Merchant Shipping Act, 1951 (Act No. 57 of 1951)

Regulations

Merchant Shipping (Collision and Distress Signals) Regulations, 2005

Annex I : Positioning and Technical Details of Lights and Shapes

8. Intensity of lights
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(a)        The minimum luminous intensity  of lights shall be calculated by using the formula:

 

I  =  3,43  x  106  x  T  x  D2  x  K-D

 

where: I    is luminous intensity in candelas under service conditions

T    is threshold factor  2 x 10-7 lux;

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

K    is atmospheric transmissivity.

For prescribed lights the value K shall be 0,8, corresponding to a meterorological visibility of approximately 13 nautical miles.

 

(b)        A selection of figures derived from the formula is given in the following table:

 

Range of visibility (luminous range) of light in nautical miles

 

D

Luminous intensity of light in candelas for K  =  0,8

 

I

1

0,9

2

4,3

3

12

4

27

5

52

6

94

 

Note:The maximum luminous intensity of navigation lights should be limited to avoid undue glare. This shall not be achieved by a variable control of the luminous intensity.