Navigation II (NN204) Final Exam Review

76 Questions – 200 Pts – 25% of Your Grade

Not on the test: Running Fixes; SAPPS; CAPN; STELLA; Computer stuff; Visibility of Lights

Basic: 1deg = 60NM; 15deg arc = 1hr; G+E=T; TVMDCAW (True +- Variation = Magnetic … M +- Deviation = Compass … Add W)

Rules of the Road (10-12 Q’s)

1. The rules apply to all vessels in the great lakes and inland US waters
2. Deviate from the rules rather than get in an accident
3. Definitions of vessels (sailboat is … etc)
5. All ships will maintain a proper lookout
6. Safe speed – maintain a speed such that you can avoid collision and stop in a reasonable distance
7. Risk of Collision – assume you will collide if you aren’t sure; don’t make assumptions on scanty radar information
8. Action to Avoid Collision – alteration of course and speed must be significant and easily noticeable to the other ship
9. Narrow Channels – stay close to the starboard side; don’t impede less maneuverable ships
10. Traffic Separation – cross at right angles, enter at small angle if entering in the middle of the lane
11. Overtaking, meeting, and crossing rules only apply to ships in visual contact
12. Sailing Vessels – a) if wind on different side, then port has right of way; b) if wind on same side, leeward vessel has right of way
13. Overtaking vessels may not impede the other vessel; overtaking if more than 22.5deg abaft the beam
14. Head-on situation – two vessels on near reciprocal courses; alter course to stbd and pass port to port
15. Crossing situation – vessel to starboard has right of way
16. Give-way vessel – take early and substantial action
17. Stand-on vessel – maintain course and speed; maneuver to avoid collision if the other vessel fails to do so
18. Pecking Order – NUC, RIAM, [Constrained by Draft – inland only], Fishing, Sailing, Power, Sea-plane
19. Restricted Visibility – slow to a safe speed; slow to bare steerageway if unsure of where other vessels are
20. Lights and Shapes – follow at all times; do not display anything which could be confused for a light/shape that isn’t one
21. Arc of Visibility – stbd/port lights have 112.5deg arc; stern has 135deg (total 360deg)
22. Visibility of Lights – distances lights must be visible at; 5 lights per 4 ship length types = 20 #s … most ships are 2NM; >50m ships are 3NM

23. – 31. Underway Lighting and Dayshapes – see pictures below

32. Short Blast – 1sec; Long Blast – 4 to 6 sec
33. Req. based on size: >12m – bell and whistle; >100m – gong too
34. Maneuvering and Warning Signals (flashing lights may be substituted for sound)

Meeting or Crossing Situation (short blasts)

1 = leave you port; 2= leave you stbd; 3 = using astern eng. 5=don’t understand

Overtaking Situation 1 = overtake stbd; 2 = overtake port

General 1 = approaching a bend or leaving dock; echo signals to agree

35. Restricted Visibility Situation

1L/2min = underway … 2L/2min = underway, not making way … 1L,2S/2min = NUC, RIAM, anchored, sailing, etc.

1L,3S = last vessel in tow … 2L,1S = overtake stbd (intl) … 2L,2S = overtake port (intl) … 4S = pilot ship

At Anchor: 5sec Bell / 1min = vessels <100m … add 5sec gong if >100m … aground = prev + 3 distinct bell rings b/w bell and gong

36. Signal wildly to indicate distress
37. Distress Signals – Red Star Shells, Dye marker, Radio telegraph, Fog horn sounding, SOS (…---…),R/T, Flames on vessel, radio Mayday, square flag and ball, parachute red flare, wave arms over head, smoke, gun fired at 1min intervals, etc.

Celestial Theory (10-12 Q’s) – excludes SR/SS (includes Celestial Navigation Map) (see HW14)

Celestial Sphere Elements (PPT14)

• Celestial Sphere – infinite radius with its center on Earth; has a North and South Celestial Pole and Celestial Equator (in line with Earth’s)
• Hour Circle – great circles going through the poles of the celestial sphere
• Celestial Meridian – great circles through the poles and zenith
• Declination – degrees above or below the celestial equator (0 is on it, 90 is upwards from the pole…)
• Parallel of Declination – circle parallel to the celestial equator; path on which a star appears to move as the Earth rotates
• Identifying a point on the celestial sphere – requires declination and an hour angle
• Hour angles are from 0 to 360° and referenced from one of three types:
• Sidereal Hour Angle (SHA) - angle west of vernal equinox (Aries) à where sun’s path intersects the celestial equator
• Greenwich Hour Angle (GHA) – angle west of Greenwich celestial meridian
• Local Hour Angle (LHA) angle west of the observer’s celestial meridian
• Which references are used by different bodies: SHA: stars GHA: sun, moon, planets, and Aries

Motion

• Earth rotates clockwise which makes the celestial sphere appear to move slowly counter-clockwise (diurnal motion)
• GHA_star = GHA_Aries + SHA_Star; LHA_star = LHA_Aries + SHA_Star; GHA_star = LHA_star + longitude

Elements of the Horizon Coordinate System

• Zenith – position directly above the observer
• Nadir – directly below the observer
• Observer’s Horizon – perpendicular to zenith-nadir line / axis
• Celest. Horizon – parallel to observer’s horizon but passes through center of the Earth
• Altitude – star’s angle above the horizon
• Sextant Altitude (Hs) – altitude measured by a sextant
• Corrected Sextant Altitude (Hc) – Hs corrected for height of eye
• Observed Altitude (Ho) – altitude after further corrections made to Hc
• Ver. Circle – great circle that through zenith and nadir; perp. to the cel. horiz.
• Principal Vertical Circle – v. circle passing through the N and S celest. poles
• Zenith – angle from the direction of the north pole to the angle where the altitude is measured (angle from the principle vertical circle to the vertical circle on which the star lies)
• Geographic Position – point on earth over which a star is located (found by drawing a line from the star to the center of the Earth)
• Celestial Triangles
• Three points: (North) Celestial Pole, Celestial Body, Observer’s Zenith
• Three sides:
• Co-altitude – from zenith to celestial body = 90° - altitude
• Co-latitude – from zenith to celestial pole = 90° – latitude
• Polar Dist. – angular dist. from celest body to celest pole = 90° +/- codeclin.
• Add 90 if the celestial body and pole are in different hemispheres; subtract if in the same hemisphere
• Three inner angles (two important ones):
• Meridian angle (-t-) – at celestial pole; related to LHA
• Azimuth Angle (-Z-) – at zenith
• Note: Given latitude, declination, and a meridian angle, you may solve for altitude and azimuth angle
• Co-altitude – angle between your position and a star’s GP; angle from the vertical; = 90 - Ho
• Circle of Equal Altitudes – a set of points on a circle centered on the star’s GP on which the altitude appears the same for the star
• Radius is the co-altitude … 1min arc = 1nm so if co-alt. is 40 then your distance from GP is 40*60’/deg * 1°/nm = 2400nm
• Highlighted celestial navigation points
• Cancer and Capricorn Importance – they mark the maximum declination of the sun
• True azimuth is the true bearing to the star
• When the sun’s LHA is 0deg, LAN (local area noon) is occurring and thus it is at its highest point
• Gyro Error by Polaris – usable in the northern hemisphere between the equator and 65° latitude
• Latitude by Local Apparent Noon
• 1^st Case: Latitude = Declination + 90° – Altitude à sun in the same hemisphere; sun latitude < your latitude
• 2^nd Case: Latitude = Declination – (90° - Altitude) à sun in the same hemisphere; sun latitude > your latitude
• 3^rd Case: Latitude = 90° – Altitude - Declination à sun in a different hemisphere
• Latitude by Polaris doesn’t work in the southern hemisphere

Moboards – stationing, contact tracking, true wind, desired wind (one of each on the test)

• No examples right now; I’ll try to get some out later L

Bridge Clearance Problem: Vertical Clearance = Charted Clearance + Mean Tide Level + ½ * Mean Range – Tide Level

• MTL and MR in table 2 in the book; Tide Level given (normally from CAPN)

Tides Caused by the sun, moon, and rotation of the Earth (coriolis effect – natural circulation of water due to rotation of Earth)

The Two Types of Currents are Global and tidal

Navigation Team Members -- Navigator, 1JS and JL phone talker, Radar operator, Fathometer operator, Bearing taker, Plotter, Surface tracker, Shipping Officer, Piloting Officer

Six Rules of DR -- Every: hour on the hour, speed change, course change, fix, LOP; DR two times for each fix interval

Anchoring Procedures

o Considerations: sufficient navaids, safe seas, bottom characteristics, depth, proximity to others

o Approach Track – final leg that ship drives to get to anchorage

o Head Bearing – bearing to navaid which is same as the approach track

o Letting-go Circle – circle around anchorage; radius = distance (D) from hawsepipe (where anchor lets out) to pylorus (pilot house)

o Letting-go Bearing – anchor drop point

o Range Arcs – 100yd increments from Letting-go bearing to 1k and then at 1.2k, 1.5k, 2k yards

o Swing Circle – circle around anchorage; radius = chain length + ship length

o Drag Circle – circle around anchorage; radius = D; if outside this circle, then you’re dragging the anchor

o Post-Anchor Considerations: have anchor watch, pick navaids to use at anchor, put acetate on swing/drag circles

Time and Distance Problem

• Ex: Find time you will arrive in Japan (their time) if you leave at XXXX (our time)
• 1) Find how long it takes to get to Japan and add that to XXXX
• 2) Convert the time you arrive in Japan (our time) to their time

Info in the Pubs

• PUB #1-N / Catalog of Nautical Charts / Catalog of Hydrographic Products – list of all unclassified charts and pubs
• US Coast Pilot – info on US harbors and coast
• Sailing Directions – info on harbors and coastal areas not in the US
• Fleet Guide – info on US Naval bases
• Light List – US light information
• List of Lights – International light information
• Pub 151 – Distances between ports
• Pilot Charts – conditions in an area in a given month

Time Conversion (to Zulu and lat and long to a zone)

• From S to F would be -12 … from Z to T = +7 … from Z to F = -6

Message Types

• OTSR – optimum track ship routing – signal with new, safer, alternate track (in case of severe weather)
• WEAX – daily weather forecast for the next 72hrs; only includes your PIM (plan of intended movement) area
• MOVREP – Movement Report – where the ship is headed; must stay within four hours of this
• LOGREQ – before entering/leaving port; indicates what services are needed

Air mass descriptions and interactions, where they come from, stability

• Air Masses – large air body with similar properties at a given height
• Types
• 1) Low Pressure – cyclonic, surface convergence (upward vertical motion)
• 2) High Pressure – anti-cyclonic, surface divergence
• Classifications by Temperature and Humidity Properties
• Humidity c = continental (over land :: dry) m = maritime (over water :: moist)
• Temperature P = polar (cold) T = tropical (hot)
• Combinations of these are classifications: cP, etc.
• Others cA = c Artic = dry, extremely cold mE = m Equatorial = moist, extremely hot
• Modifications to Air Masses as they move (stability)
• Warm over cold is stable à little vertical mixing (warm air is less dense so it rises)
• Dry air more dense and more stable
• Fronts
• Fast-moving fronts – 1:50 (vertical rise to horizontal distance; km) … Steep slope pushes front alongside or ahead of the front
• Slow-moving fronts – gentler slope (1:150, etc) … Has cloud cover behind the front (slide #22)
• Frontolysis – temperature contrast lessens causing the front to break up
• Frontogenesis – temperature contrast increases, strengthening the front
• Occluded Front – combination of a warm and cold front; severe weather
• Cold Occlusion – colder air in the back … Warm Occlusion – air is slightly warmer in the back (cold front, cool back)
• Triple Point – warm, cold, and occluded front all touching; most severe weather
• Front occurs where there are changes in: 1) Temperature; 2) Dew point; 3) Wind direction; 4) Pressure; 5) Clouds

Synoptic Reports

• Every 6 hours: PRIORITY à wind < 33kts, seas <12ft
• Every 3 hours: IMMEDIATE à wind > 33kts, seas >12ft (sustained)
• Plain voice if cyclone, etc. sighted

Behavior of storms in the Northern Hemisphere -- Spin counter-clockwise

Types of Storms and Speeds

• Closed cyclonic – rotating storms
• Tornado – violent rotating storm, small diameter, over land, >150mph
• Waterspout – tornado over water (less destructive)
• Squall – intense wind due to atmospheric instability; comes and goes quickly; sometimes accompanied by precipitation
• Monsoon – steady winds with frequent squalls and thunderstorms
• Tropical Storms: 1) Hurricane > 63kts; 2) Tropical Storm 34 to 63kts; 3) Tropical Depression < 34 knots
• Noncyclonic – produced by prevailing winds; predictable – Gale: 34-47mph … Storm: >48mph

Twilight Types

• Civil Twilight – when the sun’s center is 6° from the horizon
• Clear horizon; 1^st and 2^nd magnitude stars visible
• Nautical Twilight – when the sun’s center is 12° from the horizon until Civil Twilight
• First chance to shoot a celestial fix

Lights vocabulary (luminous range, nominal range, period, phase)

• Luminous Range – distance a light can be seen based on meteological visibility
• Nominal Range – distance a light can be seen in clear visibility
• Phase – fixed; occulting = long flash; isophase = equal on/off; flashing; quick flashing; alternating = multi. colors
• Period – length of time for a light to progress through a complete cycle

Definitions of radar components and flow charts

• Transmitter: produce radio waves
• Modulator: produce pulses
• Antenna: transmit pulses and receive echoes
• Receiver: amplify weak echoes and demodulate them
• Repeater: display the info

New GPS works and its features and who makes GS08NA88 and Galileo

• 24 satellites + 4 spares; run by MCS (master control station) and 5 monitor stations; 3 fixes = 2D; 4 fixes = 3D
• 4 Advantages – accurate, 24hr, passive, all-weather system
• 3 Components – space, control, and user segments
• Figure of Merit (FOM) – 1-9; 1 is the highest
• Selective Availability – Pres can turn it off; P-code is encryption which makes it more accurate for the military
• DGPS – ground signal broadcasted which corrects GPS; only available on US coast and up the Mississippi (used by USCG)
• GLONASS – 8 satellites; Soviet satellites; SGS-85 datum
• Galileo – EU project planned for 2008; 30 satellites; user fee planned; P-code accuracy and better

Projection Chart Types: Mercator – rhumb lines as straight lines … Gnomic – great circles are straight lines

WGS-84: most commonly used datum; World Geodetic System 1984 (ECDIS based on it)

Navy also uses NAD – North American Datum 27 – based on ellipsoids

Digital Charts: Raster – scanned paper chart … Vector – digitized chart; scalable; more expensive to create

• ECS – Electronic Chart System (not legal for sole use)
• ECDIS – Elec. Chart and Database Info. System (real-time planning, reduce manning, improved safety and awareness)
• ECDIS-N – navy standard ECDIS; reads NGA and DNC charts
• NAVSSI – Navigation Sensor System Interface – provides precise, quick information to nav, C4I, combat sys., etc.
• NAVSSI-Lite – low-cost variant used by the USCG
• VMS – Voyage Management System – voyage planning, radar overlay, automatic navigation, data recorder, future estimator

Universal Transverse Mercator CS: divides world into zones 8deg lat by 6deg long; numbered 1-60 W to E and c-x S to N

Military Grid Coordinate System (MGCS)

• 24751610 EastNorth Starting Point (24, 16) From there, go 75m East, 100m North

Written by David Underhill based on the questions asked in the review by LT <currently unknown>

Other Stuff:

Station Guide

38 = temp, 12 = dewpt; black = % clouds

short line = 5kt; line = 10kt; Δ= 50kts

direction of line off the circle = wind dir

51 = 1005.1mB … if it was 9 then 1009mB

little dots = snow