5-Change of Station

8/12/2019 5-Change of Station

1/20

Homework Questions

5.3

5.5 5.6

5.8

5.9

5.13


2/20

Change of Station


3/20

Change of Station

R

M1

M2

Guide in center

Our initial position

Our station

assignment


4/20

Change of Station - determineyour required course and speed for a

maneuver

e

mDRM

SRM

Reference shipscourse and speedManeuvering ships

course and speed

rm

er = guideem = your ship


5/20

Change of station problems

utilize both the relative plot andspeed triangle to solve for the

following: Required course and speed to take station

Course to station is given

Stationing speed is given Desired time of arrival at new station is

given

Passing no closer than a specified distance


6/20

Basic Moboard techniques for

Change of Station problems Guide in center

Determine DRM line -between old and new station

Plot er vector and rmvector, solve for em usingvariables given in problems


7/20

Sample Change of Station problem

The guide is on course 050 T, speed 14 kts.

The guide now bears 140 T, range 7,000yds. Take station bearing 211 T, range

7,000 yds from the guide.

FIND: (A) DRM and MRM

(B) CPA bearing and range

(C) Your course to station at 20 kts.

(D) Your course to station at 15 kts.

(E) Your speed if you steer course 120 T

(F) Minimum speed to complete maneuver

(G) Your course at minimum speed


8/20

Find: (A) DRM and MRM Plot our initial position M1 and our

assigned station position M2 Measure the distance between M1 and M2

to find the MRM

Shift the relative movement line from M1 -M2 to the center and read the DRM

Shift the M1-M2 line to the tip of the er

vector and extend the line from the r inthe direction of relative motion

Answer: DRM - 175.5 T, MRM - 11,400 ds


9/20

Find: (B) CPA bearing and range

CPA Bearing = DRM +/- 90 degrees in the

direction of the relative movement line of therelative plot

REMEMBER BEARING IS READ FROM

OWN SHIP TO CONTACT plot line and label point of intersection with

relative movement line M3

CPA range = distance bwtn center of plot to M3

Answer = CPA bearing - 085.5 T, range 4,050 yds


10/20

Find: (C) Your course to station

at 20 kts

You know the length of the em vector is our

ships speed - given

Measure 20 kts on dividers and swing from centerof plot e. Where it crosses rm line indicates

position of m to find the em vector

Read off the course in the direction of e to m

= our course to station Answer = Course -141 T


11/20

Find: (D) Your course to station

at 15 kts

You know the length of the em vector is our

ships speed - given

Measure 15 kts on dividers and swing from centerof plot e. Where it crosses rm line indicates

position of m to find the em vector

Read off the course in the direction of e to m

= our course to station Answer = Course -125 T


12/20

Find: (E) Your speed if you steer

course 120 T

You know our course - direction em vector isdrawn

Draw line from e along course 120. Where it

crosses rm line indicates position of m to findthe em vector

Measure the length of the em vector to give usour speed

Answer = Speed 13.8 kts


13/20

Find: (F) Minimum speed to

complete maneuver

Minimum speed - slowest possible speed atwhich you can complete maneuver

represented as the SHORTEST VALUE

THE em VECTOR CAN BE DRAWN

Draw shortest line from e to the rm vector

Where it crosses rm line indicates position ofm to find the em vector

Measure the length of the em vector to giveus our speed

Answer = Speed = 11.4 kts


14/20

Find: (G) Your course at

minimum speed Read the direction of the em vector to give us

our course

Answer = Course = 085.5 T


15/20

Sample Time problem

The guide is on course 050 T, speed 14 kts.

The guide now bears 140 T, range 7,000yds. Take station bearing 211 T, range

7,000 yds from the guide. CO desires you to

be on station in 20 minutesFIND: (A) Course to station

(B) Speed to station

Fi d (A) C t t ti d (B)


16/20

Find: (A) Course to station and (B)

Speed to station

Plot our initial position M1 and ourassigned station position M2

Measure the distance between M1 and M2

to find the MRM Shift the M1-M2 line to the tip of the er

vector and extend the line from the r in

the direction of relative motion Solve for SRM using required time (20

minutes) and MRM (11,500 yds) - 17.5 kts


17/20

Draw length of rm vector 17.5 kts and

read course and speed to station as em

vector

Answer: Course - 125.5 T, Speed - 15 kts


18/20

Passing no closer than...

10

NM

5NM


19/20

Passing no closer than

Desire to maintain minimum passingdistance between all maneuvering

ships

each CO is different as per COsStanding Orders

3-2-1 rule for maneuvering in

formation with aircraft carriersdo not pass closer than 3,000 yards

ahead, 2,000 yards abeam, or 1,000 yards

astern of a carrier


20/20

Homework

Do Problems 6.2, 6.6, 6.12, 7.2, 7.7,

16.4

Read Chapter 12 (Intercept)

5-Change of Station

Documents

Transcript of 5-Change of Station