ISO 19019:2005

INTERNATIONAL ISO
STANDARD 19019
First edition
2005-04-15
Sea-going vessels and marine
technology — Instructions for planning,
carrying out and reporting sea trials
Navires de haute mer et technologie marine — Instructions pour la
planification, l'exécution et le compte rendu d'essais en mer

Reference number
©
ISO 2005
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

©  ISO 2005
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2005 – All rights reserved

Contents Page
Foreword. v
1 Scope. 1
2 Normative references . 1
3 General information on sea trials. 2
3.1 General. 2
3.2 Responsibility for sea trials . 2
3.3 Demonstration of operability . 3
3.4 Demonstration of performance and economy . 3
3.5 Demonstration of endurance . 3
3.6 Applicability. 3
4 Planning of sea trials . 3
4.1 Actions required in preparing for sea trials . 3
4.2 Sequence of sea trials . 4
4.3 Safety precautions . 4
4.4 Trials which shall be completed before sea trials . 5
4.5 Pre-trial meeting. 5
4.6 Final meeting . 6
5 Propulsion trials. 6
5.1 Speed trial. 6
5.2 Fuel consumption trial. 8
5.3 Endurance trial . 9
5.4 Astern trial . 10
6 Control system trials . 11
6.1 Steering gear trials. 11
6.2 Thrusters trials . 13
6.3 Fin stabilizers trial. 14
7 Manoeuvring trials . 16
7.1 Purpose. 16
7.2 Trials specification. 16
7.3 Restrictions to the execution of the trials . 17
7.4 Instrumentation required for the trials. 17
7.5 Trials execution. 17
7.6 Data to be monitored and recorded . 18
7.7 Reporting of data . 18
8 Miscellaneous tests . 19
8.1 Anchor-handling test . 19
8.2 Structure vibration tests. 20
8.3 Noise level test . 21
Annex A (normative) Trial acceptance document. 22
Annex B (normative) Sea trials . 23
Annex C (normative) Normal sequence of sea trials . 25
Annex D (informative) Sea trials — Propulsion plant data sheet . 26
Annex E (informative) Speed and economy trials. 27
Annex F (informative) Steering gear trials . 28
Annex G (informative) Data sheet for thrusters test . 29
Annex H (informative) Data sheet for stabilizer sea trials .30
Annex I (normative) Manoeuvring trials — Data required .31
Annex J (informative) Data sheet for manoeuvring trials.32
Annex K (informative) Data sheet for anchor-handling test.33
Annex L (normative) Data sheets for noise tests .34
Bibliography.36

iv © ISO 2005 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 19019 was prepared by the European Committee for Standardization (CEN) Technical Committee
CEN/TC 300, Sea-going vessels and marine technology, in collaboration with Technical Committee ISO/TC 8,
Ships and marine technology, Subcommittee SC 9, General requirements, in accordance with the Agreement
on technical cooperation between ISO and CEN (Vienna Agreement).
INTERNATIONAL STANDARD ISO 19019:2005(E)

Sea-going vessels and marine technology — Instructions for
planning, carrying out and reporting sea trials
1 Scope
This International Standard provides ship owners, designers, shipbuilders and trial crew with basic instructions
for the planning, carrying out and reporting of sea trials.
This International Standard provides general information for achieving a unified format for sea trials to be
executed as identified in the contract.
This International Standard is applicable to sea trials generally adopted for types of mechanically propelled
vessels as indicated in Annex B.
This International Standard is not applicable to submarines.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 2923, Acoustics — Measurement of noise on board vessels
ISO 3046 (all parts), Reciprocating internal combustion engines — Performance
ISO 4867, Code for the measurement and reporting of shipboard vibration data
ISO 4868, Code for the measurement and reporting of local vibration data of ship structures and equipment
ISO 6954, Mechanical vibration — Guidelines for the measurement, reporting and evaluation of vibration with
regard to habitability on passenger and merchant ships
ISO 15016, Ships and marine technology — Guidelines for the assessment of speed and power performance
by analysis of speed trial data
DIN 81208-2, Manoeuvring of ships — Part 2: Coasting stop trial
DIN 81208-3, Manoeuvring of ships — Part 3: Pull-out trial
DIN 81208-4, Manoeuvring of ships — Part 4: Acceleration trial
DIN 81208-5, Manoeuvring of ships — Part 5: Turning circle test/trial
DIN 81208-6, Manoeuvring of ships — Part 6: Accelerating turn test/trial
DIN 81208-8, Manoeuvring of ships — Part 8: Zig-zag test/trial (Z-test/trial)
DIN 81208-10, Manoeuvring of ships — Part 10: Reverse spiral test/trial (according to Bech)
DIN 81208-11, Manoeuvring of ships — Part 11: Direct spiral test/trial (according to Dieudonné)
DIN 81208-12, Manoeuvring of ships — Part 12: Stopping trial
DIN 81208-13, Manoeuvring of ships — Part 13: Traversing test/trial
DIN 81208-23, Manoeuvring of ships — Part 23: Turning test/trial with thrusters
DIN 81208-24, Manoeuvring of ships — Part 24: Course change test/trial
DIN 81208-25, Manoeuvring of ships — Part 25: Parallel track test/trial
DIN 81208-26, Manoeuvring of ships — Part 26: Man-overboard trial
IMO Resolution A.468 (XII), Code on Noise Levels on Board Ships
International Convention for the Safety of Life at Sea (SOLAS), 1974
3 General information on sea trials
3.1 General
The aim of sea trials is to demonstrate that the vessel is in conformity with contract and with requirements of
classification societies and flag authorities.
Sea trials are mainly functional, to demonstrate operation, behaviour, energy consumption and required power
of the vessel, her systems, equipment and components. Sea trials shall be executed in a suitable area in
order to avoid risks of collisions, damages and interruptions.
Sea trials are of two sorts:
a) global trials, which include propulsion trials, manoeuvring trials, structure vibration tests and noise level
tests;
and
b) system trials, which include those non-global trials that cannot be done as quay trials, e.g. anchor-
handling tests.
Only global trials and certain system trials are covered by this International Standard.
If necessary, the measured data should be recorded continuously, e.g. using a computer with a certain
frequency of sampling (e.g. frequency of 1 Hz for speed trials). It is important to carry out an uncertainty
analysis.
3.2 Responsibility for sea trials
The shipbuilder is responsible for planning, conducting and evaluating the sea trials.
Trials may be conducted by institutions acknowledged as competent to perform those trials, as agreed
between the shipbuilder and the owner.
Instruments and equipment to be used on trials shall be calibrated and documented as traceable to
international standards of measurement.
A trials report shall be prepared with necessary recorded data sheets, as well as all terms of acceptance, in
accordance with Annex A.
2 © ISO 2005 – All rights reserved

The individual sheets of the trials report shall be signed by the participants, confirming that it correctly reports
the trials results.
The trials report original shall remain in possession of the shipbuilder, and authentic copies shall be delivered
to the owner and the Classification Society, as applicable.
3.3 Demonstration of operability
Some systems, such as ship propulsion and control systems, can be shown to operate in their design modes
only at sea. This demonstration of operability verifies that
a) all systems are correctly connected,
b) the mode of operation and conduct of the systems agree with specifications,
c) there are no obstructions, leakage or other symptoms of malfunction.
3.4 Demonstration of performance and economy
During sea trials concerning the propulsion system, the aim is to confirm that the agreed power rating is
attained and that the corresponding ship speed and propulsion engine output are those stipulated by the
contract and correspond to speed and power of propulsion model tests, if available.
These trials shall be carried out in a specified reference load condition.
3.5 Demonstration of endurance
During endurance trials, the aim is to verify the ability of the system to operate in the specified mode for the
time necessary to develop thermal equilibrium conditions and to allow detection of any inadequacies.
3.6 Applicability
For economic reasons and technical interest, it is convenient to analyse which trials should be performed on
each type or series of ships (sister ships in series).
Lists of trials recommended for first-of-a-class that can be omitted for sister ships shall be specified in the
contract.
Annex B presents Table B.3 which indicates in general the trials for different types of ship. In each case and
taking into account specific conditions of each ship, those trials which are to be conducted shall be specifically
defined in the contract.
4 Planning of sea trials
4.1 Actions required in preparing for sea trials
The shipbuilder responsible for sea trials shall carefully plan these trials, so they are carried out with the
necessary safety measures in an accessible and adequate geographic area, in the strict minimum period of
time and with unequivocal results accepted by all participants.
Planning shall assure that trials are carried out with respect to the following items.
a) All permits and certificates needed to go to sea have been obtained.
b) All needed insurance policies have been obtained.
c) All qualified personnel needed for operating the ship, and all engines, systems and equipment needed
during the trials, have been ordered.
d) All regulatory bodies, Classification Society, ship owner, ship agents, suppliers, subcontractors, harbour
facilities, departments delivering provisions, fuel, water, towing, etc., needed for conducting the sea trials,
have been informed.
e) All safety measures have been checked and all fixed, portable and individual material (for crew, trial
personnel and guests) is on board and operative.
f) Dock trials of all systems, as well as all tests of alarms, warning and safety systems, have been executed.
g) An inclining test has been performed, or at least a preliminary stability book has been approved, covering
the sea trials condition, in accordance with 74 SOLAS Convention, as amended.
h) Provisional calibration of magnetic compass has been completed.
i) Calibration of the radio direction finder has been completed, if installed.
The actions indicated in h) and i) may be performed just before all other sea trials.
4.2 Sequence of sea trials
An example of sequence of sea trials is given in Annex C.
4.3 Safety precautions
Sea trials shall be held only after a careful check of all ship safety devices.
There shall be sufficient lifeboats and/or life-rafts and lifejackets for all personnel on board, their number and
make shall be in accordance with the requirements of the Maritime Authority of the trial area.
All personnel on board shall be told what to do in case of abandoning ship, in particular how to use lifejackets.
A list of all personnel on board shall be communicated to the Maritime Authority of the trial area.
Everyone on board shall be assigned a station in case of fire alarm, flooding and abandoning ship; all these
details shall be indicated in a provisional muster list.
All fire detection and fighting systems shall be installed and operative.
All bilge systems, fixed and portable, shall be installed, tested and operative.
All alarm, safety and warning devices shall be installed, tested and duly identified.
All external communication devices, both normal and emergency, and corresponding power feeders shall be
installed, tested and operative.
All lifeboat and life-raft launching systems shall be installed, tested and operative.
Sea-trial crew shall be well aware of all safety devices and shall have specific instructions for acting in an
emergency or abandonment, with special attention to assist all persons on board not belonging to the crew.
4 © ISO 2005 – All rights reserved

4.4 Trials which shall be completed before sea trials
Sea trials shall be executed after completion of all installations, builder's trials, dock tests and trials, in
particular for the following:
 main engines and all their command, control, alarm, safety and warning devices;
 electric generators, including emergency generator, and their command, control, alarm, safety and
warning devices;
 steering gear and its emergency and alarm devices;
 navigation and signal light systems;
 whistle;
 signalling lamps;
 power, lighting and emergency electric installations;
 normal and emergency radio external communications;
 magnetic compass;
 flags, shapes, pyrotechnics and cable gear for seesaw;
 gyrocompass, radar, radio direction finder and depth sounding device and navigation platform (if
installed);
 compressed air system (if installed);
 internal telephone network, voice pipes and intercommunicators (as appropriate);
 winches and capstans;
 anchors and chains.
The use of a previously fixed check list is recommended, including all systems and equipment that are
required to be installed and tested before sea trials.
4.5 Pre-trial meeting
Before commencing sea trials, the following matters shall be addressed and agreed upon and, if considered
necessary, shall be discussed in a pre-trial meeting:
a) objectives to be attained by executing sea trials;
b) execution details;
c) selection, approval, installation and definition of calibration standards of measurement equipment and
instruments;
d) partition of responsibilities and execution of operational and control tasks of trials;
e) programme, area, duration and timetable of trials;
f) conditions and operating methods during trials;
g) correction methods to be used due to differences between specified conditions and conditions during
execution;
h) acknowledgement and approval of records procedures.
4.6 Final meeting
A final meeting involving the owner, the shipbuilder and all concerned authorities, shall be held after sea trials
are completed, in order to finalise the acceptance protocol.
5 Propulsion trials
5.1 Speed trial
5.1.1 Purpose
A speed trial is held to verify fulfilment of contractual obligations regarding ship speed and shaft power at
certain draughts (preferably related to ship model test draughts). The relationship between ship speed, shaft
power, shaft revolutions per minute and/or propeller pitch settings for controllable-pitch propellers should take
the form of plots or tables.
5.1.2 Trial specification
Whenever possible, execution and analysis shall be in accordance with ISO 15016.
If no specific conditions are invoked by the contract, speed trials shall be conducted with propulsion engines
delivering normal continuous power, and at other speed points corresponding to lower powers which are
intended to be used in future operation of the ship, and which may be used to work out shaft rotational speed
tables and/or propeller pitch settings, as appropriate. Reduced loading of the propeller shall be taken into
account.
When an overload trial of main engines has not been held during factory acceptance tests, it may be held
during this trial if the requested technical conditions are met. Reduced loading of the propeller shall be taken
into account.
Corrections on main engine performance due to differences between trial conditions and contract reference
conditions shall be established in accordance with ISO 3046 (all parts).
During speed trials, any propulsion engine power take-off for auxiliaries which are not part of the propulsion
system shall be clearly identified.
For propulsion engines with maximum continuous power above 2 000 kW, a torsion meter is recommended
for measuring power output.
5.1.3 Restrictions to the execution of the trial
Whenever possible, water depth in the trial area shall be in accordance with ISO 15016.
Whenever possible, conditions of wind and sea state shall be in accordance with ISO 15016.
5.1.4 Instrumentation required for the trial
The following instruments are needed in particular for this trial:
a) torsion meter, duly calibrated and zero setting checked before and after test (if propulsion system power
W 2 000 kW);
b) stop watches;
c) tachometer;
6 © ISO 2005 – All rights reserved

d) electronic positioning system (DGPS, GPS, trisponder or equivalent);
e) anemometer.
5.1.5 Trial execution
The following provisions shall be respected.
a) Speed trials shall be executed in an area with sufficient depth of water. In the case of limited water depth,
depth changes in the trial area shall be avoided.
b) A well-defined length and trajectory of the runs for the trial shall be established. Double runs should
preferably be made with head and tail winds.
c) The chosen runs shall not cross navigation routes or active fishing grounds.
d) The length of the runs established by location of land markers shall be between half a mile (for small craft
only) and two miles. Reference bearings should preferably be defined by parallel alignments, themselves
perpendicular to the defined runs.
e) The length of the runs established by electronic positioning systems shall preferably be equivalent to
between 5 min and 10 min measuring time or to between 1 mile and 2 miles measuring distance, the
measuring point of all double runs being the same as far as possible and the chosen measurement
system having a precision deviance of less than 20 m.
f) Since in case e) the course of the runs is more flexible, a course shall be chosen such that wind effects
are less important. Beam-relative wind is not recommended, because this could cause yawing and
pronounced rolling. As discussed in b) above, head and tail winds are preferable.
g) Independently of the speed to be verified by contractual obligation, the number of runs executed shall be
in accordance with ISO 15016.
h) For ships fitted with controllable-pitch propellers, speed trial(s) may normally be executed for more than
one propeller-pitch setting.
i) Each chosen speed condition shall correspond to normal ship operating conditions; in the case of ships
with more than one shaft, a speed condition corresponding to only one driven shaft may be chosen in
addition.
j) Shaft rotational speed should be obtained from readings of the revolution counter at the beginning and at
the end of each run.
k) The approach run to the measured course shall be long enough to give steady conditions of course, shaft
rotational speed and ship speed before commencing measurements.
l) As far as practicable, speed trials should be performed at displacement and draught conditions which are
comparable to those of a model test, provided such test results are available.
5.1.6 Data to be monitored and recorded
During the trial, the following data shall be monitored and recorded:
 area of trial;
 date, time and duration of trial, for each run;
 mean water depth in area of trial, for each run;
 sea conditions, for each run;
 wind conditions, for each run;
 draught forward, amidships and aft;
 displacement;
 current conditions (optional), for each run;
 heading, for each run;
 rudder angle, for each run;
 shaft torque (when specified), for each run;
 shaft power (when specified), for each run;
 propeller(s) rotational speed, for each run;
 propeller(s) pitch (controllable-pitch propeller), for each run;
 speed over the ground, for each run;
 speed through the water (mean of reverse runs), for each run;
 time elapsed since last hull cleaning;
 hull surface condition;
 sea water temperature and density (in the case of deep-draught ships, it should be measured at two
depths, i.e. at the water surface and at the cooling water inlet, and the mean value taken);
 operating data for propulsion engines, including fuel temperature.
5.1.7 Reporting of data
Trial data shall be reported on data forms such as the tables of ISO 15016.
5.2 Fuel consumption trial
5.2.1 Purpose
If stipulated in the contract, a fuel consumption trial shall be held to verify fulfilment of specified fuel
consumption corresponding to delivered power at specified loading conditions.
The relation between fuel consumption and shaft power or shaft rotational speed/propeller pitch settings,
respectively, shall take the form of plots or tables.
5.2.2 Trial specification
If no specific conditions are invoked in the contract, the fuel consumption trial shall be conducted with
propulsion engines delivering normal continuous rating.
8 © ISO 2005 – All rights reserved

5.2.3 Restrictions to the execution of the trial
These restrictions are identical to those given in 5.1.3.
5.2.4 Instrumentation required for the trial
The following instruments are needed in particular for this trial:
a) torsion meter (optional), duly calibrated and the zero setting checked before and after the test;
b) fuel meters, duly calibrated;
c) stop watches;
d) tachometer;
e) anemometer.
5.2.5 Trial execution
The following provisions shall be respected.
a) The fuel consumption trial shall be executed in an area with sufficient depth of water. The chosen run
shall not cross navigation routes or active fishing grounds.
b) Two samples of the fuel shall be taken before the sea trial, at the fuel oil service pump discharge or at an
equivalent station. These samples shall be duly sealed and one shall be analysed in advance of the sea
trial.
c) The status of auxiliaries shall be clearly defined.
5.2.6 Data to be monitored and recorded
The data indicated in 5.1.6 shall be monitored and recorded, with the addition of fuel consumption data.
5.2.7 Reporting of data
Trial data shall be reported on data forms such as Annexes D and E.
5.3 Endurance trial
5.3.1 Purpose
Endurance trials are held to demonstrate that the main propulsion system and its auxiliaries are able to
function well at specified conditions of agreed continuous power for a prescribed period, sufficient to develop
equilibrium conditions and reveal inadequacies, if any, of the system including its auxiliaries.
5.3.2 Trial specification
If no specific conditions are invoked by the contract or the Classification Society, the endurance trial should be
conducted with main propulsion engines operating at agreed power output, at the specified load and for a
period of 4 h.
5.3.3 Restrictions to the execution of the trial
Restrictions to the execution of the trial may be
a) disturbance, due to marine traffic or inadequate environmental conditions, which causes inconsistent
immersion of the propeller(s), or
b) seakeeping, which is critical for the safety of the vessel.
5.3.4 Instrumentation required for the trial
All instruments needed to read and record data mentioned in 5.3.6 are required.
5.3.5 Trial execution
Before the start of the measurements, proper operation and status of relevant auxiliaries and fuel meter(s)
shall be checked; existing by-passes shall be closed.
5.3.6 Data to be monitored and recorded
During the trial, particular attention shall be given to the temperature and pressure equilibrium of main
propulsion engines and their auxiliary engines. Relevant data shall be recorded.
The system and auxiliaries shall be carefully observed for potential leakage, heating, vibrations and abnormal
noises. Relevant data shall be recorded.
The behaviour and equilibrium of automatic regulating and control systems shall be verified.
5.3.7 Reporting of data
Trial data shall be reported on data forms such as Annex D.
5.4 Astern trial
5.4.1 Purpose
An astern trial is held to demonstrate that the main propulsion system is able to function well at specified
conditions of permissible astern power for an adequate period, sufficient to develop steady conditions and
reveal any inadequacies or anomalies in the system.
5.4.2 Trial specification
If no conditions are specified, the astern trial shall be conducted with the main propulsion engines delivering
permissible astern power, at the specified load.
5.4.3 Restrictions to the execution of the trial
Restrictions to the execution of the trial may be the environment conditions critical for the safety of the vessel.
5.4.4 Instrumentation required for the trial
All instruments needed to read and record data mentioned in 5.4.6 are required.
10 © ISO 2005 – All rights reserved

5.4.5 Trial execution
The difficulty of the astern trial is to keep a constant load on the propeller despite draught variations provoked
by pitching and by waves.
As astern steering is difficult, the trial shall be held at an approximately constant heading which shall be
chosen with respect to a favourable direction to wind and seaway. This depends on the above-water profile of
the vessel.
Recommended heading conditions: either superstructure all aft (head wind) or superstructure all forward (tail
wind).
5.4.6 Data to be monitored and recorded
During the trial, particular attention shall be given to reduction gear (if installed), thrust block and forward
stuffing box of the stern tube. In particular, any heating, abnormal vibrations and noises shall be recorded.
5.4.7 Reporting of data
Trial data shall be reported on data forms such as Annex D.
6 Control system trials
6.1 Steering gear trials
6.1.1 Purpose
Steering gear trials are performed to verify the performance of the steering gear and to demonstrate its
efficiency.
6.1.2 Trials specification
If the loading condition is not contractually specified, steering gear trials shall be conducted at a displacement
as close as reasonably possible to full-load displacement for merchant ships and warships.
Speeds shall be full ahead and, if specified, full astern, respectively.
NOTE The full-astern steering gear trial is in general not applicable to merchant ships.
6.1.3 Restrictions to the execution of the trials
Steering gear trials shall be executed in an area of little traffic that allows the trials to be performed without
interruption and risk of collision or causing material damage as can occur in e.g. traditional fishing grounds
with submerged nets, hook lines, etc.
6.1.4 Instrumentation required for the trials
All instruments needed to read and record data listed in 6.1.6 are required.
6.1.5 Execution of the trials
6.1.5.1 Ahead-steering-gear trial
With the main propulsion engines delivering maximum continuous rating ahead or at the corresponding shaft
speed, the following rudder manoeuvres shall be executed. The first direction of rudder movement, i.e. port or
starboard, shall be at the discretion of the trial captain, considering the conditions in the area. The following
description is for first rudder deflection to port.
a) Amidships to 35° port — Hold for sufficient duration in order to record time taken, at the steering gear,
between rudder amidships and 30°;
b) 35° port to 35° starboard — Hold approximately 10 s; record time taken, at the steering gear, between
35° hardover to 30° to the opposite side (as the steering gear is slowing down between 30° and
hardover);
c) 35° starboard to 35° port — Hold approximately 10 s; record time taken between 35° starboard and 30°
port;
d) 35° port to amidships — Record time taken between 35° port and rudder amidships;
e) trial completed.
This trial shall be repeated for each power unit of the steering gear and, if possible, for both units acting
together. For emergency power units, trials shall be performed at reduced speed and reduced rudder angles.
Setting of the propulsion plant of a single-screw main propulsion system shall not be changed during the trial;
however, change in throttle adjustment or propeller pitch in the case of a controllable-pitch propeller plant or
multi-screw main propulsion systems is permissible during the trial to avoid overload or overspeed.
If the maximum rudder angle is less than 35°, the maximum possible rudder angle shall be used, with time
determined to the maximum angle minus 5°, as above.
6.1.5.2 Astern-steering-gear trial
With the ship moving astern and main engines delivering maximum permissible astern power or the ship at
maximum permissible astern speed, the following rudder manoeuvres shall be executed:
a) Amidships to δ ° port (the maximum astern rudder angle δ ° chosen depends on the type and size of
vessel: for vessels with length of more than 80 m, δ = 15° is proposed) — Hold for sufficient duration in
order to record the time taken at the steering gear;
b) δ ° port to δ °starboard — Hold approximately 10 s;
c) δ ° starboard to δ ° port — Hold approximately 10 s;
d) δ ° port to rudder amidships;
e) trial completed.
Procedures concerning power units of the steering gear are to be analogous to those described under the
ahead steering gear trial (6.1.5.1).
12 © ISO 2005 – All rights reserved

6.1.6 Data to be monitored and recorded
6.1.6.1 Ahead-steering-gear trial
The following data shall be recorded:
a) steering gear power unit in use;
b) variations in fuel throttle setting;
c) rudder angle;
d) time required for each rudder movement;
e) maximum oil pressure on steering gear ram;
f) oil pressures on steering gear system, if manometers have been installed;
g) operation data of electric motors acting on steering gear oil pumps, either in idle or maximum power;
h) weather, wind velocity and direction, and sea condition;
i) ship speed at the start of first rudder movement;
j) propeller speed at the start of first rudder movement.
6.1.6.2 Astern-steering-gear trial
The data listed in 6.1.6.1 shall be reported.
6.1.7 Reporting of data
Trials data shall be reported on data forms such as Annex F.
6.2 Thrusters trials
6.2.1 Purpose
Thrusters trials are held to verify correct operation of the system and to demonstrate that its characteristics
satisfy the contract.
Results of these trials are important in providing information for IMO Resolution A.601 (15).
6.2.2 Trials specification
In addition to verifying functionality of the system, the trials are held to measure consumption (when
electrically driven) or operating pressures and eventually flows (when hydraulically driven), with the thrusters
running at the load conditions specified by the contract.
It is recommended that vibration and noise levels created by thrusters be measured during the trials and
compared with specified values, if defined.
6.2.3 Restrictions to the execution of the trials
Thrusters trials should preferably be executed in calm wind and sea conditions, not exceeding Beaufort 3 to 4,
Sea State 2 to 3.
6.2.4 Instrumentation required for the trials
Electronic positioning equipment (trisponder, GPS or equivalent) is required.
6.2.5 Trials execution
The following trial manoeuvres shall be carried out:
a) bow thruster
Turning trial: with the ship dead-in-water and heading into the wind, the bow thruster shall operate at full
thrust for the time it takes to turn 90° to one side and back to the initial position; operation shall be
repeated to the other side.
b) rudder thruster (active rudder)
1) moving ahead: with main propulsion system stopped, thruster shall operate with rudder amidships;
this trial shall last about 10 min for each of the following conditions: half thruster power and full
thruster power;
2) steering trial: identical to bow thruster trial, with a rudder thruster angle of 20° to each side.
c) other thruster types
To be specified according to purpose of the ship in question.
6.2.6 Data to be monitored and recorded
The following data shall be recorded:
a) bow and stern thrusters
Turning trial: Time needed for executing 90° turns in either direction, and power unit operation data, shall
be measured and recorded.
b) rudder thruster (active rudder)
1) ship's true track and attained speed shall be measured and recorded;
2) recordings identical to those indicated for bow thruster steering trial shall be carried out.
c) other thruster types
To be defined according to their type.
6.2.7 Reporting of data
Trials data shall be reported in data forms such as Annex G.
6.3 Fin stabilizers trial
6.3.1 Purpose
The fin stabilizers trial is held to verify correct operation of the fin unit(s) from the individual stabilizer
compartment(s) and to demonstrate the stabilizer(s)' performance and ship-stabilizing ability from the ship
bridge control panel.
14 © ISO 2005 – All rights reserved

6.3.2 Trial specification
In addition to verifying functionality of the system by performing local control operation trials, which include
such trials as housing and extension of the fin(s), fin(s) tilting and emergency housing of the fin(s), the sea
trials are held to demonstrate the power of the fins and to provide a comparison between the ship's natural
righting motion and the stabilized righting motion.
6.3.3 Restrictions to the execution of the trial
Any restrictions shall be agreed between shipbuilder and owner.
6.3.4 Instrumentation required for the trial
The following instrumentation is required:
a) stop watches;
b) all instruments needed to read and record data as required in 6.3.6.
6.3.5 Trial execution
6.3.5.1 Local control operation trials
The following trial manoeuvres shall be carried out:
a) housing and extension trial
With the ship at maximum speed, extend and house the fin(s) from the local control unit, and record the
time taken, maximum pressure and maximum motor current during the extension and housing sequences.
b) fin(s) tilting trial
With the ship at the fin(s) design speed, activate the local control unit hard over test to tilt the fin(s), and
record nose-up and nose-down hard-over times, maximum nose-up and nose-down pressures and
maximum nose-up and nose-down motor currents.
c) emergency housing trial
With the ship sailing at a specified speed of e.g. 10 knots, and the fin(s) extended, use the emergency
motor and the manually operated tilt and house valves to centre and house the fin(s), and record the time
taken and the maximum pressure for the housing sequence.
6.3.5.2 Sea trial modes
The control system normally provides automatic set-up and demonstration modes during sea trials. These
modes employ the fins to roll the ship. The roll angle is limited to approximately 10° to either side. At the end
of a successful set-up or demonstration, the control system reverts to stabilizing the roll motion of the ship.
a) Forced-roll demonstration
This trial demonstrates the power of the fins and
...