What is the meaning of "Operational Overnight"?

[telecheck]

 

I am interested in the Pacific coastal cruise on Discovery from Los Angeles to Vancouver from 4/26/23 to 4/30/23.

On the night of 4/29/23, on the travel itinerary, it says "Vancouver, Canada Operational Overnight".

What does "Operational Overnight" mean exactly? Does it mean that the ship will actually arrive at 10:30pm on 4/23 but I won't be allowed to disembark until 6am the following morning?

If this is the case, what is the purpose of mentioning this term? Why not just simply say that the disembarkation time will be on 4/30 at 6am?

 

[cr8tiv1]

The Royal Class ships are having trouble fitting under the Lions Gate Bridge when entering/leaving Vancouver.  They must sail under the bridge at low tide.  Unfortunately, tidal accuracy only occurs a few weeks before.  

 

My best guess is that the Discovery will need to transit this area in the evening if she wants to be at the dock for a 6 AM disembarkation.

 

It is too early to see the port schedule for Vancouver.

https://www.portvancouver.com/wp-content/uploads/2022/08/2022-Cruise-Schedule-as-of-Aug-4.pdf

 

[dides]

1 minute ago, cr8tiv1 said:

The Royal Class ships are having trouble fitting under the Lions Gate Bridge when entering/leaving Vancouver.  They must sail under the bridge at low tide.  Unfortunately, tidal accuracy only occurs a few weeks before.  

 

Yes, we were on the Vancouver-LA Discovery coastal a couple of weeks ago and she had to come into Vancouver around 3am and delay departure until midnight because of the low tides.

[cr8tiv1]

4 minutes ago, dides said:

Yes, we were on the Vancouver-LA Discovery coastal a couple of weeks ago and she had to come into Vancouver around 3am and delay departure until midnight because of the low tides.

 

I saw you tied up.  Both you and the Royal had midnight departures.  Nice to have that extra time in Vancouver.  

 

 

I am not a fan of the Royal Class ships.  This problem AND too big to do the inland passage.  

Edited October 8, 2022 by cr8tiv1

[startedwithamouse]

Also, your casino will be closed. (Shops usually close early night before disembarkation)

[cr8tiv1]

Way to early for you to remember this, but you will need to close your casino account before you start entering Vancouver Harbor.  

[MileHighAko]

Yes this means based on current schedule you will arrive in Vancouver at 10:30 PM on Saturday, but the cruise continues to operate as normal overnight. You’ll clear the port and be able to disembark on Sunday morning. I’ve seen this term on other itineraries before.  

[sloopsailor]

On 10/8/2022 at 2:54 PM, cr8tiv1 said:

The Royal Class ships are having trouble fitting under the Lions Gate Bridge when entering/leaving Vancouver.  They must sail under the bridge at low tide.  Unfortunately, tidal accuracy only occurs a few weeks before.  

 

Tidal fluctuations are known years in advance for almost anywhere on the planet.  It is a simple matter of referencing moon and sun positions which are very predictable and easy to determine.  

[cr8tiv1]

35 minutes ago, sloopsailor said:

 

Tidal fluctuations are known years in advance for almost anywhere on the planet.  It is a simple matter of referencing moon and sun positions which are very predictable and easy to determine.  

 

I agree, but not sure where I read that the actual times can only be predicted a couple of weeks ahead.  Of course, that reference point escapes me now.  Just one of those trivia points that I file in the back of my head.  I am sure there are many factors involved and with such little clearance for the Royal Class Ships, even minor changes will be important.

 

This is the best I could google:

  https://tidesandcurrents.noaa.gov/pdf/Tide_Prediction_Error_for_the_United_States_Coastline.pdf

 

"Differences between predicted and observed tides will be greater than average during extreme weather events and during above normal river runoff to stations on tidal rivers. Errors in time and height of tide are generally larger for those areas with weaker tides."

 

 

[sloopsailor]

50 minutes ago, cr8tiv1 said:

 

I agree, but not sure where I read that the actual times can only be predicted a couple of weeks ahead.  Of course, that reference point escapes me now.  Just one of those trivia points that I file in the back of my head.  I am sure there are many factors involved and with such little clearance for the Royal Class Ships, even minor changes will be important.

 

This is the best I could google:

  https://tidesandcurrents.noaa.gov/pdf/Tide_Prediction_Error_for_the_United_States_Coastline.pdf

 

"Differences between predicted and observed tides will be greater than average during extreme weather events and during above normal river runoff to stations on tidal rivers. Errors in time and height of tide are generally larger for those areas with weaker tides."

 

 

You are absolutely correct. One weather event that can affect tidal anomalies is a LOW ATMOSPHERIC PRESSURE event that appears in the area. This can result in higher water levels due to the LOW resulting in reduced weight of the air on the water surface, allowing the water to rise. High winds can also push water towards the location in question. When these occur in concert with high tidal events, water levels can be several feet higher than during the normal twice a day water level fluctuation.

 

This is what happens in Venice, Italy several times per year, where significant portions of the city can be flooded when these extreme high water events, called Aqua Alta (High Water), occur. The multi billion dollar Mose flood gate project is nearing completion and the hope is that it will protect this vulnerable city from being slowly destroyed by high water incursion as climate change results in world wide higher water level issues. 

Edited October 10, 2022 by sloopsailor

[Roberto256]

On 10/9/2022 at 7:12 PM, sloopsailor said:

 

Tidal fluctuations are known years in advance for almost anywhere on the planet.  It is a simple matter of referencing moon and sun positions which are very predictable and easy to determine.  

Agree completely.   There is nothing about "knowing a few weeks before".

The rotation  of the earth, the orbit of the earth, and the orbit of the moon are quite predictable.

 

Back in my formative years, we would buy a paper back book of tides and tidal current tables for the upcoming year.

 

If you are in a slow moving boat, or in a situation where every second matters (like racing) knowing the tidal current

is a great assist.

 

In my neighborhood, it was eldridge, but maybe something like this for the pacific coast:

 

 

Which had diagrams like this: