Crown Princess propulsion issues again

[chengkp75]

2 minutes ago, tuckerboxbill said:

Apologies, it was from VibeGuy but I misquoted: " If you’re a Marine Traffic subscriber, look at the historical track data for Crown.  She ain’t going anywhere fast of late - max 10kts over the last two weeks. "

Thanks.  When did the itinerary change email go out, and when did the ship get underway for Seattle?  Just trying to decipher the whole scenario without speculation.

[JeffT237]

1 minute ago, chengkp75 said:

Thanks.  When did the itinerary change email go out, and when did the ship get underway for Seattle? 

I received the email on Wednesday the 27th, I believe the Crown got underway sometime this morning.

 

[chengkp75]

3 minutes ago, JeffT237 said:

I received the email on Wednesday the 27th, I believe the Crown got underway sometime this morning.

 

Thanks.

[VibeGuy]

It’s also possible (unfortunate, but possible) that there are (substantial) flow restrictions between the seawater intake and the cold seawater side of the exchanger.  Pipes are smooth when they leave the factory and the ocean is filled with life adapted to saltwater that likes to cling to solid things for support.  Drink an Oreo shake through a cocktail stir-stick for a demo. 

 

The operating conditions where one could address this mid-voyage could be generously described as “somewhat limited” and might require that such work only be done while alongside, such as with access to shore power, or while the entire load is carried exclusively by the other engine room.
 

Ultimately, a commercial decision has been made here.  It’s a *tiny* bit of a mystery why it’s so late in coming when there’s another (perfectly good) ship or two in a similar state of hotel operational readiness and perhaps better mechanical condition just bobbing around, but it is not for us mere mortals to know. 

[cruisingpeople]

8 minutes ago, VibeGuy said:

 Pipes are smooth when they leave the factory and the ocean is filled with life adapted to saltwater that likes to cling to solid things for support.  Drink an Oreo shake through a cocktail stir-stick for a demo.

Nice analogy/description.

[cruisefan2012]

I`m on the Crown on 22nd September 2022 from Vancouver to California so I hope they manage to fix her !!

[brisalta]

19 minutes ago, VibeGuy said:

It’s also possible (unfortunate, but possible) that there are (substantial) flow restrictions between the seawater intake and the cold seawater side of the exchanger.  Pipes are smooth when they leave the factory and the ocean is filled with life adapted to saltwater that likes to cling to solid things for support.  Drink an Oreo shake through a cocktail stir-stick for a demo.

 

So you are suggesting toxic waste is stuck in the pipes.

[VibeGuy]

Neither Oreos nor marine life are toxic waste.  I would gladly eat a majority of varieties of either. 

[chengkp75]

41 minutes ago, VibeGuy said:

Pipes are smooth when they leave the factory and the ocean is filled with life adapted to saltwater that likes to cling to solid things for support.

This is why the ships have a "MGPS or Marine Growth Protection System", just inside the sea chest (typically in the sea strainer), that uses a small electric current to "dissolve" a copper anode to provide a toxin for marine growth in the SW piping.  But, if this was secured during layup, and significant growth happened in the pipes, then when the MGPS starts working again, you will get "die off", just as you do when sea water temperature changes, and this dead growth will then flow along the pipe to the cooler strainer or cooler plates.  A few years ago, my ship was at anchor for 300+ days a year for 3+ years, with minimum SW flow, and we did not see significant growth in the piping, but we kept the MGPS working all the time.  The system also has an aluminum anode to prevent electrolytic corrosion of the pipes, but that is another topic.

 

The sea chests may be significantly fouled.  These are large "boxes" in the hull, where the SW is drawn in to the SW piping.  These would need to be cleaned by divers, the gratings across the openings (about 2' x 2') are hinged so  a diver can open them, and enter the sea chest to scrape the fouling off.

 

While marine growth is not toxic, I would not eat the stuff that gets caught in the strainers and coolers, as this has been poisoned by copper.  Even the shrimp that we get in the strainers by the garbage can load in the Galveston ship channel twice a year, is not real appetizing.

[VibeGuy]

FWIW, the most efficient speed in terms of fuel burnt per hour for Crown/Ruby/Emerald is somewhere north of 15kts .  Doing 12 up the coast has got to tingle. 

[VibeGuy]

There haven’t been any revenue sailings for 26 months and the last I knew she was out of the greater LA Harbor area was for a brief sail to Ensenada in January to swap some crew, entertainment and hotel staff with Ruby at midnight.    She’s been both at anchor and alongside at various points since then and the highest speed made that I have data for is 10.1kts.  So your guess is as good as mine as to when they knew they had a problem and that it wouldn’t be resolved by the return to revenue service next week, and in fact they may need until the end of July. 
 

I do think Princess is taking a tactical approach that nothing gets resolved in a normal timeline at the moment and that adjusting all the voyages through July is better than adjusting through June and having something come up and not being able to complete the repairs in time and having to roll another month of delay.   The incremental approach hurt their credibility last year, and their entire west coast expansion/return to operation for this season has been a little chaotic -  witness the changes to which ships are running the Vancouver-Whittier line hauls, the LA summer season churn, now this.  They don’t have the customer-facing resources to deal with normal ops right now, so even a single change to a single voyage adds pressure.  I also think that the shoreside / shorex ecosystem is a little brittle right now, so it’s in the interest of Princess to not go back and forth with whether or not a vessel will call in Ketchikan on a given voyage.  Say it won’t, live with the suck, and make it worth Hoonah’s while. 

[chengkp75]

4 minutes ago, VibeGuy said:

FWIW, the most efficient speed in terms of fuel burnt per hour for Crown/Ruby/Emerald is somewhere north of 15kts .  Doing 12 up the coast has got to tingle. 

I've got to disagree with you on this.  The most efficient speed is when whatever combination of engines that are online are loaded to 75-80%.  So, any way you want to combine the following engines:  4 engines at 7920kw (75% of 10,560kw, and 2 engines at 5940kw (75% of 7920kw) gives optimum fuel consumption.  2 x 16V, 2 x 16V +1 x 12V, or 2 x 16V + 2 x 12V, and so on combinations.  With diesel electric drive, the efficiency is in the diesel engine loading, not the motor loading (propulsion).  And, with ship's propellers, the power to speed curve is exponential, so at low speed, you have a wide range of speed that requires very little difference in fuel consumption (horizontal part of curve), while at the 15 knot range (for a ship that can make 21 knots), the incremental power for each knot of speed increases dramatically (vertical part of curve).  The 12-15 knot range would be her "eco speed".

[1965]

I've googled but can't find the answer. Why do propulsion problems cause itinerary changes? It's happened to us a couple of times. We're not booked on the Crown but I read it has caused itinerary changes for an upcoming Alaskan cruise on her. I'm just curious. Would like to learn what I can. Thanks.

[brisalta]

30 minutes ago, VibeGuy said:

Neither Oreos nor marine life are toxic waste.  I would gladly eat a majority of varieties of either. 

 

I beg to differ with regard to Oreos.

[brisalta]

I suggest you read the full thread:

 

 

[VibeGuy]

Quoting Captain Nash of Ruby on why we made big loops at 16kts vs a direct route to San Diego at a much lower speed after weather forced us past a port. I was actually very surprised to hear him choose 16.  Maybe there were guests who wanted to water ski. 

[VibeGuy]

Avoiding shrimp from the Houston channel is probably a solid idea regardless of the harvest method. 

[chengkp75]

24 minutes ago, VibeGuy said:

Quoting Captain Nash of Ruby on why we made big loops at 16kts vs a direct route to San Diego at a much lower speed after weather forced us past a port. I was actually very surprised to hear him choose 16.  Maybe there were guests who wanted to water ski. 

16 knots allows you to make the maximum amount of water, while slower speed reduces the water production.

[VibeGuy]

Algebra. 
 

If the distance between two ports is D miles and the time available to sail between them is T hours, then the speed achieved by the ship must be greater than or equal to D/T. 
 

The ship must arrive at Victoria by 7pm the day before the end of the cruise.  This is effectively non-negotiable.  So the distance she can cover prior to that is limited by the time she departs the previous port and the maximum speed she can reach under current mechanical conditions. 
 

Order of magnitude, it’s 900 miles between the mouth of glacier bay and the pier in Victoria.  The ship has to clear glacier bay at 3pm on Wednesday and be in Victoria at 7pm on Friday.  This is a span of 51 hours (time zone shift included). 
 

If they sail at a constant speed of 17.6 statute miles per hour, they can do so.  If they stop for three hours in Hoonah as the current plan, they have to make 18.75.
 

 If they go to Ketchikan and stay the customary six hours, the situation worsens.  Leaving Ketchikan at 3pm Thursday they have 27 hours to go 625 miles.  That would require a speed of 23 mph  aka 20kts, which is towards the upper end of the range of this ship in perfect condition. 
 

it’s not a vast conspiracy.  It’s just maths 

 

[VibeGuy]

Good point.  I always assume they hook up a garden hose in domestic ports to bunker water. 

[1965]

VibeGuy thank you! I actually understand what you wrote. And I was/am terrible in algebra. 🙂

[chengkp75]

1 hour ago, VibeGuy said:

Good point.  I always assume they hook up a garden hose in domestic ports to bunker water. 

The problem with shore water is that it must be kept segregated, for at least 24 hours until a coliform bacteria test comes back negative.  

[JimmyVWine]

I think the solution to the problem resides here:

 

[ImperialLady]

2 hours ago, VibeGuy said:

Algebra. 
 

If the distance between two ports is D miles and the time available to sail between them is T hours, then the speed achieved by the ship must be greater than or equal to D/T. 
 

The ship must arrive at Victoria by 7pm the day before the end of the cruise.  This is effectively non-negotiable.  So the distance she can cover prior to that is limited by the time she departs the previous port and the maximum speed she can reach under current mechanical conditions. 
 

Order of magnitude, it’s 900 miles between the mouth of glacier bay and the pier in Victoria.  The ship has to clear glacier bay at 3pm on Wednesday and be in Victoria at 7pm on Friday.  This is a span of 51 hours (time zone shift included). 
 

If they sail at a constant speed of 17.6 statute miles per hour, they can do so.  If they stop for three hours in Hoonah as the current plan, they have to make 18.75.
 

 If they go to Ketchikan and stay the customary six hours, the situation worsens.  Leaving Ketchikan at 3pm Thursday they have 27 hours to go 625 miles.  That would require a speed of 23 mph  aka 20kts, which is towards the upper end of the range of this ship in perfect condition. 
 

it’s not a vast conspiracy.  It’s just maths 

 

thanks for the explanation that even I could understand.

[brisalta]

4 hours ago, chengkp75 said:

The problem with shore water is that it must be kept segregated, for at least 24 hours until a coliform bacteria test comes back negative.  

 

Now that is an interesting point!