Tag Archives: MSC Circ 982

Bridge Visibility- Regulation 22 of SOLAS V

Navsregs>SOLAS>SOLAS V>Bridge Visibility

Bridge front of a ship

A Handy Guide

A good visual lookout is the foundation of a navigational watch.  It therefore forms the most important element of a bridge design, and is subject to its own SOLAS regulation. This post looks at that SOLAS regulation, and the related IMO  guidelines. 

Rule 5 Collision Regulations- Lookout

“Every vessel shall at all times maintain a proper look-out by sight and hearing as well as by all available means appropriate to the prevailing circumstances and conditions so as to make a full appraisal of the situation and risk of collision.”

What ships need to comply with Regulation 22 of SOLAS V?

Ships of not less than 55 metres in length constructed after 1st of July 1988.

Field of view

How close should an officer of the watch be able to see ahead?

The view of the sea surface from the conning position shall not be obscured by:

  • More than two ship lengths


  •  500 metres

Whichever is the less, forward of the bow to 10° on either side under all conditions of draught, trim and deck cargo.

How large can blind sectors be forward of the beam?

  • No single blind arc shall exceed 10°.
  • Total blind sectors shall not exceed  20°.
  • Clear sectors between blind arcs shall be at least be  5°
  • In the view 10 either side of bow no sector should exceed  5°

These figures are important to remember when loading deck cargo.

How big must the horizontal field of vision be from the conning position?

An arc of not less than 225°, that is from right ahead to not less than 22.5°, abaft the beam on either side of the ship.

These values align with the Collision Regulations definition of an overtaking vessel, and the masthead light sectors.

Collision Regulations Rule 13(b)-Overtaking

“A vessel shall be deemed to be overtaking when coming up with another vessel from a direction of more than 22.5 abaft her beam, that is, in such a position in reference to the vessel she is overtaking, that at night  she would be able to see only the strern light of that vessel but neither of her sidelights.”

Bridge of a ship in Bidston Docks

How big should the field of vision be from the bridge wings?

  • An  arc at least 225°, that is from at least 45° on the opposite bow through right ahead and then from right ahead to right astern through 180° on the same side of the ship
  • The ship’s side shall be visible from the bridge wing

What should the horizontal field of vision be from the main steering position?

Over an arc from right ahead to at least 60° on each side of the ship.

An old Tug's bridge windowThe Bridge Windows

How tall should bridge windows be?

  • The lower edge of the navigation bridge front windows above the bridge deck shall be kept as low as possible.
  • In no case shall the lower edge present an obstruction to the forward view as required in the regulation.
  •  The upper edge of the navigation bridge front windows shall allow a forward view of the horizon, for a person with a height of eye of 1.8 metres above the bridge deck at the conning position, when the ship is pitching in heavy seas.

What are the requirements of bridge Windows?

  • The bridge front windows shall be inclined from the vertical plane top out, at an angle of not less than 10° and not more than 25°.
  •  Framing between navigation bridge windows shall be kept to a minimum and not be installed immediately forward of any work station.
  • Polarised and tinted windows shall not be fitted.
  •  A clear view through at least two of the navigation bridge front windows shall be provided.

Ballast water exchange and bridge visibility

When can ballast water exchange be conducted?

  • When the master has determined that it is safe to do so and takes into consideration any increased blind sectors or reduced horizontal fields of vision resulting from the operation to ensure that a proper lookout is maintained at all times
  • When the exchange is conducted in accordance with the ship’s ballast water management plan
  • The commencement and termination of the operation are recorded in the ship’s record of navigational activities as required by regulation 28

Conning position is a  place on the bridge with a commanding view and which is used by navigators when commanding, manoeuvring and controlling a ship.

Additional requirements of MSC 982


MSC Circ 982 contains guidelines on ergonomic criterial for bridge equipment and layout. These guidelines support Regulation 15 of SOLAS chapter V.

Click here to view MSC Circ 982 on the IMO website>

Some of these guidelines are summarised below.

Field of Vision around the Ship

There should be a field of vision around the vessel of 360° obtained by an observer moving within the confines of the wheelhouse.

Therefore, by moving around the bridge it should be possible to see all around the vessel.

Navigating and Manoeuvring Workstation

An old tug's rear bridge windows

Over an arc of not less than 225°, that is from right ahead to not less than 22.5°, abaft the beam on either side of the ship

Monitoring Workstation

At least over an arc from 90°  from 22.5 on the port bow, through forward, to 22.5° abaft the beam on starboard bow.

Bridge Wing

Should extend over an arc at least 225°, that is at least 45° on the opposite bow through right ahead and then from right ahead to right astern through 180° on the same side of the ship

Main Steering Position

From right ahead to at least 60° on each side of the ship.

Bridge wings should be provided out to the maximum beam of the ship. The view over the ship’s side should not be obstructed.


Lower Edge of the Front Window

The height of the lower edge of the front windows should allow a forward view over the bow for a person in a sitting position at the workstation for navigating and manoeuvring and the workstation for monitoring.

Removable Sunscreens

To ensure a clear view and to avoid reflections in bright sunshine, sunscreens with minimum colour distortion should be provided at all windows. Such screens should be readily removable and not permanently installed.

Glass Characteristics

Polarized and tinted windows should not be fitted.

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Guidelines for Navigational Bridge design

A ships wheel House and bridge wingWhat does MSC Circ 982 cover?

A handy guide

The last post covered the navigation bridge design principles as
required by SOLAS V; this post goes into more detail into how these principles are applied.

MSC Circ 982 contains guidelines on ergonomic criterial for bridge equipment and layyout. These guidelines support Regulation 15 of SOLAS chapter V. The
guidelines are designed to support watchkeeping by a user-centered design of the bridge layout and its equipment. This  post gives an overview of the scope of the guidelines, an overview that will assist in identifying what elements of a bridge are included.

What are the elements of navigation bridge design covered in MSC/Circ 982?

Click here for a copy of MSC Circ 982>

What are the navigation bridge workstations?

A workstation is combination of all job related items for certain tasks; this
includes devices equipment and furnitiure.

  • Navigating and manoeuvring– The main workstation for
  • Monitoring-The position from which equipment and
    environment can be observed
  • Manual steering-Helmsman’s position
  • Docking-Bridge wings
  • Planning and documentation-Postion used for route
    planning, fixing and documention
  • Saftey-Workstation for monitering safety systems
  • Communications– Workstation for operating GMDSS

Appendix 2 of MSC 982 conatains lists of equipment that should be at each

What are the factors regarding bridge layout?

These are the factors that determine where all the key items should be placed
on a bridge.

  • Sight– Field of vision, blind sectors,windows,
  • Arrangement-Bridge dimensions, view of the deck, window
    access, workstation position, communications
  • Accessibility and movement– clear routes, passageway

Some of these factors play an important role in mantaining a lookout (COLREG
Rule 5), and therefore will be looked at in a bit more detail in another post.

What are the elements covered in the work

These are factors that can influence the quality of bridge watchkeeping.

  • Climate-Temprature, humidity
  • Ventilation and Air-conditioning– Air disharges, air
  • Noise and Acoustics– levels of noise
  • Vibration-Levels of vibration
  • Illumination and Lighting-Level of lighting, dark
    adaptation, contrast, adjustability, glare, reflection
  • Occupational Safety-non-slip, sharp edges, hand rails,
    safety equipment marking

Bridge of a Fyffe ship

What does MSC cover regarding the workstation

Without such guidelines the layout of workstations can be chaotic, inconsistent
and difficult to use.

  • Consoles-Area, viewing angles, heights, leg room, chart
    table dimensions, chair design
  • Devices,Control and Display Integration– Logical
    arrangement, consistency, locations, high priority displays
  • Arrangement and Grouping of Controls-Pacement, location
    of primary controls, consitency, spacing
  • Display Arrangement-Field of view, viewing area
  • Labelling of Controls and Displays-Functional
    labelling, terminology
  • Lighting of Devices-Dimming,

What guidelines are contained regarding alarms?

  • Alarm Management– Alarm acknowledgement, fire and
    emergency alarms, power failure, alarm status, testing, presentation, modes
  • Visual Alarms-Discrimination, presentation, flash rate,
    night vision
  • Audible Alarms– Use of audible alarms, sound characteristic, sound
    pressure, frequency

What do the guidelines cover regarding Input devices?

  • Movement of Controls- Direction of control
  • Corresponding movements-Consistent with related
  • Return to Navigation monitering mode-Single operator
    action only to revert from planning mode
  • Minimal User Actions– Actions used to be simlple,
    minimum number of actions required
  • Feedback– Visual, auditory oe mechanical feedback
    provided to indicate imput
  • Operation of controls– Easy to identify and operate
  • Accessibility– Most important/frequently used functions
    easily visible and accessible
  • Operation of controls for Important functions- Require
    only single action
  • Assignment of controls of Important functions-Should be
    assigned to only one functionn
  • Accidental input-Designed to prevent accidental

Bridge wing of a ferry

What topics are covered regarding Information

  • General Display Requirements-Lack of ambiguity, use of
    digital displays, updating information, information duration, simplicity,
    uncluttered displays, important information, graphic display, scale,
    distance judgement
  • Arrangement of Visual Information-Screen organization,
    grouping of information, group demarcation, consistency
  • Visual Display Units (VDU)-Night vision, dat and night
    legibility, background colour, resolution, contrast, luminance, flicker,
    continuity, linearity
  • Coding and Highlighting-Highlighting selected data,
    flash coding for alarms, colour discrimination, colour difference, standard
  • Display Elements-Font, abberviations, units of
    measurement, icons, size of symbols and icons, highlighting, scaling
    intervals, scale expansion, grid displays

What does the guidelines on Interactive Control

  • General User Input Guidelines-Consitent procedures,
    standard procedures, consistent wording, unnessary information entry,
    available options
  • User Input Formats-Logical order, consistent menu
    design, minimal steps in meny selection, return to high level menus, return
    to general menu, menu titles, on/off items, form filling entry
  • System Operational Information-system status, mode,
    status of sensors, planned and actual data, position information sources,
    simulated operations
  • System Response-standard display location, familar
    wording, periodic feedback, warnings, error messages, on-line guidance
  • Prevention/Detection/Correction of Errors– Protection
    of data loss, segregating real and simulated data

Further Information Sources

Some of the factors mentioned in the post have significance to officer of the watches, and those factors I will explore in the next posting.

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