Rate of Turn in Risavika

Rate of Turn
Technique

Rate of Turn in Risavika

STCW 95

Rate of Turn in Risavika

The perfect ROT

The objectives:
Know how to
estimate the ROT
When to execute the
“wheel over” in order
to follow the planned
track
Control the ROT
according to the
speed
Control the speed for
port entry

A perfect ROT
turn

Rate of Turn in Risavika

The formula:
The circle is: 2r

ROT 360

o

/

2r*60/V =

6

o

*V/ 2r = 3V/ r since 

3,14..

2r

r

V

ROT = ----

r

Time to sail 360

o

:

2r * 60

(to get the answer in minutes)

/

V

(velocity

)

ROT= Velocity/Radius or

V/R

Rate of Turn in Risavika

2r

r

V

ROT = ----

r

Let’s say the decided radius
is 0,3 n.m., and the speed is
8 knots
0,3  1/3 instead of 8/0,3

ROT = 8: 1/3 = 3*8 =
24

o

/min

The ROT at radius;
(0.5) ½ = 2*V
(0.3)

1

/

3

= 3*V

(0.25)¼ = 4*V
and so on

Some
simplifying:
r 0,5 = 1/2
r 0,3  1/3
r 0,25 = 1/4
r 0,2 = 1/5

Rate of Turn in Risavika



How to plan?



Tools?

Rate of Turn in Risavika

357

o

1/

2

n.

m

.

Parallel transfer the
courses

12

6

o

r =

1/2

1/2

n.m.

The question is when to put the
wheel over, and how to perform
the turn?

Pu

t

th

e

di

vi

de

rs

he

re



Map of area

Rate of Turn in Risavika

3

5

7

o

12

6

o

r =

1/2

As a rule of thumb :

Wheel over, 1 ships
length before the
pivot point should
leave the course.

Speed 10 knots,
ROT = 2 * 10 = 20

o

/min

As the speed drops; keep the ROT =
2 * V

Set priority:
1

Use rudder to

obtain decided ROT

within the

time of

sailing one ship

length
2

Adjust ROT

according

to the drop

of speed
a) by adjusting the

rudder-angle, or

b) in order to decrease

the speed faster,

reduce the effect on

the propeller and

adjust ROT with

the rudder



How to

sail?

Position to leave
357

o

Rate of Turn in Risavika

Execute the ROT according to the
plan

Rate of Turn in Risavika

Briefing Completed

Any Questions?