, be kept up to date, be shared with the watch, and be recorded.

What it says

  1. The officer in charge of a navigational watch must conduct a navigation assessment for the intended route and operations before getting underway.

    46 CFR 140.635(a)“The officer in charge of a navigational watch must conduct a navigation assessment for the intended route and operations prior to getting underway.”

  2. The assessment must incorporate the pilothouse resource management requirements of § 140.640, assess operational risks, and anticipate and manage workload demands.

    46 CFR 140.635(a)“The navigation assessment must incorporate the requirements of pilothouse resource management of § 140.640, assess operational risks, and anticipate and manage workload demands.”

  3. At a minimum, the assessment must consider the velocity and direction of currents in the area being transited.

    46 CFR 140.635(a)(1)“The velocity and direction of currents in the area being transited;”

  4. At a minimum, the assessment must consider the operational status of pilothouse instrumentation and controls, including alarms, communication systems, compass variation and deviation errors, and any known nonconformities or deficiencies.

    46 CFR 140.635(a)(5)“The operational status of pilothouse instrumentation and controls, to include alarms, communication systems, variation and deviation errors of the compass, and any known nonconformities or deficiencies;”

  5. The officer in charge of a navigational watch must keep the assessment up to date as conditions and circumstances change, including updates during the voyage or trip as necessary.

    46 CFR 140.635(b)“The officer in charge of a navigational watch must keep the navigation assessment up-to-date to reflect changes in conditions and circumstances.”

  6. At each change of the navigational watch, the oncoming officer in charge must review the current assessment for necessary changes.

    46 CFR 140.635(b)“At each change of the navigational watch, the oncoming officer in charge of the navigational watch must review the current navigation assessment for necessary changes.”

  7. The officer in charge of a navigational watch must ensure that the assessment and any updates are communicated to other members of the navigational watch.

    46 CFR 140.635(c)“must ensure that the navigation assessment and any updates are communicated to other members of the navigational watch.”

  8. An assessment entry must be recorded in the TVR, official log, or in accordance with the TSMS applicable to the vessel, and must include the date and time, the name of the individual making the assessment, and the starting and ending points of the voyage or trip.

    46 CFR 140.635(d)“The entry must include the date and time of the assessment, the name of the individual making the assessment, and the starting and ending points of the voyage or trip that the assessment covers.”

Common questions

When must a navigation assessment be done on a towing vessel?

The officer in charge of a navigational watch must conduct it before getting underway. It must then be kept up to date as conditions change.

“The officer in charge of a navigational watch must conduct a navigation assessment for the intended route and operations prior to getting underway.”

What must a navigation assessment entry include?

The entry must include the date and time of the assessment, the name of the individual making it, and the starting and ending points of the voyage or trip it covers.

“The entry must include the date and time of the assessment, the name of the individual making the assessment, and the starting and ending points of the voyage or trip that the assessment covers.”

What happens to the navigation assessment at watch change?

The oncoming officer in charge of the navigational watch must review the current assessment for necessary changes.

“At each change of the navigational watch, the oncoming officer in charge of the navigational watch must review the current navigation assessment for necessary changes.”

Does voyage planning under 33 CFR 164.80 also apply?

The note says certain towing vessels subject to § 140.635 are also subject to the voyage planning requirements of 33 CFR 164.80.

“Certain towing vessels subject to § 140.635 are also subject to the voyage planning requirements of 33 CFR 164.80.”

The text of 46 CFR 140.635

Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR

Navigation assessment

(a) The officer in charge of a navigational watch must conduct a navigation assessment for the intended route and operations prior to getting underway. The navigation assessment must incorporate the requirements of pilothouse resource management of § 140.640, assess operational risks, and anticipate and manage workload demands. At a minimum, this assessment must consider:

(1) The velocity and direction of currents in the area being transited;

(2) Water depth, river stage, and tidal state along the route and at mooring location;

(3) Prevailing visibility and weather conditions and changes anticipated along the intended route;

(4) Density (actual and anticipated) of marine traffic;

(5) The operational status of pilothouse instrumentation and controls, to include alarms, communication systems, variation and deviation errors of the compass, and any known nonconformities or deficiencies;

(6) Air draft relative to bridges and overhead obstructions taking tide and river stage into consideration;

(7) Horizontal clearance, to include bridge transits;

(8) Lock transits;

(9) Navigation hazards such as logs, wrecks or other obstructions in the water;

(10) Any broadcast notice to mariners, safety or security zones or special navigation areas;

(11) Configuration of the vessel and tow, including handling characteristics, field of vision from the pilothouse, and activities taking place onboard;

(12) The knowledge, qualifications, and limitations of crewmembers who are assigned as members on watch and the experience and familiarity of crewmembers with the towing vessels particulars and equipment; and

(13) Any special conditions not covered above that impact the safety of navigation.

(b) The officer in charge of a navigational watch must keep the navigation assessment up-to-date to reflect changes in conditions and circumstances. This includes updates during the voyage or trip as necessary. At each change of the navigational watch, the oncoming officer in charge of the navigational watch must review the current navigation assessment for necessary changes.

(c) The officer in charge of a navigational watch must ensure that the navigation assessment and any updates are communicated to other members of the navigational watch.

(d) A navigation assessment entry must be recorded in the TVR, official log, or in accordance with the TSMS applicable to the vessel. The entry must include the date and time of the assessment, the name of the individual making the assessment, and the starting and ending points of the voyage or trip that the assessment covers.

Note to § 140.635. Certain towing vessels subject to § 140.635 are also subject to the voyage planning requirements of 33 CFR 164.80.

Sections it refers to

The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.