MTO
https://jeffwatts.name/moodleYou must have a good idea of the meaning of the symbols used on navigational charts. There are many, and so it is a good idea to have a copy of Chart 5011 handy for reference, especially if you are operating in an unfamiliar area.
The ones listed here are the common dangers, and your knowledge of these will be tested.
| Dangers | |
|---|---|
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Danger line: A danger line draws attention to a danger which would not stand out clearly enough if represented solely by its symbol (e.g. isolated rock) or delimits an area containing numerous dangers, through which it is unsafe to navigate. |
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Rock which does not cover, height above Chart Datum. |
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Rock which covers and uncovers, height above Chart Datum, where known. |
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Rock awash at the level of Chart Datum. |
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Underwater rock over which the depth is unknown, but which is considered dangerous to surface navigation. |
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Danger lines are also used to highlight a danger that is out side its corresponding depth area: Inside the corresponding depth area Outside the corresponding depth area. |
  
Uncovers - Awash - Underwater |
The way to remember the meaning of the dots, crosses and asterisks is to visualise that the amount of lines that make up the symbol represents how much of the rock you will see as the tide falls. The first symbol is highest so you will see more of it. The last symbol is lowest so there is less of it. |
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Anchorage. |
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Wreck of which only the masts are visible at Chart Datum. |
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Wreck showing any part of the hull or superstructure at the level of Chart Datum. |
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Radio reporting point showing directions of vessel movement (2 way and 1 way). |
| Lights | |
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Major light |
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Minor light |
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Beacon with colour, topmark and light
(North cardinal mark) |
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Beacon with colour and topmark unlit
(North cardinal mark) |
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Beacon with colour, topmark and light
(Isolated danger) |
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Beacon with colour and topmark unlit
(Isolated danger) |
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Beacon with colour, topmark and light
(Port hand lateral mark) |
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Beacon with colour and topmark unlit
(Port hand lateral mark) |
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Beacon with colour, no distinctive topmark, unlit |
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Beacon with no distinctive colour or topmark, unlit |
| Tides and currents | |
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Ocean Current - speed and direction fairly constant |
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Flooding Tidal current - speed and direction changes with tides as theyflood(incoming tide - feathered arrow) andebb(out going tide - unfeathered arrow) |
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Ebbing Tidal Current |
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Detailed data over various tidal stages at various locations |
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Eddies |
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Tide rips and overfalls |