Bridge Terminology

The bridge is the place where the ship is controlled when it is underway. It is manned continuously when underway but only manned in port when making preparations for getting underway. The commanding officer (CO) is ultimately responsible for the ship but is not always physically present on the bridge. When the CO is not on the bridge, the Officer of the Deck (OOD) controls the ship. When the CO is on the bridge, he or she may or may not assume control of the ship from the OOD.

A secondary conn is located within the ship near the bow that serves as a replacement for the bridge if the bridge has been damaged so much that the ship can no longer be controlled from it. The secondary con is usually only manned during wartime general quarters conditions. It is controlled by the executive officer (XO) in case the CO has been incapacitated or killed.

Watch Personnel

• Officer of the Deck (OOD). Responsible for the ship and to the Commanding officer. Duties include:
  • Keep continually informed concerning the tactical situation and geographic factors that may affect safe navigation of the ship, and take appropriate action to avoid the danger of grounding or collision according to tactical doctrine, the Rules of the Road, and the orders of the commanding officer or other proper authority.
  • Keep informed concerning current operation plans and orders, intentions of the officer in tactical command and the commanding officer, and such other matters as may pertain to ship or force operations.
  • Issue necessary orders to the helm and main engine control to avoid danger, to take or keep an assigned station, or to change the course and speed of the ship according to orders of proper authority.
  • Make all required reports to the commanding officer. When a command duty officer is specified for the watch, they make the same reports to the command duty officer.
  • Ensure that required reports to the OOD concerning tests and inspections and the routine reports of patrols, watches, and lifeboat crews are promptly originated and that the bridge watch and lookouts are properly posted and alert.
  • Supervise and direct the personnel on watch on the bridge, ensure that all required entries are properly made in the Ship’s Deck Log, and sign the log at the conclusion of the watch.
  • Issue orders for rendering honors to passing ships as required by regulations and custom.
  • Ensure that the executive officer, command duty officer (when assigned), and department heads concerned are kept informed of changes in the tactical situation, operation schedule, the approach of heavy weather, and other circumstances that would require a change in the ships routine or other action on their part.
    
  • Keep informed of the status and current capabilities of the engineering plant and keep the engineering officer of the watch advised concerning boiler power requirements and the operational situation so they may operate the engineering plant intelligently.
  • Carry out the routine of the ship as published in the plan of the day and other ships directives, keeping the executive officer advised of any changes that may be necessary.
  • Supervise and control the use of the general announcing system; the general, chemical, collision, sonar, and steering casualty alarms; and the whistle according to the orders of the commanding officer, tactical doctrine, and the Rules of the Road.
  • Permit no person to go aloft on the masts or stacks or to work over the side except when wind and sea conditions will not expose him or her to danger; and then only when all applicable safety precautions are observed.
  • Supervise and control all transmissions and acknowledgments on the primary and secondary tactical voice radio circuits, and ensure that proper phraseology and procedures are used in all transmissions.
  • Supervise and conduct on-the-job training for the Junior Officer of the Watch, the Junior Officer of the Deck, and enlisted personnel of the bridge watch.
  • Assume such other responsibilities as may be assigned by the commanding officer.
  • Supervise the striking of the ship's bell to denote the hours and half-hours from reveille to taps, requesting permission of the commanding officer to strike eight bells at the hours of 0800, 1200, and 2000.
  • On ships that do not station a damage control watch officer, supervise the maintenance of a log of all fittings that are in violation of the material condition of readiness prescribed. Entries will show the name and rate of the person requesting permission to open a fitting, approximate length of time to be open, and time closed. Anyone who, without permission, violates the material condition of readiness in effect shall be made the subject of an official report.
    
  • Since the OOD has such important duties, it is important to ensure that there is a clear turnover of the watch and that everyone on duty knows exactly who the current OOD is. Therefore, there is a formal method for relieving the Officer of the Deck.
  • Assume that Lieutenant Smith is the Officer of the Deck and Lieutenant Jones is his relief. Lieutenant Jones will go to the Combat Information Center (CIC) to determine any necessary actions that will be expected to occur during the watch, check the navigational track, read any orders, and determine the position of all nearby ships. Then Lieutenant Jones will report to the bridge and state to Lieutenant Smith, "I am ready to relieve you, sir." Lieutenant Smith states, "I am ready to be relieved" and will then brief Lieutenant Jones on any additional information that he should be made aware, reconfirming the information that Lieutenant Jones has previously learned from CIC. When Lieutenant Jones is fully satisfied, he then states, "I relieve you, sir." Lieutenant Smith then loudly states, "I stand relieved. Attention in the pilot house (or bridge), Lieutenant Jones has the deck." An exchange of hand salutes would also be appropriate, depending on the ship. Lieutenant Jones would then loudly announce, "This is Lieutenant Jones, I have the deck."
  • The JOOD is relieved in a similar manner as the OOD. Typically, the Junior Officer of the Deck (JOOD) has the "conn" or control of the engines and rudder. The deck and/or the conn may be assumed by the Captain simply by announcing the fact or by issuing an order to the helmsman or lee helmsman. For example, the captain may state, "I have the deck and the conn," or "I have the conn," or "Right full rudder, all ahead flank." In the latter case, someone (usually the JOOD) will announce, "The Captain has the conn." The conn may also be passed to someone else, for a particular purpose. While the Captain may assume the conn, the OOD may order the JOOD to pass him the conn, "Ensign Pulver, pass me the conn." Ensign Pulver will then state, "This is Ensign Pulver, Lieutenant Jones has the deck and the conn." Lieutenant Jones then announces, "This is Lieutenant Joes, I have the Deck and the Conn." In an emergency, the OOD may assume the conn by announcing, for example, "This is Lieutenant Smith, I have the conn. Hard right rudder, all engines ahead flank." However, in most ships, during normal underway operations, it is generally considered "poor form" to request the JOOD to pass the conn, since a good OOD would be expected to direct the JOOD without the necessity of assuming the conn.
  • These changes in deck and/or conn assumption are entered in the ship's log so it is always clear who has responsibility for the deck or conn at any time.
    
• Junior Officer of the Deck (JOOD). Principle assistant to the OOD. JOOD is in training for OOD duty. During complex maneuvers, JOOD may be positioned on the open bridge.
• Conning Officer. Gives orders to the helmsman and lee helmsman. Responsible to the OOD. In most cases, the JOOD assumes these responsibilities.
• Boatswain's Mate of the Watch (BMOW). Responsible to the OOD. Duties include:
  • Responsible for the bridge watch team. Ensures all positions are manned and relived on time and that all watch personnel are in proper uniform.
  • Makes ship announcements using 1MC, alarms, and a Bo‘son pipe.
• Signalman of the Watch (SMOW). Responsible to the OOD. Duties include:
  • Must be proficient in all types of visual communication.
  • Stays on lookout for visual signals and reports messages to OOD.
  • Relays messages received from OOD.
• Quartermaster of the watch (QMOW). Responsible to the OOD. Duties include:
  • Must be a qualified helmsman.
  • Reports temperature, barometric pressure, and weather changes to OOD.
  • Assists OOD in navigation.
  • Makes entries in Ship’s Log.
  • Executes procedures for sunrise and sunset.
    
• Helmsman. Operates the helm and is responsible to the Conning Officer. Duties include:
  • Must be qualified by the navigator as a helmsman.
  • Makes steering correction using ship’s wheel as ordered.
  • Repeats orders word for word.
  • Reports completion of order.
• Lee Helmsman. Operates the Engine Order Telegraph (EOT) and is responsible to the Conning Officer. Duties include:
  • Qualified to relieve the Helmsman.
  • Rings up speed changes to engine room as ordered.
  • Repeats orders word for word.
  • Reports conformation of order received from engine room.
• Messenger. Relays messages to and from the OOD Duties include:
  • Knowing where to go to find key personnel
  • Deliver message directly and quickly.
  • Repeat message exactly.
  • Message for captain or admiral should be delivered to his or her orderly.
  • Report delay in delivery and reason for delay to OOD.
  • Report to sender the delivery or the message.
• Lookouts. Located at various points outside the bridge. They scan the surface and air for contacts and report any contacts to the OOD on the bridge using sound-powered phones. Due times of low visibility, extra lookouts are posted.
  

Bridge Equipment

• Helm Unit. Mechanical device used to steer the ship. Helm consists of:
  • Wheel. The ship’s wheel is on the steering control console and has controls and indicators required to control the course of the ship. The ship is steered by the helmsman.
  • Mechanical Helm Indicator. Indicates the number of degrees the wheel is turned. Usually this is the same number of degree as the rudder’s position.
  • Rudder Angle Indicator. It has a dual purpose. During normal steering situations, it shows the actual angle of the rudder which usually lags the wheel angle indicator by about 2 degrees because of the time required for the steering mechanism to operate. For emergency steering, this instrument becomes useful in transmitting visual orders to the helmsman who is located in the after-steering compartment. By operation of the control knob, the rudder order is displayed on the instrument when the pointer marked "ORD" is moved to the desired rudder angle. The order is displayed in after-steering on another rudder angle order indicator-transmitter, from which the after helmsman receives orders. A push switch next to the rudder angle order indicator-transmitter on the bridge operates a bell in after-steering to call the helmsman's attention to a change in rudder angle.
  • "Steer by" Indicator. It displays the course to be steered by the helmsman. It differs mainly from the ship's course indicator in that its dials are positioned from a synchro transmitter located in sonar, CIC, or other Weapons Control Station, which allows these stations to to steer without having to use a means of voice transmission.
    
  • Steering Cable Selector Switch. Allows selection of hydraulic, electric, gyro, or aft-steering.
  • Steering Casualty Alarm. A means by which the bridge can warn the after-steering station that a steering emergency has occurred and that steering must be controlled from after-steering.
  • Attention Bell. Located on the steering control, it is used when rudder indicators do not match up; the bell rings in after steering.
  • Course Ordered Indicator. Provides a means of electrically transmitting rudder angle orders from the steering control console to the steering gear room when the ship is being steered from there.
  • Magnetic Compass. Consists of a magnetized compass needle attached to a circular compass card, usually about 7-1/2 inches in diameter. The card and needle are supported on a pivot that is set in a cast bronze bowl filled with a petroleum distillate fluid. The card remains stationary, pointing at the magnetic pole which is a north-south line lined up with the north-south (magnetic) directions on the Earth.
  • Gyrocompass. Points constantly to the true north rather than the magnetic north pole. It may have a slight mechanical error, but this error is computed easily and remains constant for any heading so that it does not interfere in any way with the instrument's practical value.
  • Auto Pilot. Device used to keep the ship at a predetermined speed and course automatically.
  • Portable Steering Control Unit (PSCU). When a ship losses control of steering at the helm, the PSCU can be rigged to send throttle signals to engineering and rudder commands to after-steering.
• Engine Order Telegraph (EOT). A device equipped with separate handles for port and starboard engines that are used to order speed changes. It is manned by the lee helmsman. Using different RMS’s for each engine may also be used to nay course changes.
  • Bell Selector and Hand Lever. Speed is selected on the telegraph by the Lee Helmsman on order from the conn. The engine room watch sets the engine throttle for the same speed and notifies the bridge by moving an answering pointer to the same sector. When bridge’s pointer indicates the throttle change has been made, the helmsman reported it to the conn.
  • RPM Enunciators. Enables the bridge to make minor changes in speed by ordering the engine rooms to increase or decrease RPM of the propeller.
  • Attention Bell. Used mostly when speed changes are not answered by the engine room.
    

Bridge Alarms

• General Alarms. Alarms are listed in order of priority. A higher priority alarm will override a precious alarm of lesser priority.
  • Collision. Sounded in event of impending collision. Has precedence over all other bridge alarms. Switch is color coded YELLOW and shaped as a STAR. Set by the BOOW upon orders from OOD.
  • Chemical. Sounded when chemical attack is eminent or detected. Switch is color coded GREEN and shaped as a SQUARE. Set by the BOOW upon orders from OOD.
  • General. Sounded to call crew to general quarters. Switch is color coded RED and shaped as a CIRCLE.
  • Helo Crash. Sounded in event of impending or actual helicopter crash on the flight deck. Switch is color coded GRAY and shaped as a LEVER. Set by the BOOW upon orders from OOD.
• FZ (Security). Consists of a bell and indicator lamp which provides an audible and visual indication of entry into a special weapons magazine when the system is energized.
• Gyro. Provides an audible indication of a casualty in the gyro system.
• Magazine High Temperature. Provides an audible and visual indication of high temperatures in a magazine.
• Magazine Flooding. Provides an audible and visual indication of flooding in a magazine.
• Sonar Contact. When initiated by sonar control, it alerts the bridge and CIC of a contact.
• Engineering Casualty. The 26 MC is used to provide direct voice communications with the bridge in case of a casualty.
• Missile Warning Alarm. Sounded when the fire control tracking radar detects a high speed inbound target.
• Carbon Dioxide Release Alarm (FR). Audible and visual alarm warning of carbon dioxide presence in specific compartments, such as the paint stowage locker, missile magazine, flammable storage areas, etc.
• Flooding Alarm (FD). Audible warning of flooding in specific compartments.
  

Information and Display Equipment

• Gyrocompass Repeater. Displays the indications of the master gyrocompass. It is also used in taking bearings on objects outside the ship.
• Magnetic Compass. Consists of a magnetized compass needle attached to a circular compass card, usually 7-1/2 inches in diameter. The card and needle are supported on a pivot that is set in a cast bronze bowl filled with a petroleum distillate fluid. Marked on the compass bowl is a line, called the lubber's line, which agrees with the fore-and-aft line of the ship or boat. By reading the compass card direction, lined up with the lubber's line, you can tell the direction the ship is heading.
• Radar Repeater. Displays radar returns from primary radars.  
• Anemometer Repeater. Provides display of wind speed and direction. The upper dial of the repeater is graduated in 10-degree intervals and shows the apparent relative direction from which the wind is blowing. The lower dial indicates the apparent wind speed (true wind speed when the ship is stationary).
• Inclinometer. Indicates the amount of pitch and roll of the ship.
• Shaft Tachometer. Indicates shaft RPM.
• Status Boards. Provides a listing of current tactical information.
• Position Indicator. A repeater unit that provides a display of the ship's target and tactical information.
• Fathometer. Used primarily for navigational purposes as an aid in gathering depth information for oceanographic topography and occasionally as a sonar contact classification aid.
• LORAN (Long Range Navigation). Enables navigator to determine ship's position by means of radio signals broadcast by stations of known position.
• SATNAV (Satellite Navigation). A global, all-weather navigation system that allows navigators to obtain a fix to within a fraction of a mile, night or day, in all parts of the world.
• OMEGA. Enables navigators to obtain reliable positions comparable in accuracy to LORAN on a worldwide and nearly continuous basis. It uses only eight transmitting stations.  
• Bridge Wing Display Unit (BWDU). Provides each bridge wing with a readout of rudder angle, gyro repeater, propeller pitch, and RPM indicator.
• Barometer. Measures atmospheric pressure.
• Navigation Light Panels. Provides an audible and visual signal when the primary filament burns out in any one of the five running lights, and automatically switches to the second filament so the lights remain in service.
  

Communications Equipment

• Secure/Unsecure Radiotelephone (R/T) Handsets and RHMS Controls. Provide secure voice communications between various units of the fleet. Unsecured provides voice or teletype communications between various units through UHF, VHF and HF transceivers.
• Sound-powered Phones and Growlers. Primary source of shipboard communications since they require no external power for operation.
• Ship's Whistle. Used primarily for warning other ships of your own ship's intentions or executions. Two blasts for port turn and one blast for starboard turn, five or more blasts for an emergency.
• 1MC General Announcing System. Central amplified announcing system designed to furnish amplified voice communications and alarm signals to the various speaker systems over the entire ship. Master control that provides the microphone and switches for the various receiving groups is located on bridge, quarterdeck, and AA (Anti-Aircraft) stations.
• 21MC. CO's command circuit which provides communications with various command stations such as CIC, main control, etc.
• X1J Sound Power Phone System. Auxiliary ship administration circuit.
• Voice Tubes. Used as a means of communication between secondary conn and the bridge. On smaller ships, it is used for communications between the bridge and CO's cabin.
• Pneumatic Tubes. Provide for communication between radio, CIC, bridge, and other strategic locations by means of written messages placed in shuttles that move through tubes by using vacuum. They are used since there is no possibility of message interception.
• Call Bell/"E" Call System. Various circuits for notification of communications.
• Ship's Service Telephone. Basic hard wired dial telephone system used throughout the ship via a telephone switchboard.  
• Underwater Telephone (Gertrude). Use primarily during EMCON (no electronic emission) conditions for communications between various units, with a range of 3 to 4 miles.