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NAVIGATION TRAINING

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Title: NAVIGATION TRAINING


1
NAVIGATION TRAINING Section 10 Currents and Waves
2
Table of Contents
  • Section 1 Types of Navigation
  • Section 2 Terrestial Coordinates
  • Section 3 Charts
  • Section 4 Compass
  • Section 5 Nautical Publications
  • Section 6 Navigational Aids

3
Table of Contents
  • Section 7 Buoyage
  • Section 8 Position Lines and Fixes
  • Section 9 Tides
  • Section 10 Currents
  • Section 11 Weather

4
Ocean Currents
5
Ocean Currents
  • Giant patterns of rotation gyres in each of the
    major ocean basins.
  • Caused by natural effects salinity, temperature,
    the Coriolis Effect, etc.
  • Described in the Sailing Directions
  • Examples are the Gulf Stream, the Kuro Shio and
    the Owa Shio

6
Ocean Currents
7
Ocean Currents
8
Tidal Currents
9
Tidal Currents
10
Tidal Currents
  • Caused by the rise and fall of tides in coastal
    waters.
  • Speed and timing is dependent upon whether it is
    spring or neap tides, and the shape of the coast
    and the sea floor.

11
Tidal Currents
12
Relationship of Terms
  • Flood Current
  • A tidal current that flows towards shore (follows
    a low tide).

13
Relationship of Terms
  • Ebb Current
  • A tidal current that flows away from shore
    (follows a high tide).

14
Relationship of Terms
  • Slack Water
  • A period where there is no horizontal movement of
    water. Corresponds to the stand of the tide.

15
Set and Drift
  • Set the direction of the current pushing
    normally expressed in oT.
  • Drift the speed of the water, normally
    expressed in knots.
  • Set and drift combined describe the current.

16
Waves
17
Waves
  • If the wind is blowing from the water onto the
    land they are onshore winds. This causes waves to
    break a little earlier, thus pushing them over.

18
Waves
  • If the wind blows from the land out to sea, they
    are offshore winds. They blow against the
    incoming swell and sustain the waves from
    breaking while they jack up a little higher and
    steeper before they break.

19
Water Temperature
  • Water temperatures off Vancouver Island vary
    between the high 40s F in the winter and the low
    70's in the height of the summer, whilst
    temperatures in the inland waters can be a little
    cooler, some only getting up to only 55F.

20
Swell
21
Swell
  • Most of the swells on the British Columbia coast
    are generated by storms that start in the
    Aleutians and spin down the coast of North
    America all fall and winter.
  • They get dragged onto the continent by the jet
    stream anywhere from Alaska to California.

22
Swell
23
Swell
  • This forces the water up and sort of trips the
    wave and it breaks, the top of the wave falls
    down in front of itself.
  • Here in BC the storms fire swell at us over a
    shorter distance. As a result, because our
    beaches slope gradually, our surfing waves are
    comparatively scaled down in size and power.

24
Rip Currents
25
Rip Currents
  • A Rip Current is a current of water flowing out
    to sea.
  • Rips form when waves push large volumes of water
    onto the shore and the water returns seaward
    thorough channels between sand bars, behind
    islands and around rocky headlands.

26
Rip Currents
  • On a sea coast, they can be identified by a line
    of discoloured water, foam and debris floating
    seaward or an area on choppy or confused water in
    the swell.

27
Rip Currents
28
Local Knowledge
  • In all outings on the water, observe local
    currents and waves, what direction they flow at
    what times, where the areas.
  • This will assist in
  • 1. Plotting the best course in certain weathers.
  • 2. Knowing where floating objects might end up
    going ashore under the effects of the current.
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