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1 INTRODUCTION

Navigation safety is essential to ensure the safety of

life and assets at sea, and to protect the marine

environment from any source of pollution. One way

to ensure the navigational safety is to mark the area

which has been identified as being safe for navigation

using marine Aids to Navigation (AtoN). AtoN is a

device, system, or service, which is external to the

vessels, and is designed and operated to enhance the

safe and efficient navigation of individual vessels

and/or vessel traffic [1]. The usage of AtoN is

regulated by the national maritime safety agency

following the guidelines developed by the

International Association of Marine Aids to

Navigation and Lighthouse Authorities (IALA). AtoN

is categorised into visual, audible, and electronic

categories. The typical AtoN used to mark navigation

channels or fairways leading to a port are navigation

buoys and leading line. Navigation buoys are used to

mark the edge of either side of the navigation channel,

while the leading line is used to mark the centre of the

channel. The leading line is marked by leading marks

during daytime and leading lights during night time.

A combination of navigation buoys and leading line

are used to mark the navigation channel. Leading

marks and lights are categorized under visual AtoN.

Leading marks are navigational marks used as

components for a leading-line or range. Leading line

is defined as “a straight line used for navigation

produced by the alignment of marks (leading marks)

or lights (leading lights) or by the use of radio

transmitter” [1], [2] This study highlights the

daymarks and different shapes of these daymarks to

A Study to Determine the Most Effective Daymark

Shape for a Leading Line

A.F. Ahmad Fuad

, D.A.A. Adlan

, A.S. Kamis

& M.S. Ahmad

University Malaysia Terengganu, Kuala Nerus, Terengganu, Malaysia

2 Akademi Laut Malaysia, Masjid Tanah, Melaka, Malaysia

ABSTRACT: The use of daymark shapes for leading lines include its visual shape and symbol, to aid sailors

who need to navigate safely through a marked narrow channel. The shapes which are currently used are

rectangles, diamonds, and triangles. However, there is not much information on which shape is the most

effective for navigational referencing. Therefore, the main objective of this research is to determine the most

effective shape for a leading line daymark. The Kemaman Port was used as an area of interest to model the

three-dimensional simulation. The size and height of the leading line daymark was calculated based on the

dimensions of the navigational channel obtained from the Kemaman Port navigation chart. The simulation for

different shapes of the leading mark in the same area was developed using a three-dimensional software.

Experts were engaged to evaluate the effectiveness of each daymark shape across the maximum and minimum

distances during the simulation run. Results showed that the diamond shape daymark was relatively better

identified and used as reference, compared to other shapes in the same range due to its relatively larger surface

area. Therefore, the study objective was achieved, and the results can be used to improve marine navigation

safety.

http://www.transnav.eu

the International Journal

on Marine Navigation

and Safety of Sea Transportation

Volume 16

Number 3

September 2022

DOI: 10.12716/1001.16.03.11

498

mark the navigation channels, in order to maintain

safety of navigational. There has not been much

studies done on the effectiveness of the different

shapes of daymark board. Therefore, in order to

address this issue, the main objective of this study is

to determine the most effective shape of leading mark

board.

2 METHODOLOGY

To achieve the study objective, the research

methodology has been developed. The overall

research activities in shown by a flow chart in Figure

1. The detail explanation for each step is given in the

following sentences.

Figure 1. Overall research activities

Step 1 was to obtain information related to the

shape of the daymark board of the leading mark

through literature reviews and interviews. The

information was obtained using the search engine in

the IALA website https://www.iala-

aism.org/guidance-publications/search-in-

publications/ [3]. The search engine was used for

searching for the relevant information on the content

of a repository based on the current IALA standards,

recommendations, guidelines, model courses, and

manuals, using the key words. In addition to

literature reviews, online interviews were conducted

with Marine Officer of the Marine Department of

Malaysia in which oversees the operation and

maintenance of the AtoN in East Coast Peninsular

Malaysia. This was conducted using the WhatsApp

application which enabled the sharing of documents

and photos on leading marks or lights [4].

Step 2 was to develop simulations based on the

shape of the leading mark board obtained in Step 1.

The simulation was developed using the SketchUp

Software [5]. The different types of daymark boards

were developed, and the size of the board was

determined using Eq. 1, Eq.2 and Eq.3 from the IALA.

650

Hh=+

(1)

( )

KD H h

−

(2)

( )

D H h

−

(3)

where:

H: Height of rear tower

h: Height of Front Tower

D: Distance we required/ Focus Distance

W: Width of Channel

R: Distance between two towers

K: Index Sensitivity

Step 3 was to run the simulations and review it

with experts. The experts were maritime lecturers in

Universiti Malaysia Terengganu with a minimum

unlimited class 3 certificates of competency. Based on

the observations, the experts ranked the shapes.

3 RESULTS AND DISCUSSION

The first objective was obtained through literature

reviews and interviews. Based on IALA (2001, 2014,

2016), there were four types of constructions for the

daymark, namely flat, solid, lattice, and crossed plate

constructions. Through the literature review, the flat

construction was the most preferred design for the

daymark for leading lights compare to solids, lattices

and crossed constructions [6]. The reason was that the

flat surface would project the same colour and

brightness.

To achieve the second objective, the Kemaman

Port was used as model for the study area. The reason

for the selection of the Kemaman port was that it was

equipped with leading lights and was much closer to

the researcher’s residence, which made the survey

easier. Information on the leading light was obtained

from the online electronic chart by Navionics which

was sourced from the Malaysian charts, as shown in

Figure 2. The first pair of leading lights that marked

the fairway from the sea was the Tg. Berhala No. 8

and Tg. Berhala No.10. The second pair that marked

the channel into the port’s turning basin was the Tg.

Berhala No. 7 and Tg. Berhala No. 9, and was used as

a model for this study.

Figure 2. Kemaman Port Chart (Source: Navionics, 2022)

Tg. Berhala No. 7 is the front leading light and

mark. The light’s focal plane was 21 m with a quick-

flashing green light. Approximately 18 m of a square

skeletal tower carrying a triangular daymark painted

in white with a red vertical stripe was seen as ideal

[9]. Tg. Berhala No. 9 is a rear leading light and mark.

The light’s focal plane was 27 m with a green light,

499

which was on for 2 seconds and off for 2 seconds.

Approximately 20 m of the square skeletal tower

carrying a triangular daymark painted in white with a

red vertical stripe was seen as ideal. The distance

between the rear and front leading towers were 210 m

[9].

Instead of using the real information as that used

for the Kemaman Port to develop the area’s

simulation model, this study calculated the size and

height of the daymark board based on the information

obtained from the online chart, namely the width of

the navigation channel and distance of the daymarks

and lights. The chosen height of the observer’s eye on

the ship was 15 m. Therefore, the maximum height of

the daymark at the front tower was set to 15 m. The

calculation of both the leading line towers were done

using Eq. 1, Eq. 2, and Eq. 3. Results of the calculation

are shown in Table 1.

Table 1. Result of calculation

_______________________________________________

Item Information

_______________________________________________

Height of rear tower 18.93 m

Height of front Tower 15 m

Distance we required/ Focus Distance 2560 m/ 1.4 nm

Width of channel 808 m

Distance between two towers 450 m

Index Sensitivity 1.7

_______________________________________________

IALA has derived the dimensions of the dayboard

of the leading line which corresponds with the

operational range as shown in Table 2. The distance of

the channel mark was 1.4 nm. The operational range

of 2 nm was chosen for the dayboard size of the front

tower and 2.2nm was for the rear tower. The drawing

of the towers and daymarks are shown in Figure 3.

Table 2. Dayboard size and range (Source: IALA (2016)

_______________________________________________

Dayboard Size Operational Viewing Viewing

L x W meter Range NM angle for angle for

length L width W (L/2)

_______________________________________________

1.6 x 0.8 1 2.9’ 1.5’

2.1 x 1.05 2 2.0’ 1.0’

3.1 x 1.55 3 1.9’ 1.0’

4.2 x 2.1 4 2.0’ 1.0’

_______________________________________________

1.07m

2.14m

Figure 3. Leading light plan using rectangle daymark board

front (left) and rear (right) tower

A three-dimensional design software was used to

develop the three-dimension design of the tower and

the simulation area. Figure 4 shows the rectangle,

triangle, and diamond daymark, respectively. The

design of the daymarks were according to the IALA

guideline and fitted on the same size of the tower in

the simulation [7].

Figure 4. Rectangle (left), diamond (middle), and triangle

(right) daymarks

To determine the most effective daymark shape

among the three designs, the simulation videos were

made using the SketchUp plugin features. The

effectiveness was determined based on one criterion,

namely the most easily spotted daymark from the

maximum distance of 2560 m, which was the starting

point of the leading line No. 7 and No. 9 from the

leading line No. 8 and No. 10. The vessel then moved

progressively towards the front tower. At least three

simulation runs were conducted for three different

daymark shapes for each expert. The three experts

were nautical lecturers with unlimited competency

certificates voyage deck officers. The simulation runs

were displayed using a 17-inch monitor gaming

laptop with a high-performance graphic card. The

caption of the simulation run is shown in Figure 5.

The three experts agreed that the diamond shaped

daymark board (centre) was the most easily spotted

from the maximum distance compared to the

rectangle (left) and triangle (right) shape in Figure 5.

Reason for the diamond shape daymark can be

spotted easily compared to the triangle and

rectangular shapes because it has a larger surface area.

The surface area of the diamond shape front tower

was 4.41 m2 (2.1 m [L] x 2.1 m [W] compared to the

rectangle shape with an area of 2.205 m2 (2.1 m [L] x

1.05 m [W] and the triangle shape with an area of 1.10

m2 (2.1 m [L] x 1.05 m [W] x 0.5). However, the

diamond shape mark had the highest wind resistance.

Therefore, the diamond shape was spotted first,

followed by the rectangle and triangle, which

corresponded to the surface areas. In addition, the

diamond shaped mark was easy to identify because it

had a distinctive shape compared to its background.

500

Figure 5. Caption of three videos moving towards the front

tower stopped at the same time for rectangle (left), diamond

(centre) and triangle (right) shape daymark.

As the vessel moved closer towards the front

tower, the diamond shaped daymark was the first

shape which lost its function when the daymark at the

rear tower could not be. The second daymark shape

which lost its function was the triangle, and finally the

rectangle. The distance at which the daymark lost its

effectiveness is referred to as the minimum distance

and is shown in Table 3. This shows that the diamond

shaped daymark board was relatively less effective

when closer to the front tower. This is because the

diamond shaped daymark had a relatively shorter

pointer shape (1.05 m) between the front and the rear

daymark compared to the rectangle and triangle

board with 2.10 m. The vertical stripes red and white

of the rectangle board could not be seen from a

distance of 2560 m. Only the rectangle shape of the

daymark could be identified.

Table 3. Minimum distance range according to shape of

daymark

_______________________________________________

Shape Minimum Distance (m)

_______________________________________________

Diamond 218

Triangle 198

Rectangle 158

_______________________________________________

4 CONCLUSION

The leading light or mark is an AtoN used to mark the

safe navigation channel to a port. The leading

daymarks were used during daytime operations,

while the leading light was used during the night.

Currently, there are three daymarks which are widely

used, namely rectangular, triangular and the

diamond. The objective of this study was to determine

the most effective shape for the leading mark. The

results showed that the diamond shaped daymark

was the most effective shape for the leading mark and

could be easily spotted from a certain distance due to

its relatively larger surface area and distinct shape.

This finding fulfilled the research objective. However,

as the ship moved towards the front tower, the

diamond shaped daymark was the first which became

ineffective, followed by the rectangle and triangle

shaped daymarks. Another downside of the diamond

shaped daymark is its higher wind resistance

compared to the rectangle and triangle shapes due to

its relatively larger surface area. This research is

expected to give much better technical information to

the maritime safety authorities, such as the Marine

Department of Malaysia, the Light Dues Board, and

port authorities, in order to established leading lights

or marks for port usage.

REFERENCES

[1] IALA, “Aids to Navigation Manual 2014,” vol. 7th.

IALA, St Germain En Laye, 2014. [Online]. Available:

http://www.iala-aism.org

[2] IALA, “IALA Guideline 1077 Maintenance of Aids to

Navigation.” IALA, Sa, France, 2009.

[3] IALA, “Search in IALA publications,” 2022.

https://www.iala-aism.org/guidance-

publications/search-in-publications/ (accessed Jun. 15,

2022).

[4] WhatsApp, “whatsapp features.pdf,” 2022.

https://www.whatsapp.com/features (accessed Jul. 25,

2022).

[5] Trimble Inc., “SketchUp,” 2022.

https://www.sketchup.com/products/sketchup-pro

(accessed Jun. 15, 2022).

[6] IALA, “IALA Guideline 1094 Daymarks for Aids to

Navigation,” no. Edition 2.0. Saint Germain en Laye,

2016.

[7] IALA, “Guidelines for the Design of Leading Lines,” no.

December. pp. 1–37, 2001.

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https://webapp.navionics.com/?lang=en#boating@9&key

=%7D~wX%7DdsvR (accessed Jun. 15, 2022).

[9] R. Rowlett, “Lighthouses of Malaysia: West Malaysia

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https://www.ibiblio.org/lighthouse/myw1.htm (accessed

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[10] X. B. Olba, W. Daamen, T. Vellinga, and S. P.

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10.3390/JMSE8010010.