Lock Operations and Navigation Procedures

Vocabulary practice flashcards covering lock operations, safety procedures, traffic signaling, regulatory compliance, and equipment maintenance.

Vessel Order of Precedence

The established priority order for passing through a lock: 1. Government vessels, 2. Passenger vessels with paying customers, 3. Commercial tows, and 4. Recreation vessels.

Reverse Hydrostatic Pressure

A condition occurring when the elevation of the tailwater is higher than the water level inside the lock chamber, prevented by keeping the valve in an open position.

Minimum Gate Pressure Differential

A minimum differential of $10\text{ feet}$ that must be placed on the upper and lower lock gates when no vessels are expected for an extended period.

Red Traffic Signal (Lock)

A signal located on the land wall indicating that a vessel must stand clear and do not enter the lock.

Amber Traffic Signal (Lock)

A signal located on the land wall instructing a vessel to approach the lock under full control, but do not enter.

Green Traffic Signal (Lock)

A signal located on the land wall indicating that the lock is ready for entrance.

Green and Amber Traffic Signal (Lock)

A signal located on the land wall instructing a vessel to enter under full control and use extreme caution.

Lock Attention or Danger Signal

Five or more short blasts of the lock whistle delivered in rapid succession to attract attention, indicate caution, or signal danger.

Head on the Lock Gate

A water level differential placed on the gate when the lock is idle to prevent pressure from the tailwater elevation pushing the gates open.

Lock Outage (Stall or Stoppage)

The duration of time during which a lock is inoperative and unable to pass traffic due to breakdowns, repairs, high river discharge, wind conditions, or normal maintenance.

Minimum Navigable Channel Draft (Nashville District)

The minimum depth requirement of $9\text{ feet}$ maintained in navigable channels by the Corps of Engineers.

Miter Sill Minimum Clearance

The required minimum distance of $3\text{ inches}$ that a vessel must clear above the miter seal before entering the lock chamber.

Marine Radio Working Channels

VHF channels used for exchanging operational information after establishing contact on channel 13: channel 12 for Wheeler Lock and channel 14 for Wilson Lock.

Navigation Accident Report Requirements

The mandatory information required after an incident: vessel name and owner name/address; names of captain/pilot/crewman involved and their time on duty; witness names; and the date and time of the incident.

Lock Master Authority

The complete authority defined in the Blue Book granted to the lock master over the movement and behavior of all vessels within the lock chamber and lock approach channels.

Prime Responsibility (Lock Master & Operator)

The foundational duty of both the lock master and lock operator to safely and efficiently transfer river traffic from one pool level to another.

Releasable Commercial Tow Data

Information permitted to be released publicly, consisting of the boat name, direction of travel, and time of arrival and departure.

Non-Releasable Commercial Tow Data

Restricted commercial traffic data consisting of barge numbers or names, commodity types, and cargo tonnage.

High Water and Flooding Monitoring Factors

The four specific project conditions that operators must track during flood events: headwater and tailwater levels, CFS, wind speed, and weather conditions/rainfall.

Rub Fender Violation Protocol

The procedure requiring an operator to record noncompliant craft into LPMS remarks, notify the lockmaster and operations manager by email, and deny lockage until resolved.

Small Craft Locking Rule

A regulation stipulating that small craft may not enter or exit a lock attached to a towboat or tow; they must unfasten and lock through independently.

Sideboard Barge Orientation

The requirement that barges carrying rock or similar material with sideboards on only one side must be oriented with sideboards to the outside of the tow to prevent cargo spillage into the chamber.

CCTV Operational Limit

The restriction stating cameras may not substitute personal observation, permitted solely for brief moments when the operator is at the control stand to operate equipment or communicate.