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.”
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.
The 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.
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
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
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.
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.
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.
Polarized and tinted windows should not be fitted.
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