EO X51.01 Navigation Theory

EO X51.01 Navigation Theory

Publications, Tides and DST

Note, the hyperlinks are not accessible

Multiple Choice

Canadian Tide and Current Tables is published in how many volumes?

• 1

• 4

• 6

• 5

Multiple Choice

When are NOTMARs published?

• Annually at the beginning of the year

• As required

• Monthly

• Quarterly

Open Ended

What information is included in Sailing Directions

Tide Terminology Canada

•By international agreement chart datum should be low enough that low waters do not fall very far below it

•Regional differences in tidal characteristics lead to different levels of Chart Datum (US vs CAN)

•Lower low water large tide(LLWLT) - Can

Mean lower low water(MLLW) - US

•Depths are measured from lowest water normally observed

•Heights of terrestrial objects are measured from highest water normally observed

• Higher High Water Large Tide(HHWLT) – Canada

 Mean High Water(MHW) - US

Multiple Choice

The vertical rise and fall of a body of water is called......

• Angle

• Flow

• Tide

• Flood

Multiple Choice

A semidiurnal tide has

• 1 low and 1 high tide per hour

• 2 low tides and 2 high tides per day

• 2 low tides and 2 high tides per hour

• 1 low tide and 1 high tide per day

Open Ended

What is the tidal range?

Multiple Choice

An unusually small tidal range is called a

• Neap Tide

• Spring Tide

• Small Tide

• Large Tide

Multiple Choice

An larger than usual tidal range is called a

• Neap Tide

• Large Tide

• Spring Tide

• High Tide

Multiple Choice

LAT is

• Latitude

• Lowest Altimeter

• Something for your coffee

• Lowest Astronomical Tide

Multiple Choice

LAT or Chart Datum is expressed as

• Highest level the tides is expected to fall

• latitude in minutes

• the mid range of tide

• The lowest level the tide is expected to fall

Tide Tables

We will now look at reading and understanding Tide Tables.

Daylight Savings time

•Tide height times are NOT CORRECTED for DST

•For Canada and the USA, if the date you need falls between the 2nd Sunday in March and the 1st Sunday in November, you must correct for DST by ADDING 1 HOUR to the times listed in the table.

Daylight Savings time

Disclaimer: Not every place in the world adjusts their local time for DST. Other nations adjust for DST during different times of the year. Consult the local Sailing Directions and Admiralty list of Radio Signals, Volume 2 to verify.

Tide Table

The next slide shows a Canadian Tide Table

The Reference Port is your location or closest approximate port that the table is created.

The time zone is the local time zone from GMT, there is no DST and you will have to correct

The Month is self explanatory

Tide Values

As described in the preceding videos, this is the values of your high and low tides for the day you have chosen. Using your student work book, complete the exercise questions and find the values on your given tide table. Proceed to the next slide when complete.

Steps for graphing tides

•1. Record the port name and date to be graphed on the tidal graph worksheet.

•2. On the tide table, locate the month and day needed.

•3. Record the time and height of the tide in the corresponding boxes.

Steps for graphing tides

•4. Add one hour to the correction box to convert the time to daylight saving time. Since we are creating a graph for a reference port, there is no correction for the height of the tide, since a graph for a reference point is being created. Enter a zero in the height box.

Steps for graphing tides

•5. Enter the corrected time and height of tide in the boxes. These are the values that will be used to create the tidal graph.

Distance Speed Time

The fundamental navigation calculations involve speed, time and distance. If two of these factors are known,

the third can be calculated by using a formula. To remember the correct formula, a speed-time- distance triangle

(as illustrated in the next slide) can be used. When the needed factor is covered up on the triangle, the correct

formula can be pictured.