5. DUTTON'S NAUTICAL NAVIGATION Flashcards
reference
dutton’s cha 14
define handling characteristics
the ways a vessel responds to engine and rudder orders
for naval vessels handling characteristics are called ___
tactical characteristics
to obtain tactical data for US Navy Ships
NPW 50-A
define pivot point
the point about who the vessels turns when her rudder is put over.
How do pivot points move?
typically aft when slowing and more aft when backing
Define turning circle.
the path inscribed by the vessel’s longitudinal center of gravity in making a turn of 360 deg
Define advance
the distance gained in the original direction until the vessel steadies on her new course; it is measured from the point at which the rudder is put over
The advance
Define transfer
the distance gained at right angles to the original course, measured from the line repsresenting the original direction to the point of completion of the turn. T
transfer is maximized at 180 degrees
Define tactical diameter.
the distance gained to the right or left of the original course when a turn of 180 degrees has been completed
Define Final Diameter
the distance perpendicular to the original course between tangents drawn at the points where 180 and 360 degrees of the turn have been completed.
Should the ship continue turning indefinitely with the same speed and rudder, she will keep on turning in a circle of this diameter. It will nearly always be less than the tactical diameter.
Define standard tactical diameter
a specific distance chosen to be uniform for naval vessels of a particular type.
Define standard rudder.
the amount of rudder angle necessary to cause the ship to turn in the standard tactical diameter at standard speed
Define Angle of Turn
the arc, measured in degrees through which the ship turn from the original course to the final course
How does speed-length ratio work?
a 300 foot ship at 30 knots has a considerably larger turning circle than at 15 kts.
Define approach track
the track that a vessel must make good in order to arrive at the center o her assigned berth
Letting-go bearing
is a bearing to any convenient landmark from the point of intersection of the letting-go circle and the final approach track. should be near the beam to maximize effectivness
Define letting-go point
intersection of the approach track and the letting-go circle
Define Range circles
distance circles of varying radii plotted from the center of the berth with distances measured from the letting-go circle.
Define letting-go circle
the radius o fetch circle is equal to the horizontal distance form the point of th vessel where than anchor will be let go (the hawsepipe) to the point where th instrument that will be used in taking bearings is located.
So, hawespipe to peolorus
Define swing circle.
a radius equal to the ship’s length plus the horizontal companion of the long o anchor cable to be used is plotted.
Define drag circle.
using the actual anchor position as the center and the horizontal component of the anchor cable length plus the letting-go circle distance as the radius
