Cdr John Aigner, Royal Navy, United Kingdom: A user-focused approach to the provision of Aids to...

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COST CUTTING, EFFICIENT AND SAFE OPERATIONS: A USER-FOCUSED APPROACH

TO THE PROVISION OF AIDS TO MARINE NAVIGATION (ATON) IN CONFINED WATERS

John Ainger

Ian Burgess

IHMA 2012

Cork 16.05.12

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COST CUTTING, EFFICIENT AND SAFE OPERATIONS: A USER-FOCUSED APPROACH

TO THE PROVISION OF AIDS TO MARINE NAVIGATION (ATON) IN CONFINED WATERS

John Ainger

Ian Burgess

IHMA 2012

Cork 16.05.12

This presentation is animated; select “slideshow” icon, to click on, as required

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Background I

Advances in electronic technology, at sea since 1980s

Mandatory carriage of GNSS, Radar, AIS, & ECDIS in SOLAS ships

• Improvements in the accuracy/safety of marine navigation

• Widespread introduction of GNSS has challenged AtoN Providers to

review AtoN requirements

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Background II

Developments in visual AtoN technology

Offer higher capability, longer maintenance intervals and lower

through-life costs

• Buoys constructed with hydrophobic filling and from self-coloured,

UV-protected polyethylene

• LED light sources and self- contained solar powered LED

arrangements

• Remote Monitoring & Control capability

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Introduction I

The Paper

Considers the impact of mandatory carriage requirements on the role

of AtoN in general

Examines the requirement for AtoN more specifically

• Using a user-focused approach

• Relating AtoN visibility to a “must-see” range

• Taking account of geography and vessel/craft speed

• Translating these requirements into equipment specifications that

reflect the latest developments in AtoN technology

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Introduction II

Role of AtoN

In open waters, GNSS is available for a primary navigational role:

• Accurate and easy to use for position fixing;

• However its vulnerability in coastal and confined waters is widely

accepted

In coastal waters, SOLAS Chapter V, Regulation 13 makes Coastal States

responsible for providing AtoN

• AtoN, therefore, are available, for a secondary role in coastal waters;

• As is the use of ship-borne radar

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Introduction III/Key Words

In confined waters, however, Visual AtoN retain a

primary role in safe navigation with GNSS and ship-

borne radar in a secondary, back-up role

Key Words/Phrases

Day Time Visibility DTV

Minimum Effective Light Range MER

Geographical Light Range GLR

Nominal Light Range NLR

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Key Words/Phrases II

DTV and MER requirements are subjective

judgements best made with local knowledge

NLR is a means of using MER requirements to develop a

specifiable light range

Specifying Focal Plane Height when the required GLR is <

5 nm is irrelevant

Estimates of DTV and MER requirements are offered for

consideration in the following situations:

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Key Words/Phrases III

In the Approaches to confined waters

Fairway Buoys

Channel Entrance Buoys

Harbour Entrance Lateral Marks

Within Ports and Harbours

Channel Buoys

Harbour Entrance Lateral Marks

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Key Words IV/AtoN Requirements

Points of Navigational significance

Other AtoN requirements

AtoN Requirements – Factors affecting AtoN Size

(Other than local environmental factors that do so eventually)

Must-See Ranges

DTV by day

MER by night

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Factors affecting AtoN Size - DTV

DTV varies with perceived cross-sectional area, typically

Range (nm) 1 1.5 2.4

Cross-sectional area (m2) 1.28 2.65 6.9

Buoy Size (m) – Hull diameter

1.5 2.2 2.4

Focal Plane Height

1.9 3.0 4.0

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DTV II

DTV (nm) 1.0 nm 1.5 nm 2.4 nm

Cross-Sectional Area (m²) 1.28 2.65 6.90

Buoy Size Diameter (hull) 1.5 2.2 2.5

Focal Plane Height (FPH) 1.9 3.0 4.0

Illustrated DTV/Buoy size summary

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GLR I

MER (Required GLR) of an AtoN is

Limited by:

Curvature of the earth

Elevation of the light

Observer’s height of eye

Refraction of the atmosphere

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GLR II

Height of Eye of Observer (m)

1 2 3 4

AtoN Elevation/FPH (m)

Visible Range (nm)

0 2.0 2.9 3.5 4.1

1 4.1 4.9 5.5 6.1

2 4.9 5.7 6.4 6.9

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GLR III

Height of Eye of Observer (m)

2 3 4 5

AtoN Elevation/FPH (m)

Visible Range (nm)

1 4.9 5.5 6.1 6.6

2 5.7 6.4 6.9 7.4

1 – 2 m FPH provides GLR >5 nm, thus

AtoN light on buoy with 1 nm DTV specified, 1.9 m FPH and

relevant intensity has > 5 nm GLR, so if

Req’d MER/GLR is < 5 nm, why specify light FPH/elevation?

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NLR

Is light range when

Meteorological visibility = 10nm, i.e

Transmissivity Factor, T = 0.74

Background Lighting Factor BLF = 0

Can be

Converted from “must-see” MER by multiplication

with BLF

Used in Suppliers’ literature and by providers in

enquiries or tenders

NLR

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DTV & MER Requirements I

Buoys:

1 - 2 nm DTV and MER

Shore Lights:

5 nm MER, except

Up to 16 nm NLR, where National Authorities consider

geography and vessel traffic concentrations warrant this

AtoN in Secondary Role in Coastal Waters

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DTV & MER Requirements II

With DTV/MER = 1.5 – 2 nm, FWB

light visible for:

15 - 20 minutes @ up to 6 knots

7 – 10 minutes @ 12 knots

4 minutes @ 30 knots (HSC)

Approaches to Confined Waters - Fairway Buoy (FWB)

Considering

GNSS with WP & radar with parallel index available;

Buoy may be fitted with racon and/or AIS capability;

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DTV & MER Requirements III

With DTV/MER = 1.5 – 2 nm, Buoy

lights visible:

15 - 20 minutes @ up to 6 knots

7 – 10 minutes @ 12 knots

4 minutes @ 30 knots (HSC)

Approaches to confined waters – Channel Entrance Buoys (no

FWB)

Similarly,

GNSS with WP & radar with parallel index available;

One buoy may be fitted with racon and/or AIS capability;

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DTV & MER Requirements IV

With MER = 2 nm, Entrance lights visible 15 - 20 minutes @

up to 6 knots; 7 – 10 minutes @ 12 knots; 4 minutes @ 30 kn.

Approaches to confined waters – Harbour Entrance Marks (no

FWB or buoyed channel)

Similarly, GNSS with WP & radar with parallel index available;

Harbour entrance conspicuous on radar

MER = 2 nm

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DTV & MER Requirements V

Approaches to confined waters – Leading Lines

Required to counter cross track wind and current;

Marked by two lit marks or by a single PDL

IALA Guideline 1023 provides spreadsheet calculation, to

Optimise their design;

Select light intensities, so both lights look equally bright

GNSS with WP & radar plus parallel index similarly available;

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DTV & A/MER Requirements VI

FEUS

Centreline

NEUS

C M R

W

Sensitivity determined by CTF at FEUS always >10%;

10-15% = Excellent; 15-20% = VG; 20=30% = G; 30-50% = Fair

Min. Intensity @ T=.74 at FEUS (found via Min. Vis.) x BLF x 10

= Rec. Intensity

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DTV & A/MER Requirements VII

Within P & H – Channel Buoys;

By day, two Lateral buoy pairs should be visible at the same

time, if buoy DTV = 1 nm & buoy longitudinal spacing = about

750 m

750 m spacing

DTV = 1 nm

750 m spacing

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DTV & MER Requirements VIII

By night, the lights of three Lateral buoy pairs with the same

DTV & spacing should be visible at the same time, if the MER

of each is 1.25 nm

750 m spacing

MER = 1.25 nm

750 m spacing

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DTV & MER Requirements IX

Harbour Entrance Lateral Marks, inshore of a buoyed channel

Typically, DTV = 1 nm & MER = 1.25 nm

Spacing = 750 m

MER = 1.25 nm

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DTV & MER Requirements X

Points of Navigational Significance

Typically, turning points that can be marked by buoys or

beacons with Q flash character lights with MER = 1.25 nm

QG

QR

750 m spacing 750 m spacing

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DTV & MER Requirements XI

Special

Other Marking Requirements unlikely to require DTV or MER

> 1 nm include:

Isolated DangerSafe water Cardinal

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Background Lighting I

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Background Lighting II

Background Lighting Factor (BLF) – a light intensity multiplier

that counters the effect of ambient background lighting

BLF = 0 – 10

(2 nm requires 5 - 50 cd)

BLF = 40 – 50

(2 nm requires 200 – 250 cd)

BLF = > 100

(2 nm requires > 500 cd)

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Background Lighting III

Ambient levels can vary with observer’s location; for example

Lower in the approaches to a buoyed channel;

Higher within a well-lit harbour

Specific Street or Commercial Lighting

Can reduce effective intensity of AtoN lights, significantly,

depending on the Observer’s location and height of eye

May affect SON critically in zones of navigational significance

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Background Lighting IV

Increasing light intensity is unlikely to solve the problem for

HSCs

HSC Bridge HE

Specific BLSOLAS bridge HEOr put another way

HSC Bridge HE

Specific BLSOLAS bridge HE

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HSC Bridge HE

Specific BLSOLAS bridge HE

Counter-measures include:

Raising or lowering light elevation

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Using distinctive

flash characters &

synchronisation

Installing a

distinctive light

system

“Never rely solely

on one mode of

Navigation”

May also apply to the use of a Visual AtoN, especially one

that has AIS capability that identifies it on ECDIS

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Meeting AtoN Requirements I

Technological Advances offer reduced through-life costs

Floating AtoN - use of polyethylene

UV-stabilised colouring

20-year service life

Hydrophobic filling

Damage mostly cosmetic – can

be repaired in situ

High buoyancy-to-weight ratio

Less expensive to transport;

handle; deploy & recover

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Meeting AtoN Requirements II

SS fittings & modern AtoN equipment

Increase maintenance intervals

governed by wear of moorings

Oversized moorings can increase

Maintenance intervals to 4 – 5 years

Through-life costs 35–50 % less,

compared with steel buoys

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Meeting AtoN Requirements III

AtoN Light Equipment – Use of LED Light Sources

Long maintenance intervals

Increased intensity/input Power ratio

SC Solar Powered AtoN Lights

6.5W for 5-6 M NLR

10W lamps in old Buoy lights: 3-4 M

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Meeting AtoN Requirements IV

Vertical Divergence up to 20o

Used in Rotating Beacons

Easy drop-in arrangement for

retrofit/replacement

Ranges up to 16 M in non-rotating Beacons

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Meeting AtoN Requirements V

Microprocessor-based electronic control and enhancing

equipment

Up to 256 pre-programmed flash character timing options

GNSS timing circuitry to synchronise lights

BITE and exception reporting monitoring inputs

Warn of failures before they occur

Mesh & Satellite Remote Monitoring (SRM) software

Provide reliable monitoring of AtoN

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Meeting AtoN Requirements VI

Mesh Software finds alternative radio paths

Direct link

failure

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Meeting AtoN Requirements VII

AIS circuitry with low power consumption

can be added to AtoN to:

Identify them, additionally, on ECDIS or

Radar displays

Enable AIS equipped vessels to monitor

The operating health of an AtoN

If a floating AtoN is “out of position”

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Meeting AtoN Requirements VIII

Frequency Agile (FA) Racons with

Low power consumption

Ingress protection (10 m immersion)

Effective Side-lobe Suppression

Enhance AtoN

identification

on radar

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Meeting AtoN Requirements IX

Radar Target Enhancers (RTE) with

Low power consumption

input power protection from damage by 25

KW radars

Enhance radar detection range, so that

AtoN buoys, so equipped, are detected by craft with 3 or

10 KW radars and small displays, in time to avoid collision

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Conclusions

Whilst Visual AtoN have a secondary role in coastal water

navigation, they retain a primary role in confined waters

Advances in AtoN technology

Support a user-focused approach, in which

DTV & MER specs make buoy diam. & FPH irrelevant

Proposed Must-see” levels of visibility are subjective &

general for providers to consider in local contexts

Offer ample scope for improving AtoN capability, integrity &

maintenance intervals, so reducing through-life costs

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Recommendations

That Providers of AtoN in Ports & Harbours consider

The user-focused approach, used in this paper, to identify

buoy sizes and numbers and AtoN nominal light range, to

suit local circumstances

The specifications of essential and optional-extra

equipment at Appendix

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Contacts

John Ainger: [email protected]

Ian Burgess: [email protected]

mailto:[email protected]

mailto:[email protected]

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