First-time Transatlantic-sunrise/sunset times

[steve4031]

I'm a first timer for next summer too.  When is sunset and sunrise as you cross the Atlantic.  I'm thinking the daylight hours are longer because the ship takes a great circle route that goes further north as you leave New York City.  

[exlondoner]

16 minutes ago, steve4031 said:

I'm a first timer for next summer too.  When is sunset and sunrise as you cross the Atlantic.  I'm thinking the daylight hours are longer because the ship takes a great circle route that goes further north as you leave New York City.  

I imagine it depends on the date. You lose an hour going east most days, gain one going west. NYC is a long way South of Southampton anyway.

[TheOldBear]

17 minutes ago, steve4031 said:

I'm a first timer for next summer too.  When is sunset and sunrise as you cross the Atlantic.  I'm thinking the daylight hours are longer because the ship takes a great circle route that goes further north as you leave New York City.  

The time changes as you travel east and west are much more significant - its not quite one time zone per day, but you have 5 23 hour days eastbound, and 5 25 hour days westbound.

[BigMac1953]

For 5 days travelling east, it's a 23 hour day. Conversely for 5 days going west, its a 25 hour day..

 

We're doing the round trip in August so will experience both (again).

[buchanan101]

15 minutes ago, steve4031 said:

I'm a first timer for next summer too.  When is sunset and sunrise as you cross the Atlantic.  I'm thinking the daylight hours are longer because the ship takes a great circle route that goes further north as you leave New York City.  

Interestingly the ship does not necessarily - or even usually - take the great circle route. On the westbound October crossing the captain said that unusually we were detouring further NORTH to get a smoother crossing; and that detour to the north took us on to a Great Circle route. This implies that the usual route is to the south of the GC - and diversions to avoid the worst weather are usually southwards.

 

Look how far north of that infamous iceberg we were... 

[buchanan101]

2 minutes ago, TheOldBear said:

The time changes as you travel east and west are much more significant - its not quite one time zone per day, but you have 5 23 hour days eastbound, and 5 25 hour days westbound.

Yes - Change, Change, no change, change, no change, change, change

[exlondoner]

2 minutes ago, buchanan101 said:

Interestingly the ship does not necessarily - or even usually - take the great circle route. On the westbound October crossing the captain said that unusually we were detouring further NORTH to get a smoother crossing; and that detour to the north took us on to a Great Circle route. This implies that the usual route is to the south of the GC - and diversions to avoid the worst weather are usually southwards.

 

Look how far north of that infamous iceberg we were... 

I believe in April 1912 the icebergs were unusually far South.

[BigMac1953]

I believe it's either the Great Circle North or the Great Circle South.

 

We travelled eastbound a few years ago on the Southern Circle. It went quite near the Azores so despite the fact that it was November, the weather was fantastic.

[exlondoner]

What is a rhumb line? I think they did that on our TA once.

[TheOldBear]

1 minute ago, exlondoner said:

What is a rhumb line? I think they did that on our TA once.

A rhumb line follows a constant compass heading - they appear as straight lines on a Mercator map projection [the projection where all lines of longitude are parallel, straight up and down]

[Host Hattie]

I've moved the sunrise/sunset question a new thread.

One thing I did notice on our last cruise was how accurate the sunset times given in the Daily Programme were!

[IB2]

15 hours ago, TheOldBear said:

The time changes as you travel east and west are much more significant - its not quite one time zone per day, but you have 5 23 hour days eastbound, and 5 25 hour days westbound.

Yes, that’s the thing you will notice the most.  The time adjustment for the voyage is  five hours but spread over seven days, so each day - in crude terms - the sunrise and sunset times are changing by 40-45 minutes (varying in summer and winter owing to the change in latitude) because of the ship’s travel, which means a ‘clock time’ change of about 15-20 minutes on days when the clock has been adjusted during the 24 hours prior, but a significant jump of 40-45 minutes in the opposite direction on the couple of days when there’s been no change.

[buchanan101]

19 hours ago, exlondoner said:

I believe in April 1912 the icebergs were unusually far South.

That is true of course...which is why they weren't really expecting icebergs there.

[chengkp75]

22 hours ago, BigMac1953 said:

I believe it's either the Great Circle North or the Great Circle South.

 

We travelled eastbound a few years ago on the Southern Circle. It went quite near the Azores so despite the fact that it was November, the weather was fantastic.

Since a Great Circle path is defined as the shortest distance between two points on a sphere, there is only one Great Circle route between two ports.  Between NYC and Southampton, the Great Circle route takes you very far north.

[buchanan101]

Just now, chengkp75 said:

Since a Great Circle path is defined as the shortest distance between two points on a sphere, there is only one Great Circle route between two ports.  Between NYC and Southampton, the Great Circle route takes you very far north.

Correct.  Just one great circle route*. We were effectively on it in October to avoid the worst of the weather - according to the Captain at his noon briefing. Normally, as I said, better and warmer weather is usually to the south of the great circle route

 

(* well I guess there are two - the other would involve sailing off south east across mainland Europe - this maybe "Great Circle South")

[BigMac1953]

Well maybe it was just a Southern Circle, but it certainly wasn't a rhumb line.

[TheOldBear]

Both of our recent crossings [M234 eastbound , M236 westbound] QM2 diverted from the typical great circle routing to avoid weather systems. 

Despite the diversion, the westbound experienced sufficient movement to prompt closure and draining of the deck 12 Pavilion pool and hot tubs. [The spa pool remained open on deck 7 with lots of sloshing; I think the outdoor pools were closed but not drained]

[neeuqdrazil]

2 hours ago, TheOldBear said:

Despite the diversion, the westbound experienced sufficient movement to prompt closure and draining of the deck 12 Pavilion pool and hot tubs. [The spa pool remained open on deck 7 with lots of sloshing; I think the outdoor pools were closed but not drained]

 

At least some of the outdoor pools were drained during that voyage - I remember getting out on the first day that the promenade was open, and noticing empty pools. 

[buchanan101]

14 hours ago, TheOldBear said:

Both of our recent crossings [M234 eastbound , M236 westbound] QM2 diverted from the typical great circle routing to avoid weather systems. 

Despite the diversion, the westbound experienced sufficient movement to prompt closure and draining of the deck 12 Pavilion pool and hot tubs. [The spa pool remained open on deck 7 with lots of sloshing; I think the outdoor pools were closed but not drained]

My point was that the captain said that sailing Great Circle is *not* the normal route as weather generally worse.  They usually go further south; less economical but more comfortable. I had thought they’d default to Great Circle - seems not

 

the worst we had was chairs sliding around during an art talk in the Queens Room 

[exlondoner]

1 hour ago, buchanan101 said:

My point was that the captain said that sailing Great Circle is *not* the normal route as weather generally worse.  They usually go further south; less economical but more comfortable. I had thought they’d default to Great Circle - seems not

 

the worst we had was chairs sliding around during an art talk in the Queens Room 

On my first crossing, on QE2, Captain Hazel apparently took us 600 miles south of our planned course to avoid a storm. It was still very rough that night, and the next morning a thousand people missed breakfast. It was a Sunday, and we sang For Those in Peril on the Sea extremely fervently in the morning service.

[buchanan101]

30 minutes ago, exlondoner said:

On my first crossing, on QE2, Captain Hazel apparently took us 600 miles south of our planned course to avoid a storm. It was still very rough that night, and the next morning a thousand people missed breakfast. It was a Sunday, and we sang For Those in Peril on the Sea extremely fervently in the morning service.

QE2 was only about half the size of QM2 wasn't it? I was a little surprised (ok, not really) that 150,000 tons and quad stabilised QM2 moved at all...

 

 

[chengkp75]

30 minutes ago, buchanan101 said:

QE2 was only about half the size of QM2 wasn't it? I was a little surprised (ok, not really) that 150,000 tons and quad stabilised QM2 moved at all...

 

 

Stabilizers do nothing for pitching, and do not stop rolling.  Stabilizers are designed to slow the ship's rolling motion to a more comfortable speed.  The thought that 4 small stabilizer wings could counteract the rolling force of 80,000 tons of ship is just not realistic.

[buchanan101]

7 minutes ago, chengkp75 said:

Stabilizers do nothing for pitching, and do not stop rolling.  Stabilizers are designed to slow the ship's rolling motion to a more comfortable speed.  The thought that 4 small stabilizer wings could counteract the rolling force of 80,000 tons of ship is just not realistic.

I know they won't stop it  - I was joking - also they are reactive I assume; predictive stablisers would be interesting. Rolling is more uncomfortable than pitching I think... (QM2 was also yawing a bit as the sea was from the starboard bow)

 

All very interesting...I am now deep in to google and Metacentric height etc.. (I'm an engineer, so it's all very interesting)

 

A blog post about the original QM before it had stablisers fitted 🤢

 

https://www.rcgroups.com/forums/showthread.php?1265090-RMS-Queen-Mary-Prior-to-Stabilizers-An-Engineers-Story

Edited December 8, 2022 by buchanan101

[chengkp75]

The stabilizers require a small amount of rolling motion to start reacting.  Their purpose is to change the roll period, by introducing force at a different time than the wave.

 

An interesting note regarding the QM2, is that after sea trials, where it was found that the 4 azipods did not provide any lateral stability (ability to keep to a steady course) in following seas, that the ship went back into dry dock, and a "skeg" or wedge shaped extension was added to the after end of the keel, to provide the needed stability.

[buchanan101]

Just now, chengkp75 said:

The stabilizers require a small amount of rolling motion to start reacting.  Their purpose is to change the roll period, by introducing force at a different time than the wave.

 

An interesting note regarding the QM2, is that after sea trials, where it was found that the 4 azipods did not provide any lateral stability (ability to keep to a steady course) in following seas, that the ship went back into dry dock, and a "skeg" or wedge shaped extension was added to the after end of the keel, to provide the needed stability.

Surely the period is the same, but in anti-phase, just like noise cancellation

 

Works fine with a steady noise, or wave period, but if the wave period varied could be problematic - but I guess that can't really happen

 

QE, QV, QA only have two azipods don't they - do they also provide the steering?