by Charles Darley

Some details obtained from chatting to those who know!!

Navigation lights

1. Navigation lights should not be shown if the vessel is alongside or aground or at anchor, at all other times she will be deemed to be underway and shall exhibit her steaming lights eg.masthead lights, sidelights and sternlight.


2. Lights should be exhibited from sunset to sunrise and in times of reduced visibility and at any other time when it is deemed necessary. In practice nowadays most ships exhibit navigation lights continuously whilst at sea.


3. The all round red lights (not under command) should be exhibited only with the side lights and stern light. Masthead lights are not exhibited under those circumstances, eg loss of engine, steering etc.

General information on navigation lights

On a power driven vessel of more than 20 metres in length the forward mast headlight (steaming light) is carried at a height above the fore deck of not less than 6 metres and if the breadth of the vessel exceeds 6 metres, then at a height above the hull not less than such breadth. However the light need not be placed at a greater height above the deck than 12 metres.

As MV Scot Ranger is over 50 metres in length it has to carry an after mast headlight and the regulations state that the after light shall be carried at a height of not less than 4.5 metres vertically higher than the forward one.

The arc of visibility of the mast headlights (white) are to be visible in a continuous arc from right ahead to a position 22.5 degrees aft the beam on either side of the vessel. This gives an arc of 225 degrees.

The sidelights of a power driven vessel shall be placed at a height above the hull not greater than three quarters of that of the forward mast headlight.

The arc of visibility of the sidelights shall be from right ahead to a position of 112.5 degrees on their respective sides.

The arc of visibility of the sternlight shall be from right astern to a position of 22.5 degrees aft of the vessels beam on either side. This gives an arc of 135 degrees (from right astern to 67.5 degrees on either side).

The forward and aft anchor lights are white and give an unbroken arc of 360 degrees.

The forward one shall be carried at a height of not less than 4.5 metres above the height of the after one. The forward one is usually located at the masthead as is the case on our vessel.

The all round red lights (not under command ) shall be carried at a position where they can best be seen. The vertical spacing between the lights shall be not less than 2 metres.

What flags are flown and when?

In port the ship will fly the house flag from the port halyard on foremast, if we are in a foreign port we fly their national flag from the starboard halyard foremast and our Red Ensign aft halyard mainmast.

Whilst at sea the ship will not normally fly any flags, due to lack of crew these days, by tradition flags should be flown in port or at sea from sunrise to sunset. At sea a vessel should fly its ensign at the stern of the vessel or in our case the after halyard.

Size of flags

Flag size varies but the house flag and foreign national flags onboard are 140cm x 65cm and our ensign is larger at 36inches x 72inches.

How quickly can the ship MV Scot Ranger turn round?

In calm sea conditions, wind force 3, with the vessel in ballast speed at commence of turn was 12 knots. With the rudder hard over to starboard from a heading of 030 degrees ship was turned through 360 degrees back to 030 degrees. The time taken was 3mins 10secs. At the completion of the turn the speed had dropped to 1.7 knots and the vessel was back in approximately the same position as at commencement of turn. The bowthust was not used as it has no effect at speed.

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