Bart Senior wrote:

1 pt each

C'mon, I want more than one measly point!



What is a range, and how are two lights used to establish a range?

A range is two markers that should be kept in line with each other to
follow a channel, like looking down a gun sight. The upper light is the
further marker.

Care should be taken when following a range to know the marks for
*leaving* the range, I have seen plenty of range markers on dry land.




Why would three lights be used?

?? Dunno, maybe to mark a danger bearing?


What are the factors that determine a single light's visible range?

The height and the brightness




How are red sector in lights used?

To mark a danger zone or a "no-approach" zone.


Why are lighthouses all designed differently?

You mean why do they have different colored & patterned stripes etc on
them? So you can tell which is which, and thus where you are, if your
GPS is broken! However many lighthouses do have the same colors or
pattern.


At night, what danger should a helmsman be aware of when
steering for a lighted bouy that is being used as a way point?

Be wary of hitting the darn thing. Also, in some places, be wary of
hitting unlit markers along the same channel, or old out-of-service
marks. It can be a real PITA.


What is a Morse Code "A" light mean?

Sea buoy, the outermost channel marker entering a larger port. Small
sea channels won't have this.

Good questions Bart. Thanks

Fresh Breezes- Doug King

DSK wrote:

Bart Senior wrote:


1 pt each


C'mon, I want more than one measly point!



What is a range, and how are two lights used to establish a range?


A range is two markers that should be kept in line with each other to
follow a channel, like looking down a gun sight. The upper light is the
further marker.

Care should be taken when following a range to know the marks for
*leaving* the range, I have seen plenty of range markers on dry land.




Why would three lights be used?


?? Dunno, maybe to mark a danger bearing?


What are the factors that determine a single light's visible range?


The height and the brightness


To be more precise, the height determines the geographic range while
visible range is limited by conditions as well as luminosity and colour.


Cheers (call me Nav)

Nav wrote:

(call me Nav)

There are those on this ng who would call your Nav but you didn't
give his/her phone number.

--
Flying Tadpole

-------------------------
Break Away, Sail Away and putz away
now at http://music.download.com/internetopera

Nav wrote:

To be more precise, the height determines the geographic range while
visible range is limited by conditions as well as luminosity and colour.

Very good. But you jumped ahead, when you mention geo range you should tell
about luminous range.


Cheers (call me Nav)

OK, Navvie

Fresh Breezes- Doug King

Same for you. Need a little more detail to get a point for the one
question listed below.

Nav wrote

DSK wrote:

Bart Senior wrote:


1 pt each
What are the factors that determine a single light's visible range?

The height and the brightness


To be more precise, the height determines the geographic range while
visible range is limited by conditions as well as luminosity and colour.


Cheers (call me Nav)

It is remarkable that you prefer a long winded yet incomplete answer to
that which gives _all_ the factors without being longwinded. Was may
answer not precise enough?

:P

Cheers


Bart Senior wrote:

Same for you. Need a little more detail to get a point for the one
question listed below.

Nav wrote

DSK wrote:


Bart Senior wrote:



1 pt each
What are the factors that determine a single light's visible range?

The height and the brightness


To be more precise, the height determines the geographic range while
visible range is limited by conditions as well as luminosity and colour.


Cheers (call me Nav)

You didn't account at all for the curvature of the earth.

Yes, I do prefer more complete answers. The idea here
is to pass on information to other readers. Details count.

Nav wrote
It is remarkable that you prefer a long winded yet incomplete answer to
that which gives _all_ the factors without being longwinded. Was may
answer not precise enough?

Bart Senior wrote:
Same for you. Need a little more detail to get a point for the one
question listed below.

DSK wrote:
Bart Senior wrote:

1 pt each
What are the factors that determine a single light's visible range?

The height and the brightness

To be more precise, the height determines the geographic range while
visible range is limited by conditions as well as luminosity and colour.

Cheers (call me Nav)

Hah! If the earth was not curved height would not be the primary
determinant of geographic range. You've still ignored the question of
color which has a very large effect.

Cheers

Bart Senior wrote:
You didn't account at all for the curvature of the earth.

Yes, I do prefer more complete answers. The idea here
is to pass on information to other readers. Details count.

Nav wrote

It is remarkable that you prefer a long winded yet incomplete answer to
that which gives _all_ the factors without being longwinded. Was may
answer not precise enough?

Bart Senior wrote:

Same for you. Need a little more detail to get a point for the one
question listed below.


DSK wrote:

Bart Senior wrote:


1 pt each
What are the factors that determine a single light's visible range?

The height and the brightness


To be more precise, the height determines the geographic range while
visible range is limited by conditions as well as luminosity and colour.

Cheers (call me Nav)

Nav wrote:

Hah! If the earth was not curved height would not be the primary
determinant of geographic range. You've still ignored the question of
color which has a very large effect.

You are free to explain at length, if you wish. Or, if you don't like it
here, you're free to go away. Your call.

DSK

For additional information. The first thing you see on a very clear night,
when the clouds are reflective overhead of the light source, and/or when the
distant light is very strong, is 'light loom.' That's the reflection of the
light up into the sky and what you are seeing is not in direct line of
sight. Altitude off the surface of the water still counts though so the
higher you are the better off you are. The reflection can be of lights 30
to 50 miles off depending on the source. For example the lights of Miami,
NewYork, Los Angeles or any other big city. On a good viewing night loom
from Miami area can be seen out as far as the Bahamas. Normally though you
are seeing light loom from a ship and the brightest lights are, invariably,
fishing vessels. They use strong deck lights when night fishing for these
reasons. Illuminate the deck working area, show they are 'shooting nets'
and sometimes to attract the fish. As the light source draws near we see
the source directly from our 120' vantage point out a bit further than 24
miles due to the combined heights. The higher the light source the farther
we see it. One light, on the top of a mountain in the Canary Islands can be
easily seen from our bridge wings at 40 miles and that's further than our
radars will operate. Of course the light is many hundreds of feet above us.
Light loom, under good viewing conditions, is a good advance indicator of
things to come. Early warning device as it were. Multiple light looms
often help us navigate between those rock filled waves (straits for
example) or give warning of increased surface activity ahead (such as the
fishing fleets around the entrance to the Med, both ends of Suez, the Red
Sea etc. On a lower to the surface sailboat I couldn't hope to see at those
distances BUT by using light loom reflections I can increase my range of
visibility in many situations beyond simple direct vision. A useful tool at
the very least.

M.


"Bart Senior" wrote in message news:EW%Fc.13086$kz.3
...
You didn't account at all for the curvature of the earth.

Yes, I do prefer more complete answers. The idea here
is to pass on information to other readers. Details count.

Nav wrote
It is remarkable that you prefer a long winded yet incomplete answer to
that which gives _all_ the factors without being longwinded. Was may
answer not precise enough?

Bart Senior wrote:
Same for you. Need a little more detail to get a point for the one
question listed below.

DSK wrote:
Bart Senior wrote:

1 pt each
What are the factors that determine a single light's visible range?

The height and the brightness

To be more precise, the height determines the geographic range while
visible range is limited by conditions as well as luminosity and
colour.

Cheers (call me Nav)