‘Safety of navigation’ anyone know?

[Wolfsrule]

So I already posted that I just got off the carnival Conquest but there was one part of the cruise that confused me. We were in cabin 6202 right at the front of the ship and two decks below the bridge. Anyone know what the actual issue is here? Or do they just not want people peeping in at night? I kept the curtains closed every night after sunset like they asked but I’ve never seen that before.

[bury me at sea]

I have read the light from cabins above and below the bridge can impair the night vision of those on the bridge.

[shof515]

it reduces the glare from the bridge windows at night

Edited June 22, 2019 by shof515

[ShakyBeef]

Yes, what the PPs said.  DH and I were fortunate to have one of the two coveted extra-large picture window cabins directly under the Bridge on the Celebrity Mercury.  Our cabin had a similar sign, for the same reason.

[Homosassa]

This is standard procedure for any cabin on any cruise line where the cabin lights will interfere with the night vision of the crew on the bridge. 

[crooooze]

That nuts! They designed a $500 million cruise ship in the 21st century with state of the art technologies and didn’t think of a modern day way to mitigate this?? 

This wasn’t an issue when they manned a crow’s nest? Geez!

[chengkp75]

3 hours ago, crooooze said:

That nuts! They designed a $500 million cruise ship in the 21st century with state of the art technologies and didn’t think of a modern day way to mitigate this?? 

This wasn’t an issue when they manned a crow’s nest? Geez!

I hope this was meant humorously, but if not, the problem is not with technological aspects of the ship, the problem is with the Mk1 human eyeball.  Every ship in the world, from the simplest coasting steamer to a multi-billion dollar warship, with cruise ships in between, darken foredecks, and shade all forward facing windows to aid the human eye in retaining night vision.  This is why bridges are kept pitch black at night, with only a few red lamps available (red light wavelength does the least damage to night vision), and areas like the access to the bridge will turn off the lights automatically when the door is opened, or chart tables are curtained off, and the officers need to take time when transiting from the light of the chart table to the darkness of the bridge to regain their night vision.  No technology that I'm aware of has improved the human eye over the millenium.

 

And, as to the "crow's nest", just look where that got the Titanic, where the lookout didn't spot the berg until it was nearly upon them.  The darkened bridge and the blackout forward of the bridge is actually a result of the Titanic.

[gnegron22]

13 minutes ago, chengkp75 said:

I hope this was meant humorously, but if not, the problem is not with technological aspects of the ship, the problem is with the Mk1 human eyeball.  Every ship in the world, from the simplest coasting steamer to a multi-billion dollar warship, with cruise ships in between, darken foredecks, and shade all forward facing windows to aid the human eye in retaining night vision.  This is why bridges are kept pitch black at night, with only a few red lamps available (red light wavelength does the least damage to night vision), and areas like the access to the bridge will turn off the lights automatically when the door is opened, or chart tables are curtained off, and the officers need to take time when transiting from the light of the chart table to the darkness of the bridge to regain their night vision.  No technology that I'm aware of has improved the human eye over the millenium.

 

And, as to the "crow's nest", just look where that got the Titanic, where the lookout didn't spot the berg until it was nearly upon them.  The darkened bridge and the blackout forward of the bridge is actually a result of the Titanic.

Great explantion, I knew a little bit about this but explained some more.. Thank you

[Wolfsrule]

45 minutes ago, chengkp75 said:

I hope this was meant humorously, but if not, the problem is not with technological aspects of the ship, the problem is with the Mk1 human eyeball.  Every ship in the world, from the simplest coasting steamer to a multi-billion dollar warship, with cruise ships in between, darken foredecks, and shade all forward facing windows to aid the human eye in retaining night vision.  This is why bridges are kept pitch black at night, with only a few red lamps available (red light wavelength does the least damage to night vision), and areas like the access to the bridge will turn off the lights automatically when the door is opened, or chart tables are curtained off, and the officers need to take time when transiting from the light of the chart table to the darkness of the bridge to regain their night vision.  No technology that I'm aware of has improved the human eye over the millenium.

 

And, as to the "crow's nest", just look where that got the Titanic, where the lookout didn't spot the berg until it was nearly upon them.  The darkened bridge and the blackout forward of the bridge is actually a result of the Titanic.

Thank you so much for the excellent explanation!!! I probably will book a similar cabin again on a future cruise because I loved it and know I understand why the curtains remain closed.

[ProgRockCruiser]

We stayed in one of the Scenic Ocean View cabins on Elation - the cabins right at the front of the ship on the top (interior) deck with  floor to ceiling and wall to wall windows.  They also had such placards.  We slept with the lights off, no TV, didn't turn on the light for the bathroom etc, so we left the blinds open all night.  Really quite nice view at night!

[Elaine5715]

46 minutes ago, ProgRockCruiser said:

We stayed in one of the Scenic Ocean View cabins on Elation - the cabins right at the front of the ship on the top (interior) deck with  floor to ceiling and wall to wall windows.  They also had such placards.  We slept with the lights off, no TV, didn't turn on the light for the bathroom etc, so we left the blinds open all night.  Really quite nice view at night!

I was planning to do the same when I stayed in a 4J with the "secret deck" in front but my female cabin steward warned me that those cabins attract window peepers.  😮

[crooooze]

2 hours ago, chengkp75 said:

I hope this was meant humorously, but if not, the problem is not with technological aspects of the ship, the problem is with the Mk1 human eyeball.  Every ship in the world, from the simplest coasting steamer to a multi-billion dollar warship, with cruise ships in between, darken foredecks, and shade all forward facing windows to aid the human eye in retaining night vision. 

 

It was a bit of sarcasm... I know about how the the human eye works with night vision, and so should the people who design the bridges and cruise ships...

 

I would have thought the architects and engineers would have considered how to keep light from forward facing cabins from interfering with night vision in the bridge. Posting a sign requesting the passengers to close their curtains seems like an aftermarket solution, and one that is probably not very reliable.

 

 

Edited June 23, 2019 by crooooze

[chengkp75]

1 hour ago, crooooze said:

 

It was a bit of sarcasm... I know about how the the human eye works with night vision, and so should the people who design the bridges and cruise ships...

 

I would have thought the architects and engineers would have considered how to keep light from forward facing cabins from interfering with night vision in the bridge. Posting a sign requesting the passengers to close their curtains seems like an aftermarket solution, and one that is probably not very reliable.

 

 

Even indirect, ambient lighting will affect night vision, so as long as the light is shining outside, whether directed at the bridge, or just adding to ambient lighting like a city's lights do, will affect night vision.  Most cruise ship bridges will have shades on any aft facing, and many side facing windows to prevent the ambient light spillage from the side of the ship affecting their vision.  The only other way to avoid this "light spillage" would be to have all the forward facing cabins behind and below the bridge by a considerable margin (i.e. having the bridge jut out forward of the cabins), and even then it would degrate night vision to an extent.  Those who have never experienced the extreme dark of night at sea (and a cruise ship is anything but dark), don't understand how a single small light can affect your ability to see dim objects in the dark.

[ShakyBeef]

2 minutes ago, chengkp75 said:

So, every ship in the world that turns their bridge lights off at night (and every single one does) is doing so for no good reason?  Oh, and by the way, every ship afloat in the ocean, including cruise ships, have a crew member whose job function is "lookout" both night and day.  They no longer stand in a "crow's nest" but on the bridge wings, or inside the bridge, or on the bow of the ship, depending on the weather and the operations.  I assume this is no longer required?  Most ships have a radar "blind spot" that can extend for nearly a mile in front of the ship, where the "very expensive electronics" cannot detect anything.  Further, those "very expensive electronics", since they are adjusted to not register waves as radar targets, also cannot detect low lying objects.  Oh, almost forgot, all those "very expensive electronics" that US Naval vessels use, didn't preclude the USS Fitzgerald from colliding with an enormous container ship, or the USS McCain from colliding with an oil tanker.  Tell those 17 sailors who lost their lives in those incidents that use of a human eye to distinguish a large, slow moving merchant ship, with running lights lit, wasn't imperative.

 

PREACH!

 

I wish I could hit the "Like" button more than once for this one!

[midcarolina]

I have no idea why the Navy does things they do......but I know if human night vision was critical for safe navigation submarines would be screwed......

[chengkp75]

1 hour ago, midcarolina said:

I have no idea why the Navy does things they do......but I know if human night vision was critical for safe navigation submarines would be screwed......

And, yet a submarine will have a few Mark 1 eyeballs up on the sail when on the surface, every time, everywhere, where there are more dangers present.  Have you ever navigated a ship at night?  Why does the IMO, through SOLAS, as well as the USCG require human lookouts when a ship is under navigation, if their input was "useless" and "ridiculous".

[joepeka]

1 minute ago, chengkp75 said:

And, yet a submarine will have a few Mark 1 eyeballs up on the sail when on the surface, every time, everywhere, where there are more dangers present.  Have you ever navigated a ship at night?  Why does the IMO, through SOLAS, as well as the USCG require human lookouts when a ship is under navigation, if their input was "useless" and "ridiculous".

Well Chief, it appears that someone stayed at a Holiday Inn Express last night so I applaud your patience. The submarine reference was non sequitur and a bit of a desperate attempt at defense. 

[chengkp75]

1 hour ago, joepeka said:

Well Chief, it appears that someone stayed at a Holiday Inn Express last night so I applaud your patience. The submarine reference was non sequitur and a bit of a desperate attempt at defense. 

Another Chief I worked with years ago was also a dedicated Trans-Pac sailor.  He had spent many a night alone at the helm of his sailboat, under sail power, in all oceans of the world.  The scariest incident he had was off Key West one night, when he saw a yellow rotating light underwater.  Yep, that was a US Navy sub surfacing within 100 feet of his boat, despite all the most sophisticated electronics available at the time, they didn't see his fiberglass sailboat (about 36') with no engine running.

[coevan]

We always sail with red lights in the cabin on any night passages. 

[chengkp75]

1 hour ago, coevan said:

We always sail with red lights in the cabin on any night passages. 

Why?  Totally useless.  Use your electronics.  

[Haoie]

Nice job Chief! Informative as always.

[midcarolina]

15 minutes ago, coevan said:

We always sail with red lights in the cabin on any night passages. 

Thats a different use of a red light!

[sanmarcosman]

 Carnival adding " Thanks! " to the sign as a complimentary close trivializes the import of the message to my ear. They may as well add a smiley emoji to the sign, too. 

[coevan]

it's right above my nav station, thought that was what is for, my chartplotter is in the cockpit, not the salon. I rarely if ever sit at the nav station. I am always on deck on my watch. We are talking about a 40' sailboat, Florida-Bahamas or BVI-SXM. 

[evandbob]

3 hours ago, chengkp75 said:

Even indirect, ambient lighting will affect night vision, so as long as the light is shining outside, whether directed at the bridge, or just adding to ambient lighting like a city's lights do, will affect night vision.  Most cruise ship bridges will have shades on any aft facing, and many side facing windows to prevent the ambient light spillage from the side of the ship affecting their vision.  The only other way to avoid this "light spillage" would be to have all the forward facing cabins behind and below the bridge by a considerable margin (i.e. having the bridge jut out forward of the cabins), and even then it would degrate night vision to an extent.  Those who have never experienced the extreme dark of night at sea (and a cruise ship is anything but dark), don't understand how a single small light can affect your ability to see dim objects in the dark.

 

Thanks for another accurate explanation chengkp75.

 

If anyone wants to try an experiment with eye adjustment at night, drive around with your car's dashboard lights on bright for 5 minutes then try to see detail when looking to the right or left.

 

Then dim the dashboard lights as low as they can go, and see the difference after another 5 minute adjustment.

 

Remember how another car's bright beams would temporarily blind you?  Same principle.  I'm sure an optometrist can share the science behind our pupil's expansion and contracting effected by exposure to ambient lighting or sudden brightness