Did they fix Nieuw Amsterdam's azipod or is she sailing with one operational?

[MisterBill99]

18 minutes ago, HappyInVan said:

HAL cancelled that cruise. Immediately, booked the NA into Freeport wetdock.

 

To me, it suggests that HAL already had a diagnosis from the pod OEM. That Freeport would be the place to confirm the solution and effect the repairs.
 

On last Tuesday afternoon, HAL was able to announce that the 21^st departure would proceed. Means that they'd opened up the azipod, and proceeded with repairs. The NA being tied up in Freeport till Friday.

 

 

I know you want to end the discussion, but there was no evidence that they did the repair. They cancelled the first cruise because the approval to sail with a damaged azipod was not received in time. Presumably they could have gotten that approval by Tuesday.  And if you look at the quote from the HAL announcement, if you were to announce that the ship will be sailing under reduced power, the obvious next part would be exactly what HAL said -- "The ship has been cleared as safe to sail by several regulatory authorities and meets all international safety standards."  If the ship were fully repaired, why would they need to say that?

 

In any event, hopefully we will know by the end of the day.

Edited December 22, 2019 by MisterBill99

[AL3XCruise]

1 hour ago, HappyInVan said:

You're probably right. Looks like the safe rating per azipod is @12 knots max. I doubt that one azipod could be run at 15 knots for extended periods?

 

You are making an assumption that there is a linear relationship between speed and power.  That is incorrect, the relationship is exponential.  As speed increases, each additional knot takes significantly more power than the one before it.  Thus it is quite reasonable the ship can operate at well over half its cruising speed on half the power.  15+ knots continuously does not seem unreasonable.

[VennDiagram]

1 hour ago, MisterBill99 said:

I know you want to end the discussion,

 

Remember, people have the option of ignoring threads if they no longer want to read what is being said 😉

 

Edited December 22, 2019 by VennDiagram

[tamsno]

Still a bit concerned about repositioning Ft Lauderdale to Barcelona 4/04/20 and the Med beyond.  If in fact full repairs were not made, would they attempt a 6-day transatlantic on one pod which would eliminate redundancy?  Hopefully, this saga is indeed not over yet.

[MisterBill99]

2 minutes ago, tamsno said:

Still a bit concerned about repositioning Ft Lauderdale to Barcelona 4/04/20 and the Med beyond.  If in fact full repairs were not made, would they attempt a 6-day transatlantic on one pod which would eliminate redundancy?  Hopefully, this saga is indeed not over yet.

 

If the repairs were not made, they still have a full three months to do them before the TA. One would expect them to do it before then, during a week that would cost them less and disappoint less people.

[HappyInVan]

2 hours ago, AL3XCruise said:

 

You are making an assumption that there is a linear relationship between speed and power.  That is incorrect, the relationship is exponential.  As speed increases, each additional knot takes significantly more power than the one before it.  Thus it is quite reasonable the ship can operate at well over half its cruising speed on half the power.  15+ knots continuously does not seem unreasonable.

 

I'm assuming that the single motor has to move twice the weight, and the propellers work twice (?) as fast.

 

If the ship has so much excess capacity, why limit the vessel's speed to 24 knots?

 

IMHO, only the OEM shipyard engineers understands these issues for the NA. He had to construct the vessel with the help of computer modelling.

 

 

 

 

[old mike]

Math is your best friend,

propulsion power is opposed by drag , for  turbulent flow which is applicable, the drag is proportional to speed squared. 

Using dimensionless ratios one azipod should easily  attain 15 knots even allowing for the asymmetrical thrust.

 

basis as follows

 

top speed 24 knots, the  square root of 24 is about  4.9 which equates to the thrust from two azipods.

the presently demonstrated speed is 15 knots,  the square root of 15 is about 2.3 which is less than 50% of the equivalenced thrust from two azipods at a nominal 2.5 

 

I still prefer a slide rule over computers or calculators.

 

 

Edited December 22, 2019 by old mike

[chengkp75]

3 hours ago, HappyInVan said:

 

 

From the wiki page on NA...

 

"Speed:    
23.9 knots (44.3 km/h; 27.5 mph) max
21.8 knots (40.4 km/h; 25.1 mph)"

 

You're probably right. Looks like the safe rating per azipod is @12 knots max. I doubt that one azipod could be run at 15 knots for extended periods?

 

Perhaps there has been a partial repair on the failed pod, as others have mentioned.

 

 

There is no "safe rating" for an azipod for vessel speed.  Vessel speed depends on many factors like the available horsepower, and weather conditions, and even the condition of the hull below the water (fouling).  The rating of an azipod is the maximum power it can provide.  So, one azipod can provide 50% of the total propulsion power the ship is designed for.  Now, if the relationship between propeller power and vessel speed was linear, you would be correct, but it is an exponential relationship, so an increase of 5 knots from 10 to 15 knots requires much less power than an increase in speed of 5 knots from 15 to 20 knots.  Half power will typically give 60-75% of vessel rated speed.

[chengkp75]

27 minutes ago, HappyInVan said:

 

I'm assuming that the single motor has to move twice the weight, and the propellers work twice (?) as fast.

 

If the ship has so much excess capacity, why limit the vessel's speed to 24 knots?

 

IMHO, only the OEM shipyard engineers understands these issues for the NA. He had to construct the vessel with the help of computer modelling.

 

 

 

 

No, the motor does not work "faster".  The azipod has a rated rpm, which does not relate to vessel speed in a linear relationship any more than power does.  Here is a link to a paper on power and vessel speed, please look at page 6 to see the graph of power required to vessel speed.

 

https://www.usna.edu/NAOE/_files/documents/Courses/EN400/02.07 Chapter 7.pdf

 

The ship does not have "excess" power, the power of two pods is what is required to move the ship at 24 knots.

 

Sorry, but the relationship between ship power and vessel speed is a basic of naval architecture, and while the exact factoring is different for each vessel, the gross relationship is the same for all.

[HappyInVan]

24 minutes ago, chengkp75 said:

No, the motor does not work "faster".  The azipod has a rated rpm, which does not relate to vessel speed in a linear relationship any more than power does.  Here is a link to a paper on power and vessel speed, please look at page 6 to see the graph of power required to vessel speed.

 

 

 

Ahhh. So the propeller will work at the same speed?

 

 

[MisterBill99]

So, my suspicions were correct!  I had replied to the post on the Holland America Line PartnerSHIPS Facebook page thread that included "The ship has been cleared as safe to sail by several regulatory authorities and meets all international safety standards."  HAL replied: "Nieuw Amsterdam has been approved as completely safe to sail with one azipod propulsion system by all relevant authorities."

 

I replied and asked what the plans to repair it and when they would announce the impact of future sailings.

 

Looking forward to hearing from @wesport on what they find out on the ship.

Edited December 22, 2019 by MisterBill99

[NavArch64]

I am a naval architect … I am watching NA depart Nassau with 2 tugs standing by … her asymmetrical wake is exactly the same as when she left PEF to go to Freeport to the shipyard. There has been no change. She appears only to have the port AZIPOD operational … there is no wake on the starboard side. I certainly could be wrong … but this is my best observation.

[HappyInVan]

22 minutes ago, MisterBill99 said:

 HAL replied: "Nieuw Amsterdam has been approved as completely safe to sail with one azipod propulsion system by all relevant authorities."

 

 

 

Wait a moment. Isn't that what they said about the 747 MAX?

[HappyInVan]

9 minutes ago, NavArch64 said:

I am a naval architect … I am watching NA depart Nassau with 2 tugs standing by … her asymmetrical wake is exactly the same as when she left PEF to go to Freeport to the shipyard. There has been no change. She appears only to have the port AZIPOD operational … there is no wake on the starboard side. I certainly could be wrong … but this is my best observation.

 

 

Thanks. Too bad. Obviously there are handling, NV and safety issues.

 

Hope that they will still go forward with the repairs whenever the ship is in port. Assuming that this is a Version X Azipod.

 

 

[wesport]

[VMax1700]

21 minutes ago, HappyInVan said:

 

Wait a moment. Isn't that what they said about the 747 MAX?

It is 737 Max and Boeing don't make azipods 😉

[NavArch64]

If there is anyone currently onboard NA, is it possible to post a screen shot of the display in the Crows Nest of the AZIPOD RPM's … that would certainly clarify the visual observations.

[wesport]

Looks like 1 and a quarter

[MisterBill99]

1 minute ago, NavArch64 said:

If there is anyone currently onboard NA, is it possible to post a screen shot of the display in the Crows Nest of the AZIPOD RPM's … that would certainly clarify the visual observations.

 

Wespot was going to do that but has been posting pictures of the wake.

[tamsno]

Thanks for the comments and pics.  Back to my earlier comment regarding the April transatlantic I'm booked on, won't this have to be fixed before then?

[HappyInVan]

13 minutes ago, wesport said:

 

 

Looks like just turbulence around the pod. Hope that HAL will offer compensation to you.

[MisterBill99]

1 minute ago, tamsno said:

Thanks for the comments and pics.  Back to my earlier comment regarding the April transatlantic I'm booked on, won't this have to be fixed before then?

 

You've got three months, why are you worrying? Yes, I am sure they will fix it before then. People with cruises in January should be concerned until they hear of the short-term plans.

[MisterBill99]

1 minute ago, HappyInVan said:

 

Looks like just turbulence around the pod. Hope that HAL will offer compensation to you.

 

For what, the vibration? They did not change the itinerary other than returning an hour late.

[Oceansaway17]

well I wonder how long the will ask for tug assistance and how much it costs.

To me, anything broken should get fixed as quickly as possible. 

 

More and more pods having issues, ships are back to doing things the old way with tugs. Allure of the Seas has an issue too.

 

On another note, after two Carnival collided in Cozumel, I notice when Carnival ship in Ft. Lauderdale was backing out yesterday, a tug was very close by and backed out with it.  But no line were attached  but rather just kind of babysitting it was it back out.  Thought that was interesting.

 

[VMax1700]

4 minutes ago, HappyInVan said:

 

 

Looks like just turbulence around the pod. Hope that HAL will offer compensation to you.

Why?  🤔🙄

because the wake is 'unbalanced'??