Half Speed and Shut in


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Paul Lee

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Aug 11, 2003
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Hi all,
Just two questions:

After the collision, the engine room telegraphs were rung "half speed ahead". What is this? Is it half maximum speed? Would that make it about 10-12 knots?

Also, what angles abaft the beam would the Titanic's masthead lights, stern light and side lights be "shut out"?

Best wishes

Paul
 
Oct 28, 2000
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Paul--

Masthead Light -- Shines from dead ahead through an arc of 112 1/2 degrees on either side of the beam (total arc of 225 degrees).

Sidelight -- Shines from dead ahead through an arc of 112 1/2 degrees to port (red) or starboard (green). Note that the combined sidelights have the same total arc of visibility as the masthead light. Today's Rules require sidelights to be mounted on the outboard ends of the bridge wings (I'm not sure about 1912 regulations).

Sternlight -- Shines through an arc of 135 degrees dead astern. (Fills in the "piece of pie" not filled by the masthead light.

Titanic had only a forward masthead light. The after masthead light was authorized in 1912, but not required on ships of Titanic's length. Today, all power-driven ships over 50 meters in length must display an after masthead light higher than the forward masthead light.

Sailing vessels do not show masthead lights, but do show sidelights and stern lights.

The cutoff point at which an observer stops seeing side or masthead lights and can see only the sternlight is used to define the difference between an overtaking situation and a meeting/crossing situation in the Rules Of The Road. Sidelights are carefully masked in the forward direction so that no colored light shines across the stem.

--David G. Brown
 

Paul Lee

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Aug 11, 2003
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Hi David,
Thanks for your help! I remember the discussion in "The Ship That Stood Still" about Titanic only having only (foreward) light!

Best wishes

Paul
 
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