Navigation Flashcards
Earth movements?
23 hrs 56 mins 4 sec for a full turn
=> + 4 mins to have sun in same bearing
Great circle?
Divides earth in 2 equal parts
<=> small circles don’t
Rhumbline?
= Loxodrome:
Crossing all Meridians at same angle
≠ Orthodrome/Great Circle
Special parallels?
because of earth’s inclination by 23.5 degrees
in North winter: earth closest to sun!
Meridian?
Half a Great Circle from pole to pole
How to correct courses?
Draw a compass diagram
Set
(tip of ijmuiden pilot)
[in degrees]
set angle = 60 * Vcurrent / V ship
[deg]
Determine Deviation
- steam around deviation dolphin and compare compass bearing with true bering: delta is CE, so correct by Variation to get deviatin
- sailing through a leading line
- Azimuth (GZV)
- comparing with GPS course only if no leeway and set
Heeling Error
- is maximal on N/S
- is 0 on E/W
- in-between courses: cos (CC)
- HE P and Stb are opposite (Vorzeichen)
- HE proportional to heeling angle
Books for safe navigation
1.Catalogue of BA Charts (world split in areas A to ..)
2. NtM (P = preliminary = pen | T = temporary = pencil)
3. AP 136: Ocean Passages of the World (4 chapters: AO, PO, IO, sailing vessel routes)
4. AP 100: The Mariner’s Handbook
5. Climate Atlas = Pilot Charts (info for every month)
6. Pilots (76 volumes)
7. ALL: list of LIghts and Fog Signals (divided into sailing areas A-P)
8. ATT: Admiralty Tide Tables
9. Atlas of Tidal Currents
10. Admiralty List of Radio Signals (6 volumes)
11. Nautical Almanac
Distiguishing lights
- colour
- period
- character
ALL
Light Characters
- F Fixed
- Oc Occulting (single/group/composite; longer on than off) = opposite to Fl
- ISO Isophase (equal on and off)
- Fl Flashing (single/group/composite)
- LFl (Long flashing of 2 sec+; but less on than off)
- Q Quick Flashing (60/min)
- VQ (120/min)
- UQ (240/min)
Morse U
. . -
You are running into danger
(from e.g. offshore installations)
Safe Water Buoy
(= landfall buoy)
Slow (character) = safe
(LFl; Iso, Oc)
Direction indicating lines
- Leading Lights: leading line to enter port/fairway
- Lights in line: mark an area, a limit (e.g. fixed mile)
-
Direction lights
3.1 Moire light = Inogon (yellow arrows on board)
3.2 PEL (Port Entry Light): very sharply defined sector light with very narrow sectors
Ranges of Lights
- Nominal Range NR (compare power between different lights and determine LR in actual visibility)
- Luminous Range LR (to find range of light in actual visibilty; to decide whether to even bother about GR)
- Geographical GR (to find distance from light when it dips)
Overview of Light ranges
graphic
Nominal Range
- Def: distance from which light can be seen when visibility = 10 M so you can see the lighthouse at 10 M, but the light at e.g. 24 M or 8 M!
-
Use:
2.1 when start looking for what
2.2 find luminous range - Depends on: bulb strength
- Where to find: Chart, ALL
Luminous Range
- Def: distance from which light can be seen in actual visibility (guess; weather forecast; radar ship/shore)
- Use: whether to start looking for the light (LR has to be ≥ GR)
- Depends on: bulb strength (=NR) and actual visibility
- Where to find: Luminous Range Diagram (enter with arguments = nominal range and actual visibility)
Geographical Range
- Def: distance from which light can be seen in the horizon (= dipping light) as long as LR ≥ GR
-
Use:
determing distance to the light => fix (distance + true bearing)
duck&run -
Depends on: arguments =
3.1 elevation
3.2 height of eye - Where to find: Geographical Range Table at beginning of ALL
Duck&Run
Blink
Distance of horizon
Geographical Range Table
