Comprehensive Guide to Ship Fundamentals, Watchstations, and Navigation

Structural Components and Hull Reference Terminology

• Primary Structural Components:

  • Keel: The spine of the ship, running continuously along the centerline from bow to stern.

  • Frames: The structural ribs of the ship, fastened directly to the keel and numbered sequentially starting from the bow.

  • Longitudinal Frame: Structural member running parallel to the keel from the bow to the stern.

  • Plating / Hull: The outer skin of the vessel, comprising the outer plating, deck plating, and inner bottom plating.

  • Bilge: The lowest interior point on the ship, situated directly beneath the engineering spaces. It is slightly bowl-shaped to collect fuel, oils, or other fluids that drip from machinery.

  • Stem: The forward continuation of the keel extending upwards at the bow.

  • Stern Post: The aft continuation of the keel extending upwards at the stern.

  • Mast: The vertical structure serving as a mounting platform for radar, navigation, and telecommunication equipment.

  • Rudder: The primary hydrodynamic surface used to steer the ship by directing water flow.

  • Propeller (Screw): The primary mechanical device providing propulsion to drive the ship through the water.

• Hull Reference Points and Relative Directions:

  • Bow: The forward-most section of the ship.

  • Stern: The aft-most section of the ship.

  • Forward: Direction moving toward the bow.

  • Aft: Direction moving toward the stern.

  • Inboard: Direction moving toward the longitudinal centerline of the ship.

  • Outboard: Direction moving away from the centerline toward the exterior sides.

  • Amidships: The central section of the ship along its length.

  • Port Side: The entire left side of the vessel when facing forward towards the bow.

  • Starboard Side: The entire right side of the vessel when facing forward towards the bow.

  • Port Bow / Starboard Bow: Relative forward sectors on the port and starboard sides.

  • Port Beam / Starboard Beam: Directions directly perpendicular ($90^\circ$) to the ship's centerline on the port and starboard sides.

  • Port Quarter / Starboard Quarter: Relative aft sectors on the port and starboard sides.

• Decks and Exterior Reference Terms:

  • Main Deck ($1\text{st}\text{ Deck}$): The uppermost sheltered deck running continuously along the entire length of the vessel.

  • Weatherdeck: Any portion of the main deck or higher levels exposed directly to the outside weather.

  • Lifelines: Protective lines installed along the edges of the main deck and weatherdecks to prevent personnel from falling overboard.

  • Forecastle: The portion of the main deck located forward of the main mast.

  • Fantail: The portion of the main deck located at the extreme aft end of the ship, frequently serving as the flight deck.

  • Waterline: The horizontal line on the hull where the surface of the water meets the ship.

  • Freeboard: The vertical distance measured in feet from the waterline up to the main deck.

  • Length Overall ($LOA$): The total end-to-end physical length of the ship from the tip of the bow to the stern.

  • Length at the Waterline ($LWL$): The total horizontal length of the ship's hull immersed under the water at the waterline.

  • Draft: The vertical distance measured in feet from the waterline down to the lowest point of the keel. Draft determines the minimum water depth required for the ship to float and changes dynamically as the ship consumes or loads fuel, stores, or ammunition.

  • Trim: The operational balance relationship between the fore and aft draft. Status is described as "in trim", "down by the bow", or "down by the stern".

  • List: The transverse inclination or balance of the vessel side-to-side. Status is described as "listing port" or "listing starboard".

• Internal Structural Organization:

  • Deck: Nautical term applied to all interior horizontal floors located below the main deck ($1\text{st}\text{ Deck}$, $2\text{nd}\text{ Deck}$, $3\text{rd}\text{ Deck}$, $4\text{th}\text{ Deck}$, $5\text{th}\text{ Deck}$).

  • Level: Nautical term applied to all interior horizontal floors located above the main deck ($01\text{ Level}$, $02\text{ Level}$, $03\text{ Level}$, $04\text{ Level}$).

  • Compartments: Nautical term for rooms aboard a ship.

  • Bulkhead: Nautical term for vertical interior structural walls.

  • Overhead: Nautical term for interior structural ceilings.

Compartment Labeling System and Decoding

• Structure of Compartment Bullseyes:

  • Every compartment aboard a naval vessel features a standardized alphanumeric identification label (known as a bullseye) posted on or near its entryways.

  • Example Compartment Label: 2-123-1-L FR 123-130 OD DIV

  • Deck/Level Code (2): Identifies the vertical deck or level location. Numerical values ($1, 2, 3\dots$) signify decks below the main deck. Values preceded by a zero ($01, 02, 03\dots$) signify levels above the main deck.

  • Starting Frame Number (123): Specifies the forward-most structural frame boundary of the compartment.

  • Centerline Position (1): Indicates the compartment position relative to the ship's centerline. Even numbers designate spaces located on the Port side; odd numbers designate spaces located on the Starboard side. Larger numbers represent greater distance from the centerline.

  • Usage/Purpose Letter (L): Single or double letter designation defining the functional classification of the space.

  • Frame Span (FR 123-130): Explicitly details the bounding frame span from the first frame to the last frame.

  • Responsible Division (OD DIV): Designates the shipboard division assigned maintenance and operational ownership of the space.

• Standard Compartment Classification Codes:

  • A: Supply stowage space, store room, or refrigerated storage compartment.

  • AA: Cargo hold or dry cargo storage area.

  • C: Ship control centers (e.g., Bridge, Combat Information Center [CIC]).

  • E: Engineering propulsion and auxiliary spaces.

  • L: Living spaces (including berthing areas, mess decks, and staterooms).

  • M: Ammunition handling spaces and magazine lockers.

  • Q: Miscellaneous compartments not explicitly covered by other letter codes.

  • T: Vertical access trunks and escape trunks.

  • V: Void spaces and empty structural tanks.

  • Special letter codes are also designated for fuel and liquid storage tanks.

5 Fundamentals and Coordinate Systems

• The Terrestrial Sphere:

  • North Pole: The northernmost geographic point on Earth ($90^\circ\text{N}$).

  • South Pole: The southernmost geographic point on Earth ($90^\circ\text{S}$).

  • Equator ($0^\circ$): The great circle dividing the Earth into the Northern and Southern Hemispheres

  • Prime Meridian ($0^\circ$): The reference meridian dividing the Earth into the Eastern and Western Hemispheres.

  • Latitude (Parallels): Measures distance North or South of the Equator in degrees, minutes, and seconds. Key reference parallels include:

  • Arctic Circle: $66^\circ 34'\text{N}$

  • Tropic of Cancer: $23^\circ 26'\text{N}$

  • Equator: $0^\circ$

  • Tropic of Capricorn: $23^\circ 26'\text{S}$

  • Antarctic Circle: $66^\circ 34'\text{S}$

  • Longitude (Meridians): Measures distance East or West of the Prime Meridian in degrees, minutes, and seconds. Degrees of longitude are always written using a 3-digit format (e.g., longitude \n\lambda = 076^\circ 17' 45''\text{W}, compared to latitude $Q = 37^\circ 50' 00''\text{N}$).

• Expressions of Direction:

  • True Direction ($^\circ\text{T}$): Angular distance measured clockwise from $0^\circ$ to $360^\circ$ relative to TRUE NORTH between two points on the Earth's surface.

  • Relative Direction ($^\circ\text{R}$): Angular distance referenced directly from the ship's longitudinal centerline (SHIP'S BOW).

  • Magnetic Direction ($^\circ\text{M}$): Angular distance referenced to MAGNETIC NORTH, which varies geographically based on Earth's magnetic forces.

  • Compass Direction ($^\circ\text{PSTGC}$ / per steering compass): Angular distance referenced to the north axis of the physical COMPASS CARD. Differs from True Direction due to combined compass error (variation plus deviation).

Compass Systems and Navigational Calculations

• Magnetic Compass Operations:

  • Readings are taken in degrees Magnetic ($^\circ\text{M}$).

  • Advantages: Inexpensive, self-contained, structurally simple, highly durable, and does not require electrical power.

  • Disadvantages: Magnetic North is non-fixed and fluctuates geographically; requires complex, regular physical adjustments.

  • Variation ($V$): The angular difference between True North and Magnetic North at any specific geographic location.

  • Calculating Variation Changes: Compass roses printed on nautical charts specify the variation for a base year and the annual rate of increase or decrease.

  • Example Calculation: Chart rose states Variation = $4^\circ 15'\text{W}$ in 1985 with an Annual Decrease of $15'$.

    • Variation in 1986: $4^\circ 15'\text{W} - 15' = 4^\circ 00'\text{W}$.

    • Variation in 1987: $4^\circ 00'\text{W} - 15' = 3^\circ 45'\text{W}$.

  • Deviation ($D$): Magnetic error induced in a compass by localized magnetic fields aboard the vessel (e.g., steel hull structure, electronics).

  • Deviation Table (Compass Table): A matrix indicating specific magnetic deviation based on the ship's magnetic heading and whether shipboard degaussing systems are active (ON) or inactive (OFF).

• Gyro Compass Operations:

  • Advantages: Aligns directly to True North ($^\circ\text{T}$); independent of magnetic fields and local geographical variations.

  • Disadvantages: Requires uninterrupted electrical power; requires extensive calibration and warm-up time if power is lost; complex electrical system needing specialized maintenance.

  • Operational Applications: Primary heading reference for shipboard Navigation and Weapons Systems.

• Converting Directional Values:

  • True to Compass Conversion Formula (Truly Valiant Marines Don't Cry At Weddings):

  • Order: True ($T$), Variation ($V$), Magnetic ($M$), Deviation ($D$), Compass ($C$).

  • Mathematical Rule: Add West ($A$ $W$) when converting from True to Compass (subtract East).

  • Compass to True Conversion Formula (Can Dead Men Vote Twice At Elections):

  • Order: Compass ($C$), Deviation ($D$), Magnetic ($M$), Variation ($V$), True ($T$).

  • Mathematical Rule: Add East ($A$ $E$) when converting from Compass to True (subtract West).

  • Navigation Conversion Scenarios:

  • Scenario 1: A ship loses its gyro compass while steering $110^\circ\text{T}$. The Navigator orders a turn to $125^\circ\text{T}$. Variation is $8^\circ\text{W}$ and Deviation is $2.5^\circ\text{E}$. Calculate the course per steering compass ($C$) to order.

    • Step 1: Target True Course $T = 125^\circ\text{T}$.

    • Step 2: Apply Variation $V = 8^\circ\text{W}$. True to Compass requires adding West: $125^\circ + 8^\circ = 133^\circ\text{M}$.

    • Step 3: Apply Deviation $D = 2.5^\circ\text{E}$. Subtract East: $133^\circ - 2.5^\circ = 130.5^\circ\text{PSTGC}$.

    • Ordered Steering Course: $130.5^\circ\text{PSTGC}$.

  • Scenario 2: A ship is heading $127^\circ\text{PSTGC}$. Variation is $4^\circ\text{W}$ and Deviation is $2^\circ\text{W}$. Calculate the True Heading ($T$).

    • Step 1: Starting Compass Course $C = 127^\circ\text{PSTGC}$.

    • Step 2: Apply Deviation $D = 2^\circ\text{W}$. Compass to True requires subtracting West: $127^\circ - 2^\circ = 125^\circ\text{M}$.

    • Step 3: Apply Variation $V = 4^\circ\text{W}$. Subtract West: $125^\circ - 4^\circ = 121^\circ\text{T}$.

    • True Heading: $121^\circ\text{T}$.

Shipboard Watchteam Organization

• Bridge Watchteam Duties:

  • Officer of the Deck (OOD): Overall in charge of the Bridge. Reports directly to the Commanding Officer (CO) for safe navigation and general ship operations; to the Executive Officer (XO) for executing the ship's daily routine; and to the Navigator upon sighting navigational landmarks. Issues rudder or engine modification orders through the Conning Officer. Coordinates cross-departmental operations between the Bridge, Combat Information Center (CIC), and Central Control Station (CCS).

  • Junior Officer of the Deck (JOOD / OOD U/I): An OOD under instruction; serves as principal assistant to the OOD. Duties are to become proficient in OOD responsibilities and perform tasks as directed by the OOD.

  • Conning Officer (Conn): Responsible for safe vessel maneuvering. Issues engine and rudder commands directly to the Helmsman and Lee Helmsman.

  • Quartermaster of the Watch (QMOW): Maintains the navigational picture for the OOD. Serves as the Navigator's direct representative when the Navigator is off the Bridge.

  • Boatswain's Mate of the Watch (BMOW): Enlisted assistant to the OOD for executing the daily routine (Plan of the Day) and passing word across the ship over the 1MC. Oversees the watch rotation, instruction, behavior, and appearance of enlisted watchstanders.

  • Helmsman: Executes rudder commands issued by the Conn.

  • Lee Helmsman: Executes engine orders issued by the Conn.

  • Lookouts: Assists the OOD in maintaining continuous $360^\circ$ situational awareness while underway by reporting surface and air contacts.

  • Navigator and Piloting Team: Provides continuous positional fixes and expert navigational counsel.

• Combat Information Center (CIC) Watchteam Duties:

  • Tactical Action Officer (TAO): Senior watchstander in the CIC and direct representative of the Commanding Officer for employing weapons systems. Directs CIC watchstanders and guides the OOD in overall tactical employment and defense of the ship.

  • Combat Information Center Watch Officer (CICWO): Supervises all watchstanders in the CIC. Ensures all combat systems, sensors, and communication circuits are operating properly. Provides recommendations to the OOD regarding station keeping, collision avoidance, and safe maneuvering.

  • RADAR Navigation Team: Maintains a backup navigation plot to support the QMOW or Piloting Team. Operates independent RADAR and VMS nodes in CIC to calculate contact management and navigation solutions. Reports to the CICWO.

  • Combat Coordinators: Assist the TAO in maintaining tactical awareness and managing sensor and weapons systems. Report to the CICWO for navigation relays. Divided by warfare area:

  • Surface Warfare Coordinator (SUWC): Manages the surface tactical picture and surface weapons employment.

  • Anti-Air Warfare Coordinator (AAWC): Manages the air tactical picture and surface-to-air defense systems.

  • Anti-Submarine Warfare Coordinator (ASWC): Manages the subsurface tactical picture and subsurface weapons employment.

• Engineering Central Control Station (CCS) Watchteam Duties:

  • Engineering Officer of the Watch (EOOW): In charge of the operation of the ship's engineering plant while underway. Reports directly to the Chief Engineer for safe engineering plant operation, and directly to the OOD for engineering plant status and casualties.

  • Propulsion and Auxiliaries Control Console Operator (PACC): Controls the main propulsion plant and remotely operates major propulsion equipment. Reports to the EOOW.

  • Electrical Plant Control Console Operator (EPCC): Controls the ship's electrical plant, overseeing electrical load management and freshwater distribution. Reports to the EOOW.

  • Equipment Monitors: Roving watchstanders positioned throughout the plant who inspect machinery, fuel, and oil levels. Report directly to the EOOW and serve as the initial line of defense for Damage Control.

Navigation, Distance Measurement, and Sensor Equipment

• Bearing Measurement Devices:

  • Azimuth Circle: Measures direction (bearing) to geographic objects or targets. Mounted on the centerline pelorus inside the pilot house.

  • Telescopic Alidade: Measures direction (bearing) to target objects. Mounted on the bridge wings; utilizes optical magnification to allow watchstanders (primarily lookouts) to clearly view targets down a target bearing.

• Meteorological and Safe Water Equipment:

  • Barometer: Measures atmospheric pressure. High barometric pressure indicates fair weather conditions; low or rapidly dropping pressure indicates adverse weather conditions.

  • Voyage Management System (VMS): Electronic charting software utilized by the OOD and QMOW to keep the vessel in safe water, plot routes, and maintain safe geographic boundaries.

  • Fathometer: Employs SONAR acoustic pulses to measure water depth from the ship's keel to the ocean floor, verifying safe depth clearances.

• Distance Measurement Equipment:

  • RADAR: Transmits radio frequency waves into the air and measures the time interval required for the echo to return, converting time into exact target range.

  • Stadimeter: Utilizes dual logarithmic scales to determine distance to objects of known height. Highly accurate at ranges under $2000\text{ yards}$, but experiences diminished accuracy at longer ranges.

  • Laser Rangefinder: Uses laser light pulses traveling at a velocity of $186,000\text{ miles/second}$ for rapid distance calculations. Primary choice for short-range measurements, such as aligning two ships alongside during Underway Replenishment (UNREP).

  • Sextant: Determines distance to objects of known height using trigonometric calculations or conversion tables (similar in function to a stadimeter).

• Combat Information Center Radar Sensors:

  • General RADAR: Provides duplicate radar inputs to the CIC team to maintain a complete Recognized Maritime Picture (RMP) backing up the Bridge.

  • SPY Radar: Phased-array air and missile defense radar used by the AAWC to detect, track, identify, and engage aircraft or missile threats.

  • SPQ-9B Radar: Horizon-scanning radar performing simultaneous, automated air and surface target detection out to the horizon.

Internal Communications and Specialized Engineering Spaces

• Internal Communication Systems:

  • NET 15: Common internal communications circuit monitored simultaneously by the Bridge, CIC, and CCS. Pertinent operational data is passed over NET 15 to maintain cross-station situational awareness.

  • 1MC: The primary, strictly controlled internal general announcing system used to pass official shipboard business to the entire crew. Primary control of the 1MC rests with the Bridge.

• Specialized Engineering Spaces and Damage Control:

  • Repair Lockers: Stations located throughout the vessel storing essential damage control equipment.

  • Emergency Response: During a casualty (in-port or at sea), either the Flying Squad or At-Sea Fire Party responds to the locker to don protective gear and fight the casualty.

  • Locker Officer: Plots casualty progress on Damage Control (DC) Plots and maintains continuous communication with response teams.

  • Aft Steering (After Steering): The local machinery space housing the steering units that physically move the rudders.

  • Steering Redundancy: In the event of a bridge steering casualty, watchstanders can take local manual control from multiple control stations inside Aft Steering to safely steer the vessel.

Principles of Shiphandling, Forces, and Hydrodynamics

• Uncontrollable Environmental Forces:

  • Forces that cannot be controlled by the shiphandler but must be accounted for or exploited: Wind, Sea State, Current, and Shallow Water Effect / Squat.

  • Force Ratios: Current forces exert a far greater physical impact on ship movement than wind. The impact ratio is approximately $10:1$ (wind speed to current speed), meaning a $1\text{ kt}$ current influences the ship to the same extent as $10\text{ kts}$ of wind.

• Controllable Forces:

  • Forces directly manipulated by the shiphandler: Mooring Lines, Anchors, Tugs, Engines (Propellers), and Rudders.

• Propeller Mechanics and Side Force:

  • Engine Configurations: Most naval ships feature $2$ propellers (twin screw); aircraft carriers and patrol craft utilize $4$ propellers.

  • Side Force (Paddlewheel Effect): Causes the stern of the ship to walk sideways in the direction of propeller rotation. The lower the vessel's speed through the water, the more pronounced the side force effect becomes.

  • Controllable Pitch Propeller (CPP):

  • Installed on all US Navy Gas Turbine and Diesel surface vessels (e.g., DDG, CG, LSD, LPD).

  • Eliminates the need to reverse shaft direction for astern movement by rotating individual propeller blade pitch angles.

  • Under normal operating conditions, CPP-equipped ships are completely unaffected by Side Force.

  • Fixed-Pitch Propeller Rotation Effects:

  • Port Engine Ahead: Counter-Clockwise (CCW) rotation; stern walks to the left, bow turns to the right.

  • Port Engine Back: Clockwise (CW) rotation; stern walks to the right, bow pulls to the left.

  • Starboard Engine Ahead: Clockwise (CW) rotation; stern walks to the right, bow turns to the left.

  • Starboard Engine Back: Counter-Clockwise (CCW) rotation; stern walks to the left, bow pulls to the right.

• Rudder Operations and Hydrodynamic Forces:

  • Controls heading by deflecting water flow to move the stern. Requires continuous water flow over the rudder surface, typically provided by propeller discharge current.

  • Hydrodynamic Wing Effect: Water flowing across a deflected rudder produces a High Pressure Area on one side and a Low Pressure Area on the other, creating transverse Rudder Force.

• Mechanics of the Pivot Point:

  • Turning Dynamics: Vessels do not steer like automobiles by following front wheels; vessels turn by swinging their stern in the direction opposite to the intended turn around a Pivot Point.

  • Pivot Point Locations:

  • Ahead Movement ($++$ speed): Pivot Point shifts forward towards the bow.

  • Astern Movement: Pivot Point shifts aft towards the stern.

  • Dead in Water (DIW): Pivot Point sits near amidships.

• Kinematic Metrics:

  • Heading (HDG) vs. Course Over Ground (COG):

  • Heading (HDG): The physical direction in which the ship's bow is pointed.

  • Course Over Ground (COG): The actual path of travel relative to the Earth, accounting for environmental forces causing the vessel to "crab walk".

  • Speed Through Water (STW) vs. Speed Over Ground (SOG):

  • Speed Through Water (STW): Velocity relative to the surrounding water column. Measured by pit swords, pit logs, impeller logs, or shaft RPM.

  • Speed Over Ground (SOG): Actual movement speed relative to the Earth. Measured fix-to-fix via GPS or Doppler Speed Log. SOG is used for accurate route calculations, travel duration estimates, and Optimum Track Ship Routing (OTSR) reports.

Ship Maneuvering Tactics: Twists and Pier Evolutions

• Executing Engine Twists:

  • Definition: Maneuver using opposing engine thrust directions in combination with full rudder to turn the vessel in place around its pivot point while maintaining a stationary position.

  • Starboard Twist Execution: Order Right Full Rudder, Port Engine Ahead 1/3, Starboard Engine Back 1/3.

  • Port Twist Execution: Order Left Full Rudder, Starboard Engine Ahead 1/3, Port Engine Back 1/3.

  • Memory Aids for Twists:

  • Bicycle Method: Pretend to hold bicycle handlebars. Turning the handlebars right (Starboard Twist) moves your left hand forward (Port Engine Ahead) and right hand back (Starboard Engine Back).

  • Wheelchair Method: Imagine sitting stationary in a wheelchair. Turning left in place (Port Twist) requires pulling the left wheel back (Port Engine Back) and pushing the right wheel forward (Starboard Engine Ahead).

  • Tactical Applications: Used during mooring and unmooring, special evolution maneuvering, and maintaining station in tight waters.

• Pier Handling Scenarios:

  • Scenario 1 (Benign Conditions - No Wind / No Current):

  • Approach the pier at a shallow angle ($10^\circ$ to $20^\circ$ off the pier heading).

  • Stop engines and drift closer.

  • Put rudder over away from the pier to align the ship parallel.

  • Back down engines as required to eliminate forward headway.

  • Scenario 2 (ON-Setting Environmental Conditions - Wind/Current pushing onto pier):

  • Bring the ship to a complete stop parallel to the pier at a greater range than under benign conditions.

  • Allow the environmental wind or current to push the vessel laterally onto the pier.

  • Use engines to adjust fore-and-aft position along the pier.

  • Scenario 3 (OFF-Setting Environmental Conditions - Wind/Current pushing off pier):

  • Approach at a higher speed with a steep approach angle.

  • Pass the bow line to the pier as early as possible.

  • Execute an engine twist to bring the stern in toward the pier.

  • Kill forward headway by backing the outboard engine.

Standard Exterior Navigation Lighting Configurations

• Masthead Light:

  • Arc of Visibility: Displays an unbroken light over an arc of $225^\circ$ from dead ahead to $22.5^\circ$ abaft the beam on both port and starboard sides.

  • Color: White.

  • Position: Fixed on the fore-and-aft centerline. (Note: On smaller motorboats, it may be mounted on a short pole on top of the cabin or stem).

• All-Round Light:

  • Arc of Visibility: Displays an unbroken light across a full $360^\circ$ horizon.

  • Color: White.

  • Position: Mounted where visible from all directions.

• Towing Light:

  • Arc of Visibility: Displays an unbroken light over an arc of $135^\circ$.

  • Color: Yellow.

  • Position: Placed as close as possible to the stern.

• Port Sidelight:

  • Arc of Visibility: Displays an unbroken light over an arc of $112.5^\circ$ from dead ahead to $22.5^\circ$ abaft the beam on the port side.

  • Color: Red.

  • Position: Mounted on the port side forward area of the vessel.

• Starboard Sidelight:

  • Arc of Visibility: Displays an unbroken light over an arc of $112.5^\circ$ from dead ahead to $22.5^\circ$ abaft the beam on the starboard side.

  • Color: Green.

  • Position: Mounted on the starboard side forward area of the vessel.

• Sternlight:

  • Arc of Visibility: Displays an unbroken light over an arc of $135^\circ$.

  • Color: White.

  • Position: Placed as close as possible to the stern of the vessel.

Deck Seamanship: Lines, Fittings, Ladders, and Safety Equipment

• Rope and Line Classifications:

  • Rope: General term covering all fiber and wire line. Manufactured from natural fiber, synthetic fiber, wire, or combinations.

  • Line: Rope that has been purposely sized, cut, spliced, or assigned a operational function aboard ship. Measured by circumference.

  • Material Types:

  • Natural Fiber: Manila, Cotton, Hemp.

  • Synthetic Fiber: Nylon, Kevlar (Aramid), Polyester, Polypropylene.

  • Construction Patterns: Braided, Plaited, Twisted.

• Mooring Lines and Numerical Designations:

  • Line 1 (Bow Line): Tends from the bow; controls lateral distance from pier.

  • Line 2 (Aft Bow Spring Line): Tends aft from the bow area; controls forward movement.

  • Line 3 (Forward Bow Spring Line): Tends forward from the bow area; controls aft movement.

  • Line 4 (Aft Quarter Spring Line): Tends aft from the quarter area; controls forward movement.

  • Line 5 (Forward Quarter Spring Line): Tends forward from the quarter area; controls aft movement.

  • Line 6 (Stern Line): Tends from the stern; controls lateral distance from pier.

  • Functional Line Groups:

  • Breast Lines: Run at right angles ($90^\circ$) from the ship to the pier; control lateral distance.

  • Spring Lines: Tend forward or aft along the pier; control longitudinal fore-and-aft movement.

• Line Terminology:

  • Small Stuff: Line or rope measuring less than $1\frac{3}{4}\text{ inches}$ in circumference.

  • Tattletale: Small natural fiber line spliced into a synthetic mooring line to indicate working load strain.

  • Hawser: Heavy line exceeding $5\text{ inches}$ in circumference used for towing or mooring.

  • Bight: A loop formed in a line or chain.

  • Bitter End: The unattached free end of a line, wire, chain, or cable.

  • Eye: A permanently spliced loop at the end of a line.

  • Marlinspike: A tapered steel tool used in splicing wire rope.

  • Fid: A tapered wooden tool used in splicing fiber line.

  • Coil: Laying down line in vertical circular turns.

  • Flemish: Coiling line flat on the deck in a tight spiral.

  • Fake Down: Laying line out flat on deck in long parallel bights.

  • Heaving Line: Weighted light line thrown across to a pier or ship.

  • Monkey Fist: A weighted knot woven at the end of a heaving line.

  • Shot Line: Light nylon line fired across using a line-throwing gun.

• Mooring Protective Equipment:

  • Rat Guards: Circular metal shields secured around mooring lines to prevent rodents from coming aboard.

  • Chafing Gear: Protective canvas wrapped around mooring lines at high-friction contact points to prevent wear.

• Line Fittings and Deck Hardware:

  • Cleat: Metal fitting consisting of a double-ended pair of horns used to secure a line or wire.

  • Bitts: Pairs of heavy vertical cylinders used to secure lines led through chocks.

  • Bollard: Strong cylindrical post on a pier over which mooring line eyes are dropped.

  • Chock: Smooth-surfaced heavy fitting through which mooring lines are routed.

  • Padeye: A metal plate with an eye attached to the deck structure to distribute load.

  • Capstan: Powered vertical rotating drum used to haul in heavy lines during mooring and anchoring.

• Shipboard Ladders:

  • Jacob's Ladder: Temporary flexible rope ladder with wooden/metal rungs rigged over the side.

  • Pilot's Ladder: Flexible portable ladder constructed of metal; sturdier than a Jacob's ladder.

  • Sea Ladder: Rigid portable ladder rigged directly to the ship's side.

  • Accommodation Ladder: Rigid, inclined stair system rigged to the side of the ship to allow boarding while moored or anchored.

• Safety and Life Saving Equipment:

  • Life Raft: In emergency abandon-ship situations, provides shelter, rations, and paddling capability for survival.

  • MK 1 Life Preserver: Modern vest-style life preserver issued to flight deck personnel; color-coded by watchstation.

  • Kapok Life Preserver: Standard orange buoyant life preserver readily available to ship's crew.

  • Life Ring: Buoyant ring thrown overboard to provide immediate flotation to a person in the water.

  • Emergency Position Indicating Radio Beacon (EPIRB): Emergency transmitter that broadcasts a continuous radio distress signal to assist Search and Rescue (SAR) teams in locating survivors.