Tag Archives: Navigational equipment

Where should a vessel’s masthead lights be placed?

Power Driven vessel end on

Navsregs>COLREGS>Masthead light position

More delving into the detail of navigation lights, this time its the positioning of masthead lights.

The vertical positioning of Masthead lights

What part of the COLREGs covers the vertical positioning of Masthead lights?

Annex 1 part 2.

At what height should masthead lights be carried?

On a power-driven vessel of 20 meters or more in length:

The forward masthead light, or if only one masthead light is carried, then that light is:

  • At a height above the hull of not less than 6 meters

and

  •  If the breadth of the vessel exceeds 6 meters, then at a height above the hull not less than such breadth, so however that the light need not be placed at a greater height above the hull than 12 meters

The masthead light of a power-driven vessel of 12 meters but less than 20 meters in length:

  •  Shall be placed at a height above the gunwale of not less than 2.5 meters.

The masthead light of a power-driven vessel of less than 12 meters in length:

  • These may carry the uppermost light at a height of less than 2.5 meters above the gunwale.
  • When however a masthead light is carried in addition to side-lights and a sternlight or the all-round light prescribed in Rule 23(c)(i) is carried in addition to sidelights, then such masthead light or all-round light shall be carried at least 1 meter higher than the

The masthead light or lights prescribed in shall be so placed as to be above and clear of all other lights and obstructions except for Not Under Command Lights and Restricted in Manoeuvrability.

MastClutter

What is the separation of two masthead lights?

The after one shall be at least 4.5 meters vertically higher than the forward one.

The vertical separation of masthead lights of power-driven vessels shall be such that in all normal conditions of trim the after light will be seen over and separate from the forward light at a distance of 1000 meters from the stem when viewed from sea level.

Horizontal positioning of Masthead lights

What part of the COREGS covers the horizontal positioning of Navigation lights?

Annex 1 3 Horizontal positioning and spacing of lights

the horizontal distance between them shall not be less than one half of the length of the vessel but need not be more than 100 meters. The forward light shall be placed not more than one quarter of the length of the vessel from the stem.

A quick summary of the Masthead Light distances

LightsMastheadpositionSmall


Shapes and a Bit More

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The range of ship’s navigation lights

Navsregs>COLREGS>Navigation Light Range

​This post starts of with the simple facts of COLREG 22 and then delves deeper and deeper into definitions; deep into the world of lux, lumens and candelas.

Sunset in the Med

The range of Navigation lights

What Rule states the visibility of Navigation lights?

Rule 22-visibility of lights

Note: This Rule states that navigation lights shall have an intensity as specified in Section 8 of Annex I to the COLREGS.

What is the range of Navigation lights in a vessel of 50 meters or more in length?

  • Masthead light- 6 miles
  • Sidelight-3 miles
  • Sternlight-3 miles
  • Towing light-3 miles
  • A white, red, green or yellow all-round light-3 miles

What is the range of Navigation lights in a vessel of 12 meters or more in length but less than 50 meters in length?

  • Masthead light, 5 miles; except that where the length of the vessel is less than 20 meters, 3 miles
  • Sidelight- 2 miles
  • Sternlight-2 miles;
  • Towing light-2 miles;
  •  White, red, green or yellow all-round light-2 miles

What is the range of Navigation lights in a vessel of less than 12 meters in length?

  • Masthead light- 2 miles
  • Sidelight- 1 mile
  • A sternlight- 2 miles
  • Towing light-2 miles
  • White, red, green or yellow all-round light- 2 miles

What is the range of Navigation lights of an inconspicuous, partly submerged vessel or object being towed?

White all-round light- 3 miles.

Waiting for the amplitude

The intensity of Navigation lights

The intensity required to achieve the minimum range is derived from a formula given in Section 8 of Annex I to the Colregs.

The intensity formula

1=3.43 × 1 06×T × D2 × K-D

What do the parts of the Navigation light intensity formula mean?

I is luminous intensity in candelas under service conditions

The candela is the SI unit of luminous intensity.  It is the luminous power per unit solid angle emitted by a point light source in a particular direction.

Or to be more accurate, it  is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540×1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.

The steradian is a square radian, and is the SI unit of solid angle.

T is threshold factor 2 × 10-7 lux

The lux is the SI unit of illuminance and luminous emittance, measuring luminous flux per unit area.It is equal to one lumen per square metre. It is used as a measure of the intensity, as perceived by the human eye.

The lumen is  the SI unit of luminous flux, a measure of the total quantity of visible light emitted by a source.

D is range of visibility (luminous range) of the light in nautical miles

The luminous range is the maximum distance at which a light can be seen, as determined by the luminous intensity of the light, the atmospheric transmission factor and the threshold of illuminance on the eye of the observer.

Ship's at anchor off Gibraltar

 K is atmospheric transmissivity.

Atmospheric transmissivity is he ratio of the directly transmitted flux incident on a surface after passing through unit thickness of the atmosphere to the flux that would be incident on the same surface if the flux had passed through a vacuum.

The value of K shall be 0.8, corresponding to a meteorological visibility of approximately 13 nautical miles.


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Navigation lights defined

Navsregs>COLREGS>Navigation Lights defined

Down another level, down past the Rule list, down through the power-driven vessel rule, down to some definitions.

A quick guide to Navigation light definitions

Where are the definitions for Navigation lights?

Section C  of the COLREGS, Rule 21.

Here are those definitions condensed down to some easy to remember facts.

What is a masthead light?A Masthead Light

  •  White light
  •  Placed over the fore and aft centerline of the vessel showing an unbroken light over an arc of the horizon of 225 degrees
  • So fixed as to show the light from right ahead to 22.5 degrees abaft the beam on either side of the vessel

What are Sidelights?

  • Green light on the starboard side and a red light on the port side Port Sidelight
  • Each showing an unbroken light over an arc of the horizon of 112.5 degrees
  • So fixed as to show the light from right ahead to 22.5 degrees abaft the beam on its respective side.

In a vessel of less than 20 meters in length the sidelights may be combined in one lantern carried on the fore and aft center-line of the vessel.

When did the Red and Green sidelights come into use?

In 1848 the UK issued  regulations requiring steam vessels to display red and green sidelights as well as a white masthead light. This was a follow on from an act of 1846 that became the basis of the current IMO COLREGS.

 

What is a Sternlight?Sternlight on a bunker tanker

  • White light
  • Placed as nearly as practicable at the stern
  • Showing an unbroken light over an arc of the horizon of 135 degrees
  •  So fixed as to show the light 67.5 degrees from right aft on each side of the vessel

What is a Towing light?

  • Yellow light
  • Same characteristics as the sternlight

 

What is an all-round light?

  •  A light Showing an unbroken light over an arc of the horizon of 360All-round lights degrees

What is a Flashing light?

  • A light flashing at regular intervals at a frequency of 120 flashes or more per minute

Why are the arcs of navigation not given in rounded numbers of degrees?

The arcs of navigation lights are based on the traditional mariners compass. In this each ‘point’ is 1/32 of a circle, which is 11.25 degrees.  The change in arch between Masthead lights/Sidelights and the sternlight occures at 2 points abaft the beam, that is 22.5 degrees.

The Navigation Light Definitions and the Rest of The COLREGS

Two vessel situations are defined within the Rules by the aspects of their navigation lights; a crossing situation is implied by being neither of these.

Overtaking-Rule 13

A vessel overtaking when coming up with another vessel from a direction Power Driven Vessel from Asternmore than 22.5 degrees abaft her beam, that is, in such a position that at night she would be able to see only the sternlight of that vessel but neither of her sidelights.

Head on (Power-driven vessels)-Rule 14Power Driven vessel end on

A head on situation exists when a vessel sees the other ahead or nearly ahead and by night she could see the masthead lights of the other in a line or nearly in a line and/or both sidelights, and by day she observes the corresponding aspect of the other vessel.

 


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COLREGS and Navigation lights

Navsregs>COLREGS>COLREGS and Navigation lights

It is time for a change of tack across on the Navregs blog, to leave the SOLAS V  posts to one side for a bit and delve down into a subject area not covered for a while, the COLREGS. This time it is lights.

The posts will start at the generic level, and then descend into more and more detail, and see where it finally reaches the bottom of the regulatory pile.

Power Driven Vessel Lights

Which Rules cover navigation lights?

Here is a list the COLREG rules defining the lights vessels must show. Part C of the Rules is the section covering navigation lights. As the posts build in this series, so this list will have links added to form a useful index.

  • Rule 20 Application
  • Rule 22 Visibility of lights
  • Rule 23 Power driven vessels underway
  • Rule 24 Towing and Pushing
  • Rule 25 Sailing Vessels Underway and vessels Under oars
  • Rule 26 Fishing Vessels
  • Regulation 27 Vessels Not Under Command or Restricted in Their Ability To Manoeuvre
  • Rule 28 Vessels constrained by their draft
  • Rule 29 Pilot Vessels
  • Rule 30 Anchored Vessels and Vessels aroun
  • Rule 31 Seaplanes

The Annexes

Much of the technical specifications of navigation lights is contained within ANNEX I.

  • ANNEX I-Positioning and technical details of lights and shapes
  • ANNEX II-Additional Signals for fishing vessels fishing in close proximity

What is contained within the Navigation light Rules?A Masthead Light

And here is a list of the contents of those Rules, and some additional rules from the rest of the COLREGS with navlight related topics.

Rule 1 Application

  • (C) Additional lights and shapes
  • (E) Vessels of special constuction or purpose

Part C lights and shapes

Rule 20 Application

  •  (a) Requirement to comply with  in all weathers.
  •  (b) Requirement to comply with at night.
  • (c) When to require with  part during the day
  •  (e) The lights  shall comply with the provisions of Annex I

Rule  21 DefinitionsPort Sidelight

  • (a) Masthead light
  • (b) Sidelights
  • (c) Sternlight
  • (d) Towing  light
  • (e) All -Round light
  • (f) Flashing light

Rule 22 Visibility of lights

  • (a) Vessels of 50 metres or more in length
  • (b) Vessels  of 12 metres or more in length but less than 50 metres in length
  • (c) Vessels of less than 12 metres in length
  • (d) Lights on inconspicuous towed vessels or objects

Rule 23 Power driven vessels underway

  • (a) What a power driven Vessel Underway must exhibit
  • (b) What an air cushion vessel should exhibit
  • (c) What a power driven vessel of less than 12 metres in length should exhibit

Rule 24 Towing and Pushing

  • (a) What a power driven vessel when towing must exhibitAll-round lights
  • (b) What a vessel pushing ahead as a composite unit shall exhibit
  • (c) What a vessel pushing ahead of towing alongside shall exhibit
  • (d) Requirement to comply with Rule 23(a}(ii) in addition
  • (e) What a vessel or object being towed should exhibit
  • (f) What a group of vessels being towed should exhibit
  • (g) What inconspicuous or partly submerged objects or vessels should exhibit.
  • (h) When a towed vessel cannot exhibit these lights
  • (i) What can be displayed by vessels towing a vessel in distress or need of assistance

Rule 25 Sailing Vessels Underway and vessels Under oars

  • (a) What a sailing vessel underway should exhibit
  • (b) What a sailing vessel of less than 20 metres in length
  • (c) Additional lights that may be shown by sailing vessels
  • (d) What sailing vessels of less than 7 metres in length and vessels under oars shall show

Rule 26 Fishing Vessels

  • (a) Requirement that a vessel engaged in fishing should comply with only this RuleFishing Vessel lights
  • (b) What a vessel engaged in trawling shall exhibit
  • (c) What a vessel engaged in fishing other then trawling shall exhibit
  • (d) When the additional signals in Annex II can be used
  • (e) What a vessel not engaged in fishing shall exhibit

Regulation 27 Vessels Not Under Command or Restricted in Their Ability To Manoeuvre

  • (a) What a vessel not under command shal exhibit
  • (b) What a vessel restricted in her ability to manoeuvre shall exhibit
  • (c) What a towing vessel when restricted in her ability to manoeuvre should exhibit
  • (d) What a vessel engaged in dredging or underwater operations shall exhibit
  • (e) What a small vessel engaged in diving may exhibit
  • (f) What a vessel engaged in mine clearance shall exhibit
  • (g) The requirements for vessels less than 12 metres in length
  • (h) These lights do not mean distress

Rule 28 Vessels constrained by their draft

Rule 29 Pilot Vessels

  • (a) What a pilot vessel engaged in pilot duty shall exhibit
  • (b) What a pilot vessel not engaged in pilot duty shall exhibit

Rule 30 Anchored Vessels and Vessels around

  • (a) What a vessel at anchor shall exhibit
  • (b) What a vessel of less than 50 metres in length may exhibit when at anchor
  • (c) What a vessel of over a 100 metres in length shall exhibit in addition

Rule 31 Seaplanes

What lights a seaplane shall exhibit

Rule 36 Signals to attract Attention

Rule 38 Exemptions

The following expemtions are still in force:

  • The repositioning of lights as a result of conversion from Imperial to metric units and rounding off measurement figures
  • The repositioning of masthead lights on vessels of less than 150 meters in length, resulting from theprescriptions of Section 3(a) of Annex I
  •  The repositioning of all-round lights resulting from the prescription of Section 9(b) of Annex I

The Annexes

Navigation lights from the bulk of the  Annexes of the COLREGS. ANNEX I contains all the detail of what, where, and how the lights should be fitted.

ANNEX I

POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES

  • 1. Definition
  • 2. Vertical positioning and spacing of lights
  • 3. Horizontal positioning and spacing of lights
  • 4. Details of location of direction-indicating lights for fishing vessels, dredgers
  • and vessels engaged in underwater operations
  • 5. Screens for sidelights
  • 7. Colour specification of lights
  • 8. Intensity of lights
  • 9. Horizontal sectors
  • 10. Vertical sectors
  • 11. Intensity of non-electric lights
  • 12. Manoeuvring light
  • 13. High Speed Craft
  • 14. Approval

ANNEX II

Additional Signals for fishing vessels fishing in close proximity

  • 1. General
  • 2. Signals for trawlers
  • 3. Signals for purse seiners

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The requirement to keep nautical charts and publications up to date

Adequate and up to date, the two important features that SOLAS V demands of charts and publications. This post looks at that requirement in more detail, and also introduces a new book in the ‘Really Handy Guide’ range of Kindle Revision aids.

Bridge wings and MoonSOLAS V Regulation 27 – Nautical Charts and Nautical Publications

What are the requirements for the carriage of nautical charts and publications according to SOLAS V?

Nautical charts and nautical publications necessary for the intended voyage, shall be:

  • Adequate
  • Up to date

Note: Flag states can have some flexibility in defining which ships have to comply with this Regulation. In the case of UK flagged ships it applies to all ships except for pleasure vessels of less than 150 gt.

What type of publications does this refer to?

Sailing directions, lists of lights, notices to mariners, tide tables and all other nautical publications.

A definition from the regulations

 “Nautical chart” or “nautical publication” is a special-purpose map or book, or a specially compiled database from which such a map or book is derived, that is issued officially by or on the authority of a Government, authorized Hydrographic Office or other relevant government institution and is designed to meet the requirements of marine navigation.” Regulation 2

What SOLAS Regulation states the carriage requirements for charts and nautical publications?

SOLAS V Regulation 19.

Where can I find some useful guidance on the carriage and use of Nautical Charts and Publications?

In Annex 3 to the UK guidance to SOLAS V.

Guidance on the use of Electronic Charts is contained in ANNEX 14.
Bridge window

UK guidance on the updating of electronic charts

Within the  UK MCA SOLAS V guidance is a section on the updating of electronic charts, here is a summary of the key points.

  • Updates available in port should be applied before passage planning commences and before leaving port.
  •  If updates are received at sea they should be applied as soon as possible.
  • Any changes relevant to the execution of the passage plan should be noted on the passage plan
  •  Updates need to be applied to both primary and secondary systems
  •  Records should be kept of when updates are received and applied
  •  During passage planning it should be checked that any licences concerning the use of the software and its updates will remain valid for a period in excess of the expected worst-case voyage duration. If this is not the case corrective action needs to be taken.

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Electromagnetic Compatibility and Navigational Equipment

Navsregs>SOLAS>SOLAS V>Electromagnetic Compatibility

A Handy Guide to SOLAS V Regulation 17 – Electromagnetic Compatibility

Polarcus Alima's bridge

After that brief pause to look at changes to MARPOL this blog now returns to exploring the regulations of SOLAS Chapter V.

Click here to read Regulation 17 on the UK MCA website>

What vessels must comply with Regulation 17?

Ships constructed on or after 1 July 2002

What does this regulation require regarding equipment testing of bridge equipment?

That all electrical and electronic equipment on the bridge or in the vicinity of the bridge is tested for electromagnetic compatibility (EMC).

What resolution gives the requirements for Electromagnetic compatibility with navigational equipment?

A.813(19)

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What should the installation of electrical and electronic equipment avoid with regards to bridge navigation equipment?

Electromagnetic interference affecting the proper function of navigational systems and equipment. Portable electrical and electronic equipment shall not be operated on the bridge if it may affect the proper function of navigational systems and equipment.

What must masters ensure regarding portable electronic equipment being used on a ship’s bridge?

That no portable electrical or electronic equipment that might cause interference is used on or near the bridge. This includes not only ship’s equipment but also personal items such as  portable radios, hi-fi equipment and lap top computers. Non-transmitting equipment displaying the European “CE” mark will probably not cause interference.

Mobile phones, while not likely to cause electromagnetic interference, prove to be an increasing distraction to safe navigation. MGN (M&F) 299 – Interference with Safe Navigation through inappropriate use of Mobile Phones is to be complied with.

IECFor Electromagnetic Compatibility standards refer to IEC 60945

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