NSS Exam

Purpose and Organization of the underway bridge watch

The underway bridge watch's purpose is to ensure safe navigation and effective management of the vessel while at sea. This involves monitoring instruments, communicating with crew, and adhering to navigation protocols.

Commanding Officer

responsible for the safe nav of the ship,per the NAVDORM and ship’s nav bill, ensure that the nav team is using all available means to fix or establish the ships position

executive officer

• The XO will assist the Navigator and Navigation Team during all restricted water transits, unless otherwise directed by the CO. 

Navigator

NAV is designated by and is responsible to the CO for the safe navigation of the ship

Must be a graduate of surface warfare officer school

maintain the ships navigation bill

prepare Co’s night orders

Officer of the Deck

the CO’s direct representative on the bridge

prepare for and formally relieve the watch

leadership and supervision of the bridge watch team

executing the ship’s daily routine (POD)

Junior Officer of the Deck and Junior officer of the watch

the principle assistant to the underway OOD

assist in training the Conning Officer and other bridge watchstanders

assist in managing special evolution checklists

conning officer

• The Conning Officer directly controls the engine and rudder angle orders of the ship.

  • Supervise the Helmsman and Lee Helmsman

  • Authorize and supervise the Helmsman, and Lee Helmsman

Boatswains Mate of the Watch

• The BMOW supervises and trains the enlisted members of the bridge watch team.

• Pass words over the ship’s general
  announcing system (1MC)

• Assist the OOD, JOOD, and JOOW
  as directed

quartermaster of the watch

• the QMOW is assigned from Navigation department and serves as the Navigator’s direct representative to assist the OOD, JOOD, and JOOW in navigational matters per the NAVDORM and ship’s Navigation Bill

• provide continous navigation watch on the bridge

Helm Safety Officer

junior officer manned per the COs restricted maneuvering doctrine

supervises and ensures that the helmsman and Lee Helmsman operate the ship safely and in compliance with procedures.

CO’s standing order

• CO expectations and standard operating procedures for your ship while underway, at anchor, or in port

• Specifically address the day-to-day management of the ship’s routines that form the foundation of safe shipboard operations 

  • Define the authorities and responsibilities for all major watch and control stations

  • Define which situations warrant a report or require permission from the CO, XO, NAV, and other shipboard personnel

CO’s night orders

• CO’s Night Orders supplement the CO’s Standing Orders and often discuss the procedures for operating at night, through the following morning

Purpose of Navdorm

• The NAVDORM publishes Type Commander (TYCOM) minimum navigation policies, procedures, and organizational standards for all surface ships. 

NavDorm contains six chapters

• The NAVDORM contains six chapters:

  1. Introduction

  2. Duties and Responsibilities

  3. Standard Policies, Requirements, and Procedures

  4. Supplemental Policies, Requirements, and Procedures

  5. Amphibious Warfare Craft

  6. Records, Logs, and Forms

fix accuracy and maximum fix interval guidelines

What are key watch stations manned during sea and anchor evolutions?

• OOD (Officer of the Deck)

• JOOD (Junior Officer of the Deck)

• CONN

• QMOW (Quartermaster of the Watch)

• CICWO (Combat Information Center Watch Officer)

• Helmsman/Lee Helmsman

• Lookouts

• Safety Observers

• Aft Steering Helmsman

• Piloting Officer

• Surface Watch Officers

• METOC Officer (if assigned)

Q: What is the Navigator’s role in the NAVBRIEF?

• Supervises preparation and delivery of the Navigation Brief

• Signs the final brief along with the XO and CO

• Covers key details such as tides, currents, weather, charts, track, hazards, and special considerations

• Maintains a signed copy of the brief for at least 12 months

what key information does the navigator present in the NAVBRIEF

• Arrival/departure timeline

• Tides and currents (with graphs)

• Weather conditions (visibility, radar ranges, illumination)

• Astronomical data

• Navigation charts and corrections

• Track/course/speed details

• Special considerations (flag visits, VIPs, harbor events)

what is the conning officers role in the NavBrief

• Describes track, courses, and speeds

• Explains maneuvering intentions, including rudder angles, tugs, anchoring, and mooring

• Coordinates with the Navigator and OOD on traffic schemes and pilot arrangements

• Briefs safety precautions during pier approaches and departures

how are hydrographic features symbolized on nautical charts

hydrographic features include soundings, depth contours, underwater obstructions, and bottom types. These are shown using specific symbols and abbreviations found in Chart No. 1. Soundings are typically in fathoms or meters; deeper areas use lighter shades, and shallow/dangerous areas are more prominent.

how are aids to navigation symbolized on nautical charts

Aids to navigation (AtoNs) like buoys, lights, and beacons are represented with symbols in Chart No. 1. Characteristics such as light color, flash pattern, and buoy type are included. Lighted aids use a magenta flare symbol and include details like group flashing (Fl(3)) and period.

how are landmarks symbolized on nautical charts

Landmarks are depicted with symbols and descriptions in Chart No. 1. These include buildings, towers, water tanks, and natural features like cliffs or hills. Significant landmarks used for visual navigation are often marked in bold or with specific shape indicators.

how are areas, limits, tracks, and routes symbolized on nautical charts?

These are indicated using various line styles and colors. For example:

• TSS (Traffic Separation Schemes) use magenta arrows.

• Restricted areas, anchorage zones, and exercise areas are boxed or outlined.

• Routes and tracks are often dashed or solid magenta lines.
  Refer to Chart No. 1 for exact symbology.

what are the main publications used in navigation and voyage planning

• NAVDORM (navigation policies)

• Chart No. 1 (symbols/abbreviations)

• NOAA Coast Pilots (U.S. coastal info)

• Sailing Directions (foreign coast info)

• Light Lists (USCG for U.S., NGA Pubs 110–116 for foreign)

• Pub 151: Distances Between Ports

• Pub 117: Radio Navigational Aids

• Pub 102: International Code of Signals

• World Port Index (Pub 150)

• Nautical Almanac

• Notices to Mariners (NGA/USCG for chart corrections)

what is a movrep and what are its types

A MOVREP (Movement Report) communicates ship position and movement intentions. Types include:

• Departure

• Arrival

• Position

• Cancellation

when is a MOVREP required

• 24–48 hours before getting underway

• Upon arrival

• When deviating more than 4 hours or 50 NM from PIM

• During storm evasion (every 24 hrs)

• When composition or plan changes

what info is in a MOVREP

Track data (lat/long), ETD/ETA, route type (GC, RH, CO, DI), mission details, and rendezvous info.

What are the three main categories of forces that act on a naval vessel?

• Controllable forces: Lines, anchors, tugs, engines, rudders, bow/stern thrusters

• Semi-controllable forces: Shallow water effects, bank cushion/suction, passing ship effects

• Uncontrollable forces: Wind and current

how does a ship’s pivot point change with speed and engine commands

• At rest: Pivot point is at the ship’s center

• Moving ahead: Pivot point moves forward, about 1/3 from the bow

• Increasing ahead bell: Pivot point moves further forward, increasing leverage on the stern

• Astern bell: Pivot point shifts aft, enabling more bow movement
  Rule: The pivot point moves to the point of greatest resistance.

what are the key hydrodynamic effects that impact shiphandling

• Propeller side force: Causes stern to “walk” sideways, especially in single-screw ships

• Rudder effectiveness: Greater when going ahead than astern; requires water flow

• Suction and discharge current: Increases rudder effectiveness as discharge current increases

• Shallow water effects:

  • Squat: Stern/bow sink deeper at high speeds

  • Sinkage: Overall increase in draft

  • Bank effects: Cushion (bow pushed away) and suction (stern pulled in)

• Passing ship effects: Change pressure fields and can cause lateral movement

what is the standard format for issuing commands to the helm and lee helm

• Command: Given by the Conn

• Reply: Helm/Lee Helm repeats verbatim

• Action: Watchstander executes the order

• Report: States when action is complete

• Acknowledgement: Conn says "Very well"

what are the standard rudder angles

• Standard rudder: 15°

• Full rudder: 30°

• Hard rudder: 35°

• Amidships: 0° (rudder centered)

when should steady on course be used

When the ship should hold a specific heading during or after a turn.
Example: “Right standard rudder, steady on course 090.”

what is the purpose of the command → acknowledgement format in shiphandling

To ensure clarity, accountability, and verification between the Conn and watchstanders to avoid confusion during maneuvering.

What are the five parts of a standard command cycle?

1. Command – Conn gives the order

2. Reply – Watchstander repeats it back

3. Action – The order is carried out

4. Report – Completion is reported

5. Acknowledgement – Conn says “Very well”

what are the common rudder commands given to the helm

• Right/Left standard rudder”

• “Right/Left 10 degrees rudder”

• “Hard right/left rudder”

• “Rudder amidships”

• “Steady on course ___”

• “Come right/left, steer course ___”

• “Ease your rudder”

• “Shift your rudder”

• “Meet her”

• “Mind your helm”

what are the common engine commands to the lee helm

• All engines ahead one-third/two-thirds/standard/full/flank”

• “All engines back one-third/two-thirds/full”

• “Indicate pitch and turns for ___ knots”

• “Indicate ___ RPM at ___% pitch” (for controllable pitch ships)

what is the difference between helm and lee helm

• Helm: Controls the rudder (ship's heading)

• Lee Helm: Controls the engines (speed and direction)

what are the bridge watchstander duties during a man overboard (MOB)

• Execute immediate rudder and engine commands

• Announce “Man Overboard” over 1MC

• Hoist Flag Oscar

• Activate pulsating red light and sound six short blasts

• Point to the person in the water

• Deploy life ring and smoke float

• Notify nearby ships via VHF

• Prepare for recovery maneuver

• Use MOBI and radar/SART as applicable

what are the immediate actions after a MOB is reported or observed

• Sound 1MC alarm and hoist flag Oscar

• Drop smoke float and life ring

• Identify wind direction and best course to create a lee

• Decide on appropriate recovery method

• Issue PAN-PAN call on VHF Channel 16

• Initiate recovery maneuver based on situation

what is a PAN-PAN call and when is it used ?

A PAN-PAN call signals urgency concerning the safety of a person or vessel.
Example:
“Pan-Pan, Pan-Pan, Pan-Pan. This is WARSHIP 85, man overboard port side...”

what are the four primary MOB recovery maneuvers

• Anderson Turn – Quickest, used when person’s location is known

• Williamson Turn – Used when MOB location or time is uncertain

• Race Track Turn – Used when towing equipment

• Y-Backing – Used in poor visibility (e.g., submarines)

anderson turn

• Full rudder toward MOB

• All engines ahead full

• Keep MOB in sight

• Quickest recovery, but requires immediate detection

williamson turn

• Full rudder toward MOB, then full opposite after 60° deviation

• Steer reciprocal of original course

• Good for unknown time/location of MOB, but slower

Race Track Turn

• Two full turns in opposite directions

• Keeps a steady path over water and allows recovery from lee side

• Best when ship is towing or streaming gear

Y-Backing maneuver

• All engines back full, rudder full toward MOB

• When stopped, shift rudder and engines ahead

• Allows low-visibility ships to reverse then re-approach MOB

what is the Wind/Ship/Man concept

the ship should be positioned between the wind and the man, so wind blows the ship toward the MOB

what is a catenary in towing operations

A catenary is the natural curve formed by a hanging towline under its own weight. It acts like a spring, absorbing shock and sudden movements in the tow.

what does “In Step” mean in towing

"In Step" means both vessels crest and trough waves at the same time, minimizing strain on the towline. It’s achieved by adjusting the towline length.

what are key pieces of towing equipment

• Towing Hawser (synthetic or wire)

• Towing Thimble

• Messenger line

• Pelican Hook Assembly

• Chafing Chain

• Towing Chain Stopper

• Padeyes (vertical/horizontal)

• Bullnose & Stern Chock

• Turnbuckle

where can you find towing rigging info for your ship

In the Ship’s Information Book (SIB) — contains the towing drawing specific to the vessel.

What are the four standard towing approach methods?

• 45° Approach – Used in moderate winds or seas

• Backdown – Used in light and variable winds

• Parallel – Used in moderate conditions, about ⅓ of the towline's length apart

• Crossing the T – Used in heavy seas/winds, with approach perpendicular to the towed vessel

what are proper steps for getting underway while towing

• Bring engines ahead slowly

• Stop when hawser takes strain

• Continue slowly ahead until inertia of the towed ship is overcome

• Maintain steady tension

how should a towing vessel change course or speed

Gradually — to avoid placing excessive strain on the towline.

what should a towing vessel do if it loses propulsion

change course and speed immediately

prevent collision with the vessel being towed

what is the basic principle of the magnetic compass

it uses magnetized needles aligned with Earth’s magnetic field to point toward magnetic north

what are the 3 types of magnetism that affect a compass

terrestrial (variation)

induced( from earths field acting on the ship)
permanent (from construction/ repair vibrations)

what are the standard compass notations

• T = True

• M = Magnetic

• PSC or C = Standard/Per Steering Compass

• PGC = Per Gyro Compass

• Example: 090°T, 087°M, 085°PSC

what is a digital flux gate magnetic compass

an electronic magnetic compass located at the helm that sense the earths magnetic field using fluxgate sensors

How often must a DFGMC be calibrated?

• Within 24 hours of any special evolution (e.g., anchoring, UNREP)

• Within 48 hours of getting underway (per NAVDORM)

What is variation?

The angular difference between true north and magnetic north, due to the Earth’s shifting magnetic field.

How is variation found?

On the compass rose closest to the ship’s DR position on the chart.

what is deviation

The error caused by magnetic influences within the ship, causing the compass to deflect from magnetic north.

How is deviation reduced on Navy ships?

Through deperming, which uses high electrical currents to erase induced magnetism.

What is compass error?

The total angular difference between true heading and compass heading, combining variation and deviation.

What’s the mnemonic to solve for compass error?

Can Dead Men Vote Twice @ Elections
C = Compass
D = Deviation
M = Magnetic
V = Variation
T = True
Add East, Subtract West

How do you determine the magnetic course to steer?

True - Variation = Magnetic, then account for deviation to get the compass course.

How does a gyrocompass work?

It uses a spinning wheel (gyroscope) aligned to true north by compensating for Earth’s rotation through controlled precession.

What are the 3 axes of a gyrocompass?

• Spin axis

• Horizontal axis

• Vertical axis

What systems use gyrocompass input?

• Steering repeater

• Autopilot

• Radar

• Electronic navigation systems

• Course recorders

What should be done if the gyrocompass fails?

• Use relative bearings and convert to true by adding ship’s heading

• Switch to backup gyro

• Use visual ranges or celestial fixes

What causes gyrocompass error?

• Friction

• Ship’s motion (latitude/speed)

• Electronic malfunction

• Power fluctuation

How is gyro error checked?

• Visual ranges

• Azimuth/amplitude of celestial bodies

• Comparison with known true bearings

• Pier heading when moored

How do you calculate gyro error?

Compare the Gyro (PGC) reading with a known true bearing.
Use the mnemonic:
Gyro Least, Error East
Gyro Best, Error West

what is an aid to navigation

any fixed or floating device used to assist a mariner in navigation by warning of dangers, marking safe water, or indicating a safe course. includes beacons, buoys, lights, fog signals and ranges

What are the primary purposes of AtoNs?

• Indicate position

• Mark channels and hazards

• Provide direction

• Warn of dangers

• Assist in fixing position

How do AtoNs communicate information to mariners?

Through color, shape, light characteristics, topmarks, and sound signals.

What is a beacon?

A stationary NAVAID. Lighted beacons are lights, and unlighted ones are daybeacons with dayboards or structural daymarks.

What is a buoy?

A floating AtoN used where fixed structures are impractical. May be lighted, have sound signals, and are secured by a mooring chain (defining a watch circle).

what are fog signals

Audible signals (bells, horns, gongs, whistles) used in low visibility. They can be deceptive due to refraction or wind.

What is a visual range (range lights)?

Pairs of NAVAIDs that form a line of position when visually aligned. Used to stay centered in channels.

Which publications describe light characteristics?

• Light Lists (USCG, Vol. 1–7)

• List of Lights (NGA Pubs 110–116)

• Chart No. 1

What do light characteristics describe?

• Color (white, red, green, yellow)

• Phase (Flashing, Occulting, Isophase)

• Period (duration of full light cycle)

What is a buoy’s watch circle?

The circular area within which a buoy moves, defined by the length of its mooring chain. Largest at MLLW (low tide).

What are the five main types of marks?

• Lateral Marks – define channel sides

• Isolated Danger Marks – mark hazards (black with red bands, 2 black balls)

• Safe Water Marks – red/white stripes, mark centerline or landfall

• Special Marks – yellow, indicate special areas

• Information/Regulatory Marks – white/orange, show danger, exclusion, restriction, or info

What does the color and number of a lateral buoy mean in IALA Region B (U.S.)?

• Red = starboard when returning from sea (even numbers)

• Green = port when returning from sea (odd numbers)

What are common buoy shapes and topmarks?

• Shapes: Can, Nun (cone), Pillar, Sphere, Spar

• Topmarks: Help distinguish marks (e.g., red ball for safe water, black spheres for danger)

What are the two major buoyage systems?

• Lateral System: Best for channels

• Cardinal System: Best for open sea and isolated hazards

Which IALA Region is the U.S. in?

IALA Region B

• Red buoys = starboard side when returning from sea

• Green buoys = port side when returning from sea

What are two types of electronic AtoNs?

• RACON (Radar Beacon): Responds to radar, gives range and bearing

• RAMARK (Radar Marker): Continuously transmits a signal, gives bearing only

What is a VAtoN?

A Virtual Aid to Navigation displayed only on AIS/ECDIS systems. Used to mark subsea hazards, pipelines, or no-go zones.

What is a fix?

A fix is a position determined without reference to any former position, found by the intersection of 3 or more lines of position (LOPs).

What is dead reckoning (DR)?

DR is estimating the ship’s future or past position based on course, speed, and time from a known position.

What is a line of position (LOP)?

A single line along which the ship lies, based on a bearing or range to a navigation aid.

How is course and speed labeled on a chart?

• Course: Above the line, in 3-digit format, labeled "T" for true or "M" for magnetic

• Speed: Below the line, in knots (e.g., "10 kts")

What are the six rules of DR?

1. Every hour on the hour

2. Every course change

3. Every speed change

4. When obtaining a fix or running fix

5. When obtaining a single LOP

6. Plot and label new course, speed, time, and DR at least two fix intervals ahead

What tools are used for navigation plotting?

• Dividers: measure distance

• Plotters: plot courses (PMP, Rolling Ruler, Parallel Ruler, Triangles)

• Compasses: plot range arcs

• Compass Rose: determine true/magnetic bearings

What do you need to plot a DR track?

• Starting fix

• Course

• Speed

• Time interval
  Then use these to project position forward (and label accordingly)

What can cause DR errors?

• Inaccurate course/speed inputs

• Set and drift from current or wind

• Human plotting error

• Failure to update DR at required intervals