DWATCH 2
Who shall take account of the danger posed by fatigue of seafarers, especially
those whose duties involve the safe and secure operations of the ship?
master
The requirements for rest period need not be maintained in case of what?
emergency
For the purpose of preventing alcohol abuse, in any seafarers while performing
designated safety security and marine environmental duties , what is the
maximum allowable limit of alcohol level in the blood as per regulation?
.05%
What is the minimum period of rest of any crew onboard the ship in any 24-hour
period?
10 Hours
What is the minimum period of rest of any crew on board the ship in any 7-day
period?
77 Hours
What are the circumstances wherein the Master may suspend the hours of rest of
the seafarer and what will he ensure to those who have performed work in
scheduled rest period?

The master should suspend the rest hour of the seafarer to perform work
until the normal situation has been restored and to ensure those who have
performed work in schedule with the adequate period of rest.
Quiz 2
Who is bound to ensure that watch keeping arrangements are adequate for
maintaining a safe navigational or cargo watch?
Master
Who is bound to ensure that watch keeping arrangements are adequate to
maintain a safe engineering watch?
Chief Engineer
Who is the master’s representative and is responsible for the safe navigation of
the ship?
Officer in charge of navigational watch
It is a Regulation to be followed for the safe navigation of the ship.
International Regulations for Preventing Collisions
What rule number of COLREG is lookout?
5
How many hours of rest period is given for 77 hours in seven days a week?
The correct answer is: 11 hours
During restricted visibility encountered by the OOW, what action is the least
inappropriate?
The correct answer is: Apply safe speed
What is regulation VIII/I of STCW code?
The correct answer is: Fitness for duty
As OOW, how often will you carry out radar practice?
The correct answer is: Radar practice can be carried out whenever is possible
What does UMS stands for?
The correct answer is:
Unmanned machinery spaces
What is the action of an OOW when risk of collision is detected from a target?
The correct answer is: Take early and positive action at ample time to avoid
collision
What do you mean by adequate compensatory rest period?
Your answer is correct.
The correct answer is: An additional rest period other than normal period of rest
Who shall require that watch schedule be posted where they can be easily accessible?
The correct answer is: Administration
If you’re ask why you are taking compass bearing of an approaching vessel frequently,
what will be your possible answer?
The correct answer is: To early determine risk of collision
When was the Rules of the Intl. Regulations for Preventing Collisions at Sea was
applicable internationally?
The correct answer is: September 1, 1989
What could be the reason the officer in-charge shall not hand over the watch to
the relieving officer?

If the relieving officer is not capable of carrying out the watch keeping
duties effectively
Explain in your own words and in not less than 100 words, the principles under
watch keeping at sea.

The principle of watch keeping at sea is proper arrangements for watch
keeping personnel shall be ensured in accordance with the situations, the
master, chief engineer officer and officer in charge of watch duties shall
maintain a proper watch, making the most effective use of the resources
available, such as information, installations/equipment and other
personnel; Parties shall direct the attention of companies, masters, chief
engineer officers and watch keeping personnel to the following principles,
which shall be observed to ensure that safe watches are maintained at all
times. a proper look out can maintain the safety of the ship and can avoid
collision at sea.
Write down at least three (3) instances wherein the officer in charge of
navigational watch may be the sole lookout.
1. State the weather
2. Weather density
3.Proximity of dangers to Navigation
Give at least 4 reasons relieving officers must satisfy himself before taking over
the watch.
1. Ship estimated or true position and confirm its track
2. Course and speed
3. UMS controls as appropriate
4. Note any dangers to navigation expected to be encountered during the watch
L3 QUIZ 3
When is watch keeping shall be maintained?

Watch keeping is always maintained throughout the watch in any weather
conditions
What rule number of COLREG is the conduct of vessels in restricted visibility
belongs?
Rule 19
Who is in charge for the safety of the ship when there is a pilot onboard?
master
What shall the officer in charge of navigational watch do when in doubt of the
pilots action or intention?

clarification from the pilot and, if doubt still exists, shall notify the master
immediately and take whatever action is necessary before the master
arrives.
What will be the officer in charge of navigational watch do when approaching
ships?

The officer in charge of the navigational watch shall take frequent and
accurate compass bearings of approaching ships as a means of early
detection of risk of collision and shall bear in mind that such risk may
sometimes exist even when an appreciable bearing change is evident,
particularly when approaching a very large ship or a tow or when
approaching a ship at close range. The officer in charge of the navigational
watch shall also take early and positive action in compliance with the
applicable International Regulations for Preventing Collisions at Sea, 1972,
as amended and subsequently check that such action is having the desired
effect.
What are the responsibilities of the officer in charge during restricted visibility?
At least 4 responsibilities
1. Inform the master
2. Post a proper lockout
3. Exhibit navigational lights
4. Operate and use the radar
List 10 duties and responsibilities of the officer in charge of navigation when the
vessel is at anchor.
1.determine and plot the ship’s position on the appropriate chart as soon as
practicable
2.when circumstances permit, check at sufficiently frequent intervals whether the
ship is remaining securely at anchor by taking bearings of fixed navigation marks
or readily identifiable shore objects
3.ensure that proper lookout is maintained
4. ensure that inspection rounds of the ship are made periodically
5.observe meteorological and tidal conditions and the state of the sea
6. notify the master and undertake all necessary measures if the ship drags
anchor
7. ensure that the state of readiness of the main engines and other machinery is
in accordance with the master’s instructions
8. if visibility deteriorates, notify the master
9. ensure that the ship exhibits the appropriate lights and shapes and that
appropriate sound signals are made in accordance with all applicable regulations
10. take measures to protect the environment from pollution by the ship and
comply with applicable pollution regulations
Who is responsible for the safety of navigation?
Master
What does BNWAS stands for?
Bridge navigational watch alarm system
What is SOLAS V/19 all about?

Carriage requirements for shipborne navigational systems and equipment
What method of electronic navigation uses radar to determine position relative to
known objects?
Radar Navigation
DWATCH 2
Who shall take account of the danger posed by fatigue of seafarers, especially
those whose duties involve the safe and secure operations of the ship?
master
The requirements for rest period need not be maintained in case of what?
emergency
For the purpose of preventing alcohol abuse, in any seafarers while performing
designated safety security and marine environmental duties , what is the
maximum allowable limit of alcohol level in the blood as per regulation?
.05%
What is the minimum period of rest of any crew onboard the ship in any 24-hour
period?
10 Hours
What is the minimum period of rest of any crew on board the ship in any 7-day
period?
77 Hours
What are the circumstances wherein the Master may suspend the hours of rest of
the seafarer and what will he ensure to those who have performed work in
scheduled rest period?

The master should suspend the rest hour of the seafarer to perform work
until the normal situation has been restored and to ensure those who have
performed work in schedule with the adequate period of rest.
Quiz 2
Who is bound to ensure that watch keeping arrangements are adequate for
maintaining a safe navigational or cargo watch?
Master
Who is bound to ensure that watch keeping arrangements are adequate to
maintain a safe engineering watch?
Chief Engineer
Who is the master’s representative and is responsible for the safe navigation of
the ship?
Officer in charge of navigational watch
It is a Regulation to be followed for the safe navigation of the ship.
International Regulations for Preventing Collisions
What rule number of COLREG is lookout?
5
What could be the reason the officer in-charge shall not hand over the watch to
the relieving officer?

If the relieving officer is not capable of carrying out the watch keeping
duties effectively
Explain in your own words and in not less than 100 words, the principles under
watch keeping at sea.

The principle of watch keeping at sea is proper arrangements for watch
keeping personnel shall be ensured in accordance with the situations, the
master, chief engineer officer and officer in charge of watch duties shall
maintain a proper watch, making the most effective use of the resources
available, such as information, installations/equipment and other
personnel; Parties shall direct the attention of companies, masters, chief
engineer officers and watch keeping personnel to the following principles,
which shall be observed to ensure that safe watches are maintained at all
times. a proper look out can maintain the safety of the ship and can avoid
collision at sea.
Write down at least three (3) instances wherein the officer in charge of
navigational watch may be the sole lookout.
1. State the weather
2. Weather density
3.Proximity of dangers to Navigation
Give at least 4 reasons relieving officers must satisfy himself before taking over
the watch.
1. Ship estimated or true position and confirm its track
2. Course and speed
3. UMS controls as appropriate
4. Note any dangers to navigation expected to be encountered during the watch
L3 QUIZ 3
When is watch keeping shall be maintained?

Watch keeping is always maintained throughout the watch in any weather
conditions
What rule number of COLREG is the conduct of vessels in restricted visibility
belongs?
Rule 19
Who is in charge for the safety of the ship when there is a pilot onboard?
master
What shall the officer in charge of navigational watch do when in doubt of the
pilots action or intention?

clarification from the pilot and, if doubt still exists, shall notify the master
immediately and take whatever action is necessary before the master
arrives.
What will be the officer in charge of navigational watch do when approaching
ships?

The officer in charge of the navigational watch shall take frequent and
accurate compass bearings of approaching ships as a means of early
detection of risk of collision and shall bear in mind that such risk may
sometimes exist even when an appreciable bearing change is evident,
particularly when approaching a very large ship or a tow or when
approaching a ship at close range. The officer in charge of the navigational
watch shall also take early and positive action in compliance with the
applicable International Regulations for Preventing Collisions at Sea, 1972,
as amended and subsequently check that such action is having the desired
effect.
What are the responsibilities of the officer in charge during restricted visibility?
At least 4 responsibilities
1. Inform the master
2. Post a proper lockout
3. Exhibit navigational lights
4. Operate and use the radar
List 10 duties and responsibilities of the officer in charge of navigation when the
vessel is at anchor.
1.determine and plot the ship’s position on the appropriate chart as soon as
practicable
2.when circumstances permit, check at sufficiently frequent intervals whether the
ship is remaining securely at anchor by taking bearings of fixed navigation marks
or readily identifiable shore objects
3.ensure that proper lookout is maintained
4. ensure that inspection rounds of the ship are made periodically
5.observe meteorological and tidal conditions and the state of the sea
6. notify the master and undertake all necessary measures if the ship drags
anchor
7. ensure that the state of readiness of the main engines and other machinery is
in accordance with the master’s instructions
8. if visibility deteriorates, notify the master
9. ensure that the ship exhibits the appropriate lights and shapes and that
appropriate sound signals are made in accordance with all applicable regulations
10. take measures to protect the environment from pollution by the ship and
comply with applicable pollution regulations
Who is responsible for the safety of navigation?
Master
What does BNWAS stands for?
Bridge navigational watch alarm system
What is SOLAS V/19 all about?

Carriage requirements for shipborne navigational systems and equipment
What method of electronic navigation uses radar to determine position relative to
known objects?
Radar Navigation
Question 1
Incorrect
0.00 points out of 2.00
Question text
When is watch keeping shall be maintained?
Watching keeping is maintained throughout the w atch in any w eather condition the
Answer:
Feedback
The correct answer is: Watch keeping is always maintained throughout the watch
in any weather conditions
Question 2
Correct
1.00 points out of 1.00
Question text
What rule number of COLREG is the conduct of vessels in restricted visibility
belongs?
Rule 19
Answer:
Feedback
The correct answer is: Rule 19
Question 3
Correct
1.00 points out of 1.00
Question text
Who is in charge for the safety of the ship when there is a pilot onboard?
Master
Answer:
Feedback
The correct answer is: master
Question 4
Incorrect
0.00 points out of 2.00
Question text
What shall the officer in charge of navigational watch do when in doubt of the
pilots action or intention?
Seek clarifications from the pilot and if doubt still exist, shall notify the master immed
Answer:
Feedback
The correct answer is: seek clarification from the pilot and, if doubt still exists,
shall notify the master immediately and take whatever action is necessary before
the master arrives.
Question 5
Complete
Points out of 2.00
Question text
What will be the officer in charge of navigational watch do when approaching
ships?
The officer in charge of the navigational watch shall take frequent and accurate
compass bearings of approaching ships as a means of early detection of risk of
collision and shall bear in mind that such risk may sometimes exist even when an
appreciable bearing change is evident, particularly when approaching a very
large ship or a tow or when approaching a ship at close range. The officer in
charge of the navigational watch shall also take early and positive action in
compliance with the applicable International Regulations for Preventing
Collisions at Sea, 1972, as amended and subsequently check that such action is
having the desired effect.
Question 6
Complete
Points out of 4.00
Question text
What are the responsibilities of the officer in charge during restricted visibility?
At least 4 responsibilities
1. Inform the master
2. Post a proper lockout
3. Exhibit navigational lights
4. Operate and use the radar
Question 7
Complete
Points out of 10.00
Question text
List 10 duties and responsibilities of the officer in charge of navigation when the
vessel is at anchor.
1.determine and plot the ship’s position on the appropriate chart as soon as
practicable
2.when circumstances permit, check at sufficiently frequent intervals whether the
ship is remaining securely at anchor by taking bearings of fixed navigation marks
or readily identifiable shore objects
3.ensure that proper lookout is maintained
4. ensure that inspection rounds of the ship are made periodically
5.observe meteorological and tidal conditions and the state of the sea
6. notify the master and undertake all necessary measures if the ship drags
anchor
7. ensure that the state of readiness of the main engines and other machinery is
in accordance with the master’s instructions
8. if visibility deteriorates, notify the master
9. ensure that the ship exhibits the appropriate lights and shapes and that
appropriate sound signals are made in accordance with all applicable regulations
10. take measures to protect the environment from pollution by the ship and
comply with applicable pollution regulations
1. Lookout
A look out is a person at the ship’s bridge who maintains a continuous
watch of the sea to report any kind of hazard that can be an obstacle in the
navigation and cause harm to the ship. According to COLREG, the lookout must
be able to give full attention to the keeping of a proper lookout and no other
duties shall be undertaken or assigned which could interfere with that task in
order to inform the officer on watch about other ships, shipwreck, debris, floating
object, etc.
2. Watch arrangement
It is considered essential to the safe operation of the vessel and also allow
the ship to respond to emergencies and other situation quickly. Typical bridge
watch keeper includes look out and a deck officer who is responsible for safe
navigation of the ship.
3. Taking over the watch
It is the handling over and taking over the navigational watch on the duty
officer. The officer in charge of the navigational watch shall not hand over the
watch to the relieving officer if there is reason to believe that the latter is not
capable of carrying out the watch keeping duties effectively, in which case the
master shall be notified, relieving officers shall satisfy themselves as to the
ship’s estimated or true position and confirm its intended track, course and
speed, and UMS controls as appropriate and shall note any dangers to navigation
expected to be encountered during their watch.
4. Performing the Navigational watch
In form of essay explain these two items;
1.) What are the principles applied when keeping a watch at sea?
The master of every ship is bound to ensure that watch keeping are
adequate for maintaining safe navigational watches. Under the master’s general
direction, the officer of the watch is responsible for navigating the ship safely
during their periods of duty, when they will be particularly concerned with
avoiding collision and stranding. The officer in charge of the watch is the
master’s representative and is primarily responsible at all times for the safe
navigation of the ship and for complying with colregs.
2.) What are the principles to be observe in keeping a navigational watch on
various aspects?
Officers of the navigational watch shall be thoroughly familiar with the use
of all electronic navigational aids carried, including their capabilities and
limitations, and shall use each of these aids when appropriate and shall bear in
mind that the echo-sounder is a valuable navigational aid.
The officer in charge of the navigational watch shall use the radar whenever
restricted visibility is encountered or expected, and at all times in congested
waters, having due regard to its limitations.
The officer in charge of the navigational watch shall ensure that the range scales
employed are changed at sufficiently frequent intervals so that echoes are
detected as early as possible. It shall be borne in mind that small or poor echoes
may escape detection.
Whenever radar is in use, the officer in charge of the navigational watch shall
select an appropriate range scale and observe the display carefully, and shall
ensure that plotting or systematic analysis is commenced in ample time.
COMPILATION OF QUIZZES
D.WATCH2(MOJO)
(HALF BRIG)
LESSON 1 QUIZ
11 HOURS - how many hours of rest period is given for 77 hours in seven days a week?
Apply safe speed - during restricted visibility encountered by the OOW, what action is the least
inappropriate?
Fitness for duty - what is regulation VII/I of stcw code?
Radar practice can be carried out whenever is possible - As OOW, how often will you carry out radar
practice?
Unmanned machinery spaces - what does UMS stands for?
Take early and positive action at ample time to avoid collision - what is the action of an OOW when risk
of collision is detected from a target?
An additional rest period other than normal period of rest- what do you mean by adequate
compensatory rest period?
Administration - Who shall require that watch schedule be posted where they can be easily accessible?
To early determine risk of collision - if you’re ask why you are taking compass bearing of an
approaching vessel frequently, what will be your possible answer?
September 1, 1989 - when was the rules of the intl. Regulations for preventing collisions at sea was
applicable internationally?
1972 - on what year does the international regulations for preventing collision at sea was created?
Coastal chart - which of the information a pilot would like to know upon embarking on broad?
Look - out - A person assigned to watch and observe any hazard to navigation by sight and hearing.
Chapter III - under what chapter of the STCW code does the qualification of the engineering watch shall
be followed?
Signal pennants - the following are the requirements to check for voyage planning except one
Master, officers & ratings - who will be aware of precautions to prevent pollution of the marine
environment relevant to international and port regulations
Precaution - master, officers and ratings shall take all possible __ to prevent such pollutions to
environment.
RULE 7 - the necessity to comply with the use of radar in watch keeping is more mandated from what
rule in colregs?
That the other vessel can be observed visually from the other - how would you expound the phrase
“deemed to be in sight of one another”?
Emergency drills - which of the following circumstances where rest periods need not be maintained?
Have an alternate command with the master - you are on watch and the master is on bridge. What will
you do?
Signal pennants - the following are the requirements to check for voyage planning except one
At all times - under rule 5, how often does a look-out shall be maintained?
In doubt - what is the reason to call the master?
There is access to the working person on deck - as OOW you may be the sole look-out on the bridge,
provided this condition shall be considered.
Precaution - master, officers and ratings shall take all possible ___ to prevent such pollution to the
environment.
Morning and first watch - you are the third officer to assume the navigational watch, what routine
schedule should you follow?
DWATCH. 2 REVIEWER
Fitness for Duty
Rest Hours
STCW Section A-VIII/1 states that:
a) Administrations shall take account of the danger posed by fatigue of seafarers, especially
those whose duties involve the safe and secure operation of a ship.
b) All persons who are assigned duty as officer in charge of a watch or as a rating forming
part of a watch and those whose duties involve designated safety, prevention of pollution and
security duties shall be provided with a rest period of not less than:
o 1 a minimum of 10 hours of rest in any 24-hour period; and
o 77 hours in any 7-day period.
c) The hours of rest may be divided into no more than two periods, one of which shall be at
least 6 hours in length, and the intervals between consecutive periods of rest shall not exceed
14 hours.
d) The requirements for rest periods laid down in paragraphs 2 and 3 need not be maintained
in case of an emergency or in other overriding operational conditions. Muster, fire-fighting
and lifeboat drills, and drills prescribed by national laws and regulations and by international
instruments, shall be conducted in a manner that minimizes the disturbance of rest periods
and does not induce fatigue.
e) Administrations shall require that watch schedules be posted where they are easily
accessible. The schedules shall be established in a standardized format in the working
language or languages of the ship and in English.
f) When a seafarer is on call, such as when a machinery space is unattended, the seafarer
shall have an adequate compensatory rest period if the normal period of rest is disturbed by
call-outs to work.
Records of Rest Hours
Administration shall require that records of daily hours of rest of seafarers be maintained in a
standardized format, in the working language or languages of the ship and in English, to
allow monitoring and verification of compliance with the provisions of this section. The
seafarers shall receive a copy of the records pertaining to them, which shall be endorsed by
the master or by a person authorized by the master and by the seafarers.
Master’s Overriding Authority
Nothing in this section shall be deemed to impair the right of the master of a ship to require a
seafarer to perform any hours of work necessary for the immediate safety of the ship,
persons on board or cargo, or for the purpose of giving assistance to other ships or persons
in distress at sea. Accordingly, the master may suspend the schedule of hours of rest and
require a seafarer to perform any hours of work necessary until the normal situation has been
restored. As soon as practicable after the normal situation has been restored, the master
shall ensure that any seafarers who have performed work in scheduled rest period are
provided with an adequate period of rest.
Parties may allow exceptions from the required hours of rest in paragraphs 2.2 and 3 above
provided that the rest period is not less than 70 hours in any 7-day period.
Exceptions from the weekly rest period provided for in paragraph 2.2 shall not be allowed for
more than two consecutive weeks. The intervals between two periods of exceptions on board
shall not be less than twice the duration of the exception.
The hours of rest provided for in paragraph 2.1 may be divided into no more than three
periods, one of which shall be at least 6 hours in length, and neither of the other two periods
shall be less than one hour in length. The intervals between consecutive periods of rest shall
not exceed 14 hours. Exceptions shall not extend beyond two 24-hour periods in any 7-day
period.
Blood Alcohol Content
Each administration shall establish, for the purpose of preventing alcohol abuse, a limit of not
greater than 0.05% blood alcohol level (BAC) or 0.25 mg/l alcohol in the breath or a quantity
of alcohol leading to such alcohol concentration for masters, officers and other seafarers
while performing designated safety security and marine environmental duties.
Below are the samples of alcohol sensor used onboard the ship.
Section A-VIII/2 states that:
Watch keeping arrangements and principles to be observed
PART 1 – CERTIFICATION
1. The officer in charge of the navigational or deck watch shall be duly qualified in
accordance with the provisions of chapter II or chapter VII appropriate to the duties
related to navigational or deck watch keeping.
2. The officer in charge of the engineering watch shall be duly qualified in accordance
with the provisions of chapter III or chapter VII appropriate to the duties related to
engineering watch keeping.
Watch Keeping at Sea
Watch keeping principles in general
Watches shall be carried out based on the following bridge and engine-room resource
management principles:
with the situations;
be taken into account
when deploying watch keeping personnel;
responsibility and team roles shall be established;
ch duties shall
maintain a proper watch, making the most effective use of the resources available,
such as information, installations/equipment and other personnel;
installations/equipment, and be familiar with handling them;
information from each station/installation/equipment;
appropriately shared
by all the watch keeping personnel;
in any situation; and
charge of watch duties without any hesitation when in any doubt as to what action
to take in the interest of safety.
Additionally;
Parties shall direct the attention of companies, masters, chief engineer officers and watch
keeping personnel to the following principles, which shall be observed to ensure that safe
watches are maintained at all times.
The master of every ship is bound to ensure that watch keeping arrangements are adequate
for maintaining a safe navigational or cargo watch. Under the master’s general direction, the
officers of the navigational watch are responsible for navigating the ship safely during their
periods of duty, when they will be particularly concerned with avoiding collision and
stranding.
The chief engineer officer of every ship is bound, in consultation with the master, to ensure
that watch keeping arrangements are adequate to maintain a safe engineering watch.
Protection of marine environment
The master, officers and ratings shall be aware of the serious effects of operational or
accidental pollution of the marine environment and shall take all possible precautions to
prevent such pollution, particularly within the framework of relevant international and port
regulations.
Principles to be observed in keeping a navigational watch
The officer in charge of the navigational watch is the master’s representative and is primarily
responsible at all times for the safe navigation of the ship and for complying with the
International Regulations for Preventing Collisions at Sea, 1972, as amended.
Lookout
A proper lookout shall be maintained at all times in compliance with rule 5 of the
International Regulations for Preventing Collisions at Sea, 1972, as amended and shall serve
the purpose of:
hearing, as well as by all
other available means, with regard to any significant change in the operating
environment;
to navigation; and
in distress, shipwrecked persons, wrecks, debris and
other hazards to safe navigation.
The lookout must be able to give full attention to the keeping of a proper lookout and no
other duties shall be undertaken or assigned which could interfere with that task.
The duties of the lookout and helmsperson are separate and the helmsperson shall not be
considered to be the lookout while steering, except in small ships where an unobstructed
allround view is provided at the steering position and there is no impairment of night vision
or other impediment to the keeping of a proper lookout. The officer in charge of the
navigational watch may be the sole lookout in daylight provided that, on each such occasion:
established without doubt
that it is safe to do so;
– state of weather, visibility, traffic density; proximity of dangers to navigation; and the
attention necessary when navigating in or near traffic separation schemes; and assistance is
immediately available to be summoned to the bridge when any change in the situation so
requires.
In determining that the composition of the navigational watch is adequate to ensure that a
proper lookout can continuously be maintained, the master shall take into account all relevant
factors, including those described in this section of the Code, as well as the following factors:
other activities occurring in the area in which the vessel is
navigating;
other routeing measures;
mmediate
operating requirements and anticipated maneuvers;
the watch;
and crew;
experience of each officer of the navigational watch, and the familiarity of that
officer with the ship’s equipment, procedures, and maneuverings capability;
communication activities, and the availability of assistance to be summoned
immediately to the bridge when necessary;
systems;
eristics;
member of the watch from detecting by sight or hearing any external development;
and
arrangements and fitness for duty which has been adopted by the Organization.
Watch arrangements
When deciding the composition of the watch on the bridge, which may include appropriately
qualified ratings, the following factors, inter alia, shall be taken into account:
al hazards which may make it necessary for the officer in
charge of the watch to carry out additional navigational duties;
electronic position-indicating devices and any other equipment affecting the safe
navigation of the ship;
bridge, procedures for their use and their limitations; and
special operational circumstances.
Taking over the watch
The officer in charge of the navigational watch shall not hand over the watch to the relieving
officer if there is reason to believe that the latter is not capable of carrying out the watch
keeping duties effectively, in which case the master shall be notified.
The relieving officer shall ensure that the members of the relieving watch are fully capable of
performing their duties, particularly as regards their adjustment to night vision.
Relieving officers shall not take over the watch until their vision is fully adjusted to the light
conditions.
Prior to taking over the watch, relieving officers shall satisfy themselves as to the ship’s
estimated or true position and confirm its intended track, course and speed, and UMS
controls as appropriate and shall note any dangers to navigation expected to be encountered
during their watch.
Relieving officers shall personally satisfy themselves regarding the:
of the ship;
, weather, visibility and the effect of these
factors upon course and speed;
bridge control; and
a) the operational condition of all navigational and safety equipment being used or
likely to be used during the watch;
b) the errors of gyro- and magnetic compasses;
c) the presence and movement of ships in sight or known to be in the vicinity;
d) the conditions and hazards likely to be encountered during the watch; and
e) the possible effects of heel, trim, water density and squat on under-keel
clearance.
If, at any time, the officer in charge of the navigational watch is to be relieved when a or
other action to avoid any hazard is taking place, the relief of that officer shall be deferred
until such action has been completed.
Performing the navigational watch
The officer in charge of the navigational watch shall:
he bridge until properly relieved; and
of the master on the bridge, until informed specifically that the master has
assumed that responsibility and this is mutually understood.
During the watch, the course steered, position and speed shall be checked at sufficiently
frequent intervals, using any available navigational aids necessary, to ensure that the ship
follows the planned course.
The officer in charge of the navigational watch shall have full knowledge of the location and
operation of all safety and navigational equipment on board the ship and shall be aware and
take account of the operating limitations of such equipment.
The officer in charge of the navigational watch shall not be assigned or undertake any duties
which would interfere with the safe navigation of the ship.
When using radar, the officer in charge of the navigational watch shall bear in mind the
necessity to comply at all times with the provisions on the use of radar contained in the
International Regulations for Preventing Collisions at Sea, 1972, as amended in force.
In cases of need, the officer in charge of the navigational watch shall not hesitate to use the
helm, engines and sound signaling apparatus. However, timely notice of intended variations
of engine speed shall be given where possible or effective use shall be made of UMS engine
controls provided on the bridge in accordance with the applicable procedures.
Officers of the navigational watch shall know the handling characteristics of their ship,
including its stopping distances, and should appreciate that other ships may have different
handling characteristics.
A proper record shall be kept during the watch of the movements and activities relating to
the navigation of the ship.
It is of special importance that at all times the officer in charge of the navigational watch
ensures that a proper lookout is maintained. In a ship with a separate chartroom, the officer
in charge of the navigational watch may visit the chartroom, when essential, for a short
period for the necessary performance of navigational duties, but shall first ensure that it is
safe to do so and that proper lookout is maintained.
Operational tests of shipboard navigational equipment shall be carried out at sea as
frequently as practicable and as circumstances permit, in particular before hazardous
conditions affecting navigation are expected. Whenever appropriate, these tests shall be
recorded. Such tests shall also be carried out prior to port arrival and departure.
The officer in charge of the navigational watch shall make regular checks to ensure that:
d at least once a watch and, when
possible, after any major alteration of course; the standard and gyro-compasses
are frequently compared and repeaters are synchronized with their master
compass;
ch;
properly;
section; and
roperly.
The officer in charge of the navigational watch shall bear in mind the necessity to comply at
all times with the requirements in force of the International Convention for the Safety of Life
at Sea (SOLAS), 1974*. The officer of the navigational watch shall take into account:
control in good time to allow any potentially hazardous situation to be dealt with in
a safe manner; and
steering, it is highly dangerous to allow a
situation to develop to the point where the officer in charge of the navigational
watch is without assistance and has to break the continuity of the lookout in order
to take emergency action.
Officers of the navigational watch shall be thoroughly familiar with the use of all electronic
navigational aids carried, including their capabilities and limitations, and shall use each of
these aids when appropriate and shall bear in mind that the echo-sounder is a valuable
navigational aid.
The officer in charge of the navigational watch shall use the radar whenever restricted
visibility is encountered or expected, and at all times in congested waters, having due regard
to its limitations.
The officer in charge of the navigational watch shall ensure that the range scales employed
are changed at sufficiently frequent intervals so that echoes are detected as early as possible.
It shall be borne in mind that small or poor echoes may escape detection.
Whenever radar is in use, the officer in charge of the navigational watch shall select an
appropriate range scale and observe the display carefully, and shall ensure that plotting or
systematic analysis is commenced in ample time.
The officer in charge of the navigational watch shall notify the master immediately:
navigation mark or to obtain soundings by the
expected time;
occurs;
or any essential navigational equipment, alarm or indicator;
gency or if in any doubt.
Despite the requirement to notify the master immediately in the foregoing circumstances, the
officer in charge of the navigational watch shall, in addition, not hesitate to take immediate
action for the safety of the ship, where circumstances so require.
The officer in charge of the navigational watch shall give watch keeping personnel all
appropriate instructions and information which will ensure the keeping of a safe watch,
including a proper lookout.
Watch Keeping Under Different Conditions and in Different Areas
Watch keeping is always maintained throughout the watch in any weather
conditions:
Clear weather
The officer in charge of the navigational watch shall take frequent and accurate compass
bearings of approaching ships as a means of early detection of risk of collision and shall bear
in mind that such risk may sometimes exist even when an appreciable bearing change is
evident, particularly when approaching a very large ship or a tow or when approaching a ship
at close range. The officer in charge of the navigational watch shall also take early and
positive action in compliance with the applicable International Regulations for Preventing
Collisions at Sea, 1972, as amended and subsequently check that such action is having the
desired effect.
In clear weather, whenever possible, the officer in charge of the navigational watch shall
carry out radar practice.
Restricted visibility
When restricted visibility is encountered or expected, the first responsibility of the officer in
charge of the navigational watch is to comply with the relevant rules of the International
Regulations for Preventing Collisions at Sea, 1972, as amended with particular regard to the
sounding of fog signals, proceeding at a safe speed and having the engines ready for
immediate manoeuvre. In addition, the officer in charge of the navigational watch shall:
In hours of darkness
The master and the officer in charge of the navigational watch, when arranging lookout duty,
shall have due regard to the bridge equipment and navigational aids available for use, their
limitations, procedures and safeguards implemented.
The largest scale chart on board, suitable for the area and corrected with the latest available
information, shall be used. Fixes shall be taken at frequent intervals, and shall be carried out
by more than one method whenever circumstances allow. When using ECDIS, appropriate
usage code (scale) electronic navigational charts shall be used and the ship’s position shall be
checked by an independent means of position fixing at appropriate intervals.
The officer in charge of the navigational watch shall positively identify all relevant navigation
marks.
Navigation with pilot on board
Despite the duties and obligations of pilots, their presence on board does not relieve the
master or the officer in charge of the navigational watch from their duties and obligations for
the safety of the ship. The master and the pilot shall exchange information regarding
navigation procedures, local conditions and the ship’s characteristics. The master and/or the
officer in charge of the navigational watch shall co-operate closely with the pilot and maintain
an accurate check on the ship’s position and movement.
If in any doubt as to the pilot’s actions or intentions, the officer in charge of the navigational
watch shall seek clarification from the pilot and, if doubt still exists, shall notify the master
immediately and take whatever action is necessary before the master arrives.
Ship at anchor
If the master considers it necessary, a continuous navigational watch shall be maintained at
anchor. While at anchor, the officer in charge of the navigational watch shall:
and plot the ship’s position on the appropriate chart as soon as
practicable;
the ship is remaining securely at anchor by taking bearings of fixed navigation
marks or readily identifiable shore objects;
measures if the ship drags
anchor;
in accordance with the master’s instructions;
appropriate lights and shapes and that
appropriate sound signals are made in accordance with all applicable
regulations; and
comply with applicable pollution regulations.
Steering Control
Principle of Autopilot system
An autopilot is a mechanical, electrical or hydraulic system which can maintain a vessel on a
predetermined set or course without the need for human intervention. Using a direct or
indirect connection with a vessel’s steering mechanism, the autopilot relieves the crew from
the task of manually steering the ship.
Autopilot have evolved from simple course holding systems to adaptive computer systems
that offer reduced fuel costs and increases transit times. These new systems learn the
characteristics of the vessel’s handling and minimize rudder movement reducing drag on the
vessel. Increased speed and lower fuel consumption makes autopilot more user friendly.
Autopilots do not replace a human operator, but assist them in controlling the ship, allowing
them to focus on broader aspects of operation, such as monitoring the trajectory, weather
and systems.
o be used for large alterations of more than 15-20
which it will start to wander
of time.
Use of the Automatic Pilot
The master shall ensure that an automatic pilot, where fitted, shall not be used in area of
high traffic then density, in condition of restricted visibility nor in any other hazardous
navigational situation unless it is possible to establish manual control of the ships steering
within thirty (30) seconds.
Before entering any area of high traffic density, and whenever visibility is likely to become
restricted or some other hazardous navigational situation is likely to arise, the master shall
arrange, where practicable, for the officer of the watch to have an available without delay the
services of a qualified helmsman who shall be ready at all times to take over the manual
steering.
The change-over from automatic to manual steering and vice versa shall be made by or
under the supervision of the officer of the watch, or, if there is no such officer, the master.
The master shall ensure that the manual steering gear is tested;
a) After continuous use of the automatic pilot for 24 hours,
b) Before entering any areas where navigation demands special caution.
The working principle of autopilot system
An output from a gyro or magnetic compass is coupled to a differential amplifier along with a
signal derived from a manual course steering control. If no difference exists between the two
signals, no output will be produced by the amplifier and no movement of the rudder occurs.
When a difference is detected between the two sources of data, an output error signal,
proportional in magnitude to the size of the difference, is applied to the heading error
amplifier. Output of this amplifier is coupled to the rudder actuator circuit, which causes the
rudder to move in the direction determined by the sign of the output voltage.
The error signal between compass and selected course inputs produces an output voltage
from the differential amplifier that is proportional to the off course error. This type of control,
therefore, is termed ‘proportional’ control. As it has been shown, the use of proportional.
Different steering modes of autopilot
Auto/Manual
Allows user to select between manual steering and autopilot. Officer to steer correct course,
rudder to be on midships, course to steer set, off course alarm set before changing over to
autopilot.
Follow up
If rudder is to be put on starboard 10, helm is put on starboard 10. When helm is on midship,
rudder will return to midships.
Non-follow up
If rudder is to be put on starboard 10, helm is turned to starboard, a few degrees before
starboard 10, the helm is put on midhships, rudder then settles on starboard 10. If rudder
goes beyond starboard 10, slight port helm to be given. Rudder will remain on starboard 10
even when helm is returned to midhsip. To bring it back to midships, port helm to be given.
Off course alarm
It is fitted on the autopilot usually set for 5 to 10 degrees. If difference between actual
course and course set by officer for autopilot is more than value set for alarm, it will sound.
This alarm will not sound in case of gyro failure.
Only indication in this case is a gyro failure alarm. Gyro compass and repeaters to compared
frequently along with magnetic compass.
Disadvantages of Autopilot
keep the gyro course and wander with the gyro
alterations.
10 Things to Consider While Using Auto-Pilot System on Ships
Back in the old days of merchant shipping, the ‘Quarter Master’ was a vital member of the
Bridge team. ‘Quarter Master’ was the title given to the able bodied seamen whose primary
responsibility was to steer the ship according to the Master’s and Officer’s helm orders.
Quarter Masters kept watches and took turns on the helm all day when at sea. This practise
continued until automation took over in the field of navigation.
The significance of Quarter Master almost vanished off when the revolutionary equipment
‘Auto-Pilot’ was invented. It was during the early 1920’s when an automated steering and
helm control system was introduced onboard merchant ships.
Auto-Pilot system is considered as one of the most advanced and technically sophisticated
navigational equipment tools on ships. Auto-Pilot is synchronised with the Gyro Compass to
steer manually input courses, with reference to the gyro heading. Auto Pilot steers the
manually input course by controlling the steering gear to turn the rudder in the required
manner.
Furthermore, modern auto-pilot systems are capable of being synchronised with the
Electronic Chart system (ECDIS) enabling to follow the courses laid out in the Voyage plan.
This feature cuts out the need of manual course changes and alterations as the system will
follow the courses and alterations as per the voyage plan.
The below notes are a brief outline of 10 important points to be considered while
operating Auto-pilot system onboard for safe and smooth navigation.
1. Rate of Turn and Rudder Limits
The method of turn is the most important control of the Auto-Pilot system. The system will
use the selected turn method for course alterations. The user can input the limit of such turn
methods, which are as follows:
a. Rate of Turn
This is the most commonly used turn method. In this method, the user can set a value of
turn rate between 1-300 degrees (varies on different models). When turning, the rudder will
move as much as it takes to attain the required turn rate without exceeding the set
value. The officer must consider the vessel’s manoeuvring characteristics and set a value
safe for the vessel.
b. Rudder Limits
Rudder limit method allows the user to set a value from 1 degree to the max rudder angle. In
this method, while altering course the rudder will not exceed more than the set limit. Again,
the vessel’s manoeuvring characteristics should be considered while choosing the rudder
value.
Modern systems allow turning by radius as well. In such method the user can input turn
radius in nautical miles.
2) Steering Gear Pumps
Steering gear pumps are used to pump hydraulic oil to actuate the steering gear unit (RAM)
which in turn moves the rudder in the required direction. That means, when more pumps are
running, the rudder will move more swiftly. The number of pumps available varies as per the
steering gear unit.
The officer of watch should be aware of the pumps and use it wisely.
If operating the auto-pilot in areas with traffic density where sudden and swift alterations are
required, maximum steering gear pumps shall be running.
In ocean cruising and open sea navigation with less traffic, the pumps running shall be
reduced to its minimum.
3) Off Course Alarm
An off-course alarm serves for the purpose of notifying the operator if there is any difference
in the set course and the actual heading of the vessel. The user can manually set the
required amount of degrees, after which an alarm will sound to notify the user that the set
degree of difference has exceeded.
However, the user has to keep a check on the course changes as in some cases when the
gyro compass wanders its course, the auto-pilot will follow the wandering compass and fail to
sound the alarm.
4. Manual Mode
The steering controls of the system can be categorised as Automatic and Manual mode. It
allows the ship to be navigated either in Manual mode or Automatic mode by switching the
controls.
In Manual Mode, the vessel can be hand steered by using the Follow-Up Helm or a NonFollow
up emergency tiller.
Hand steering is used when the ship is manoeuvring, and navigating in restricted waters,
channels and areas with traffic density traffic density.
NFU tiller when used will move the rudder in a desired direction but not to a specific angle.
This is used in case of emergencies.
The user must be familiar with the procedure of inter-switching from Auto and Manual
modes.
5. Traffic Density
The use of Auto-Pilot is not recommended when navigating in areas with high traffic density,
narrow channels and traffic separation schemes and other restricted waters. The auto pilot
may not be efficient enough to turn the vessel spontaneously while navigating in such areas
demanding swift alterations and manoeuvres to avoid a collision or close quarter situation. If
the auto-pilot is used in such cases, all the steering gear pumps shall be switched on for
better rudder response.
6. Speed
The system works inefficiently on reduced speeds. The use of the auto-pilot is not
recommended when the ship is manoeuvring or steaming in very less speed.
The system allows the users to synchronise with the Speed Log to receive feeds on the ship’s
speed. The users should keep a check on the speed log as any error in the log speed will
reflect in the auto-pilot system.
The system also allows the users to manually input the speed, when doing so it is important
to set a value as close as possible to the actual speed of the vessel.
7. Weather Conditions
Rough weather and hostile sea conditions have adverse effects on the performance of the
auto-pilot. Uncontrolled yawing of the ship can result in excessive rudder movement. Modern
auto-pilot system has Weather control option in which the system automatically adjusts the
setting to adapt to the changing weather and sea conditions. It also provides an option for
the user to manual set a specific value.
8. Gyro Compass
The Auto-Pilot system is functionally dependant on the Gyro Compass. If there is any error or
fluctuation in the gyro heading, there will be an equivalent change in the course steered. In
worse cases, when gyro fails, the system will lose track on its heading and will be unable to
steer the required course.
In any case of emergency, power blackout or gyro failure the system should be immediately
changed over to Manual mode and use the helm to steer the course using Magnetic compass.
9. Important Alarms and signals
Apart from off course alarm, an auto pilot must be integrated with:
a. Failure or reduction in power alarm, which will sound in the event of auto pilot failure
or in case when there is reduction in the power supply to heading control or
monitoring system
b. Sensor status monitoring: If any of the sensors in the auto pilot system fails to
respond, it should be indicated by an audible alarm in the monitoring system
c. Heading monitor: If the ship is required to carry two independent compasses, a
heading monitor to track the current heading information by independent heading
sources must be provided. An audio-visual alarm both to be provided if the heading
information in use diverts from the second heading source beyond a set limit. It should
also be provided with clear indication of actual heading source.
10. Important Limitations
The auto pilot system must be such that the preset heading cannot be altered by intentional
intervention of onboard personal and the heading control system should change the course to
preset heading without overshooting its position
As we have stated above, auto-pilot is an undeniable boon in modern navigation. It is the
responsibility of the officers to ensure that they are completely aware of the equipment and
its features and controls to make a proper and efficient use of it. Despite the fact that autopilot
systems varies in model from ship to ship, it’s working principle and features will be the
same. Deck officers making use of the equipment are strongly recommended to read the
manufacture’s operating manual to get a thorough understanding of the equipment.
Adaptive autopilot and brief explanation of its function
An autopilot automatically adjusts the sensitivity of a ship's steering system to accommodate
changes in speed as well as sea and wind conditions. The autopilot utilizes heading error,
speed and speed squared signals to produce a rudder order signal for controlling rudder
position.
The rudder order signal is developed in a heading keeping circuit unless a heading change
greater than a predetermined threshold is commanded, in which event a programmer
substitutes a heading change circuit for the heading keeping circuit. The sensitivity of the
heading change circuit is automatically adjusted as an inverse function of vessel speed
squared, and automatic rudder order limits are established in the same circuit as an inverse
function of speed.
The sensitivity of the heading keeping circuit is adjusted in accordance with a signal from an
automatic gain control circuit which derives a performance index J from ship's speed, heading
error and rudder order signals occurring during a given measurement interval. The
performance index derived during a given measurement interval is compared with the index
derived in the previous interval and a counter register is set according to the results of this
comparison.
The heading keeping circuit receives heading error signals which are processed in a first
proportional channel and also differentiated and processed in a second or rate channel. The
attenuation in each channel is adjusted in accordance with the value stored in the counter
register. The attenuation in the rate channel is made equal to the square root of the
attenuation in the proportional channel. The modified rate and proportional signals are added
to obtain the final rudder order signal.
Changing over from manual to autopilot and vice versa
A simple operation which can be done any time by putting the switch from ‘Auto’ to ‘Manual’.
The steering must be changed from ‘Auto’ to ‘Manual’ once every watch and ship hand
steered for some time before returning to ‘Auto’
The procedure will differ from equipment to equipment, but the common generic points are:
conditions. Turn the auto-course setting pointer to the course to be steered.
ourse should be dead steady and swinging off the course at
all.
ship goes off course
Operation of Course Recorder
Course Recorder
Record keeping is very important. It provides evidence of the courses steered by the ship.
This evidence is vital for some reason an enquiry is needed, for example after an accident.
Course Recorder – this is a graphic record keeping device which can record all gyro courses
steered by the ship throughout the voyage. It has a built-in clocks which keeps time
accurately. This instrument is fitted on the ship’s bridge and is a legal requirement.
Need for a Course Recorder
the ship in case of an accident like a collision or grounding.
record of course and time cannot be maintained manually as
weather, yawing, and fluctuations in steering affect course steered. Hence the need to
have an automatic recorder.
cates whether the vessel is steering a steady course or if there
is too much wandering either due to the weather or the compass itself. If it is due to
the weather then adjustments can be made on the autopilot.
How it works
The operation of a course recorder is straightforward.
The drum consists of two sections;
-zag groove cut in it going around the drum and the other
with a continuous stepped groove running around the drum. There is also a horizontal
guide bar with a slit in it through which the pens are fitted and run.
This signal rotates the servo motor and turns the drum in the direction indicated. The
course pen moves along the zig-zag groove across the paper. If the drum turns
clockwise, the course pen will move to the left and vice versa. The zone pen will stay
in its present groove until the course has reached the junction. If the drum turns
anymore clockwise, the course pen will begin to move to the right and the zone pen
will slip into the next zone.
The course being steered can be read by simply checking where the zone pen is. Then we
use that scale on the course section of the paper to read the course being steered as
indicated be the course pen.
Understanding Steering Gear in Ships
We are all familiar with the use of a rudder, which helps in turning a ship as and when
required. Rudders are the principal system for the entire motion and control of the ships. But
we mustn’t forget that the entire rudder action is dependent on another pivotal system called
the Steering Gear.
Steering Gear integrated with the rudder system defines the complete ‘turning
mechanism’ mandatory for each and every ship irrespective of size, type and operation.
Steering gear system has been an indispensable part of the ship’s machinery since the advent
of the very early ships, which were operated by hand.
Steering Gear System in Ship
The efficiency of performance of steering gear depends on some main aspects. These basic
requirements to be invariably met by all steering gears are guided by rules set by
classification societies. They can be briefly outlined as:
from 35 degrees port to 35 degrees starboard and vice-versa with the vessel plying
forwards at a steady head-on speed for maximum continuous rated shaft rpm. and
summer load waterline within a time frame of maximum 28 seconds,
erative, the rudder shall be capable of turning 15
degrees port to 15 degrees starboard (and vice-versa) within a time frame of 1 minute
with the vessel moving at half its rated maximum speed or 7 knots (whichever is
greater) at summer load line,
or power units and the control systems are to be duplicated so that if one of
them fails, the other can easily substitute for them as standby,
power unit (hydraulic pump etc.) connected to the emergency power supply from
Emergency Generator, which shall be capable of turning the rudder from 15 degrees
from one side to other side within 60 seconds with the vessel moving at a maximum
service speed or 7 knots, whichever is greater
Types of Steering Gears on Ships
As ships continued to grow in size and became faster, modern systems easing human effort
were incorporated. Basically, there are two types of commonly used steering gear systems
present:
-hydraulic type
Though the system has undergone some major evolution, the basic physics of operation
remains the same.
The main control of the steering operations is given from the helm of any ship, similar to an
automobile where the entire control of the vehicle’s “steer-ability” rests on the steering wheel
of the driver. The ‘control force’ for turning is triggered off from the wheel at the helm, which
reaches the steering gear system.
The steering gear system generates a torsional force at a certain scale which is then, in turn,
is transmitted to the rudder stock that turns the rudder. The intermediate steering systems of
a modern day ship can be multifarious with each small component having its own unique
function. We omit to discuss each and every such component in detail.
A better illustration for the exact work sequence of in a simple rudder system is given in the
following figure
The rudder system consists of the following:
turn the rudder by applying torque
In hydraulic and electro-hydraulic systems, hydraulic pressure is developed by hydraulic
pumps which are mainly driven by electric motors (electro-hydraulic systems) or sometimes
through purely mechanical means (hydraulic systems).
However, mainly advanced electro-hydraulic systems are predominant in ships nowadays.
These hydraulic pumps play a crucial role in generating the required pressure to create
motions in the steering gear which can trigger the necessary rotary moments in the rudder
system.
Steering Control Systems
Total Steering Systems
Non-Follow-Up
A non-follow-up system actuates the solenoid valves by controlling the steering actuator.
Upon a steering request the valve(s) open completely, resulting in full force being applied to
the rudder as long as input is given. Upon removal of the steering request the valve(s) closes
again (time dependent control).
Full Follow-Up
A full follow-up system applies position feedback. The required rudder position is set on the
steering control(s), upon which the solenoid valves are opened to control the steering
actuator.
The actual position and requested position are continuously compared, resulting in automatic
closure of the valves upon reaching the desired position (position dependent control).
Types of Solenoid Valves
Bang-Bang (black/white) Solenoid Valves
Bang-Bang solenoid valves are only capable of opening and closing completely. Once opened,
full available force is applied to the rudder. Once closed, the rudder-applied force is terminated
promptly.
This results in a fast response type of characteristic.
Proportional Solenoid Valves
Proportional solenoid valves are capable of opening and closing gradually. This results in a
smooth increase of force being applied to the rudder. Upon closure of the valves, power is
gradually reduced to zero resulting in a deceleration of the actuator. This results in smooth and
accurate steering characteristics.