The Merchant Marine Circular No. 138 from the PANAMA MARITIME
AUTHORITY specifies guidelines for maintaining and testing Magnetic
Those guidelines are stated below
1. These guidelines apply to all
ships irrespective of size, and navigation area.
1. The magnetic Compass is
required under Chapter V, regulation 19, of the 2000 amendments
to 1974 the International Convention for the Safety of Life at
Sea (SOLAS), 1974. The Magnetic Compass must meet the standards
developed by the
3. Responsibility of Maintenance.
1. It is the responsibility of
the Owner/operator and the Master to ensure that compasses on
their ships are maintained in good working order to the
standards developed by the
4. When to Adjust Compasses.
1. Magnetic Compasses shall be
a) They are first installed or
b) they become unreliable,
c) the ship undergoes structural
repairs or alterations that could affect
its permanent and induced
d) electrical magnetic equipment
close to the compasses is added,
removed or altered,
e) a maximum period of one (1)
year has elapsed since the date of the
last adjustment and record of
compass deviations has not been
properly maintained or the record
of deviations are excessive or
when the compass shows physical
f) deviation exceeds five (5)
degrees taking into account the variation
of the place and the method used.
5. Effect of changes in magnetism
during the life of a ship.
1. Because the magnetism of a new
ship can be particularly unstable, the performance of
magnetic compasses should be
monitored carefully during the early life of a ship and
adjustments made if necessary.
2. Masters are advised that it is
essential to check the performance of magnetic
a) Carrying cargoes which have
b) Using electromagnetic lifting
appliances to load or discharge;
c) A casualty in which the has
been subject to severe contact or
electrical charges; or
d) The ship has laid up or has
been lying idle – even a short period of
idleness can lead to serious
deviations, especially for small vessels.
3. Further to 5.2(b), the
retentive magnetic field can alter a ship’s magnetism, making
compasses unreliable. However, a
large amount of the magnetism induced by an
electromagnetic equipment may
subsequently decay; therefore immediate
readjustment is not advised.
Every effort should be made to determine the compass
6. Monitoring Compass Performance
1. Frequent observation should be
made to determine compass error. Compass
performance should be monitored
by recording deviations in a compasses deviation
book. This may show the need for
repair, testing or adjustment or if the records are
not correctly carried out.
7. Adjustment and repairs.
1. Adjustment must be made by a
duly authorized compass adjuster. If a qualified and
certified compass adjuster is
unavailable and the master considers it necessary, then
adjustments may be made by the
Master, who should also have expertise as compass
2. The Administration of Panama
may also accept the compass adjusters recognized by
one of the States members of
SOLAS 74 Convention, who also must complete a
Compass adjustment course in a
certified center that meets the International standards
developed by the Organization;
Under no circumstances, the same person that
surveyed a vessel shall carry out
the compass adjustment. The date of any adjustment
and other details should be noted
in the compass deviation book.
3. The position of all compass
correctors should be recorded in the compass deviation
book and on deviation cards.
4. The minimum distance between
the magnetic compass and electrical panels or any
other electrical equipment such
as: Radar’s, Gyro compasses, Radios etc. will be
determined by the manufacturer of
those equipment’s, according to standards
developed by the Organization and
shall be verified by the Flag State surveyors while
surveying the ship.
5. Separate deviation cards shall
be prepared for the standards compass and the
transmitting magnetic compass
repeater, if fitted, by comparing headings.
6. After the adjustment, the
vessel must be provided with a certificate of compass
adjustment that must include the
deviation table and this document must include a
least: the name of the vessel
/IMO # / call letters / flag / place where the job is carried
out, name of the adjuster / stamp
/ sign; maker of the compass, sea and weather
conditions, method used,
numerical and graphical results of deviation after correction.
7. Repairs should only be made by
a compass manufacturer or other competent and
authorized company using proper
test facilities. When the work is finished, the
repairer should supply the Owner
or Master with a certificate specifying that the work
was carried out in accordance
with the international standards for magnetic
8. Portable Equipment that may
interfere with compasses.
1. Master and Officers are
advised that portable electrical equipment (e.g. radios and
tape recorders or items made of
steel can affect the performance of a compass. Care
should be taken to ensure that
such items are kept away from the compass position
9. Spare Bowl.
1. If a spare magnetic compass
bowl is required, then it should be carefully stowed
together with its gimbals units
away from the bridge structure so that they are
unaffected by any casualty
disabling the bridge.
10. Transmitting Magnetic
1. If a new or existing standards
magnetic compass is modified to provide a
transmission output then the
device must be certified or re-certified with the
transmitting element in place.
2. Modifications should be made
by an experienced compass technician, who shall
ensure that the transmitting
element is compatible with the binnacle. The
performance of the equipment
cannot be relied upon until the compass has been recertified
(as described above) and
adjustment have been made by a compass adjuster.
3. Auxiliary equipment included
in the modifications (e.g. electronic units, displays and
power supplies) should be
type-tested to establish safe distances from the compass.
In particular, care should be
taken to avoid the effect on the compass of spurious
radio frequency transmissions.
For guidance, refer to IMO Resolution A.813 (19)
and Resolution A.694 (17)
If a transmitting magnetic compass
provides heading information, i.e. it is read by the helmsman
at the main steering position, then
the spare bowl must be fitted with a transmitting element, and
individual testing is required.
Alternatively, if heading information is provided by the reflected
image of a standard compass periscope
or by a separate steering compass, and a transmitting
compass is fitted voluntarily to
provide a repeater facility to navigation equipment, then the
spare bowl not require a separate
Revised August 2009
Inquiries concerning the subject of
this Circular or any request should be directed to:
Directorate General of Merchant
Marine, New York Office
International Representative Office
48th Street, 11 floor
New York, NY 10036
Phone: ++1 (212) 869-6440
Fax: ++1 (212) 575-2285/2288