Si-tex SNS-1100, User Manual

Page: 90 / 114

90
- User Manual
value expressed in the current depth unit.
• STR = Steering
Difference between COG and CTS. If COG is 25° and CTS is 30°, then STR is 5° Right.
• STW = Speed Through Water
Speed of the vessel relative to the water.
• TD = Time Difference
Loran positions are determined by precise timing of the intervals between reception of pulses
transmitted by pairs of stations in the selected chain. Between any two stations a ship must be
located somewhere along a line of possible positions where the measured Time Difference,
TD, between arrival of pulses from those stations would be observed. The TD is measured
from the time of reception of the master station signal to the time of reception of the slave
station signal (see also Pair).
• Tide
Periodic rise and fall of the surface of oceans, bays, etc., due principally to the gravitational
interactions between the Moon and Earth.
• Tide Info
Calculates the tide heights for any past or future date and as a by-product of this calculation
will also display the Maximum and Minimum Tide height and time for the day selected plus
the times of Sunrise and Sunset. At some chart levels, the chart plotter will display a new Tide
Diamond Symbol for every Port or tide point in the database covered by that particular DATA
MEDIA.
• Tracks & Routes
Recommended and established routes for ships at sea, including traffic separation schemes,
deep water routes.
• TRN = Turning
Difference between COG and BRG. If COG is 80° and BRG is 75°, TRN is 5° Left.
• TTG = Time To Go
Estimated time needed to reach your destination, based on your current speed and the
distance to destination.
• TWD = True Wind Direction
Direction of the Wind relative to a fixed point on the earth.
• TWS = True Wind Speed
Velocity of the Wind relative to a fixed point on the earth.
• Underwater Objects
Objects like obstruction, wreck, cable…
• User Point
Object you place on the chart identified by its coordinates and displayed on the screen with a
reference symbol (see Mark, Waypoint).
• UTC = Universal Time Coordinated
Time scale based on the rotation of the earth that is used by most broadcast time services.
• UTM = Universal Transverse Mercator
Metric Grid system used on most large and intermediate scale land topographic charts and
maps.
• Variation
Angle between the magnetic and geographic meridians at any place, expressed in degrees
West or East to indicate the direction of magnetic North from true North. It changes from point
to point, and (at the same point) with time.
• VMG= Velocity Made Good
Destination closing Velocity. The VMG is calculated using the current speed of the vessel
(SOG) and the difference between the current vessel course and the bearing to the
destination.