Section 140.635 - 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;(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 .