Page 221 - NAVAL SCIENCE 3 TEXTBOOK

lW LE S O~ T ilE HOAD A N D ,\IA N EUV EIU N G BOARD 227

the reciproctll (opposite) of the bearing of vector ell' is read lIsing 7. Your own ship is on course 090°, speed 10 knots. You sight
the Sllltll\ numbers inside the perimeter of the maneuvering board. ,1 ship 1\-1011 course 270°, speed 15 knots. \Vhat are the
To solve for reltltive wind given the ship's course clild speed and magnitudes and directions of the following vectors:
true wind, a reverse procedure to that described above is folJowed. A. The er vector
First, the ship's and true wind vectors are plotted. The resulting
13. The elll vector
vector nv then defines the relative wind. Its direction is specified
C. The rill vector
relative to vector cr, and its velocity is obtained by measuring its
8. Your own ship is on course 025°, speed 12 knots. You sight
length along the speed scale beillg used for the problem.
a ship 1H on course 000°, speed 15 knots. \Vhat are the
magnitudes and directions of the following vectors?
A. The er vector
STUDY GU IDE QUESTIONS B. The elll vector

I. \·Vhat is the maneuvering board lIsed for? C. The 1"11/ vector
2. At se .. 1, what is the reference for what other vessels and the 9. Your own ship is on course 122°, speed 15 knots. At 0400 a
wind are doing rei<ttive to your vessel? target ship, Sktlllk M, bears 144°,27,000 yards. SkI/ilk M's
course is 020°,;10 knots. \·Vhat will be the bearing and range of
3. A. \Vhat is normally placed at the center of ,1 maneuvering
Skllllk M at CPA?
board, and hoI\' is it labeled'
10. Your own ship is on course 285°, speed 18 knots. At 0800 a
B. \Vhat does vector er represent on a maneuvering bOdrd?
target ship AJ bears 310°, 9,000 yards. Ship All's course is 2 J 5°,
4. What does the relative motion lille (RML) in a CPA-type speed 15 knots. \Vhat will be the bearing and r<mge of.M at
problem indicate? CPA?
5. A t<1l'get ship A'I is tracked 0 11 your ship's ntdar with the II. You are aboard a boat heading 060°, speed 25 knots. Your
following results: anemometer indicates the relative wind to be from 330 R at
0
35 knots. What ,1re the direction and speed of the true wind?
tit/Ie bcarillg mllge (yd,)
12. You are all a boat heading 350°, speed 15 knots. The true wind
0908 276° 10,000
is 10 knots from 240°. \·Vhat are the direction and speed of the
0911 269° 8,300
relative wind?
0914 258° 6,800
0917 244° 5,800
CRIT ICAL THINKING
A. \Vhat is ship All's speed of relative movement?
1. Compare and contrast a maneuvering board solution tor
B. \Vhat are the bearing and range of the CPA?
the course ,1I1d speed of a maneuvering vessel with the
6. Your OWll ship is on course 150°, speed 15 knots. Ship k! is con\'entional head-to-tail graphic solution for the slim of two
observed ,1S lollows: vectors.
time bearing I"IlIIge (yds)
1100 255° 20,000 VOCABU LARY
1106 260° t 5,700 maneuvering board CPA
111 2 270° 11.200 relatiw motion relative motion line (RJ\·lL)
\'ector anemometer
A. What is the CPA of ship M'
vector diagram true wind
n. \·Vhat is the course and speed of ship 1H?
polar plot relative wind
nomogram three-minute rule
six-minute rule