Dry Dock Information?

[rhinomike]

Is there a website or maybe a thread here on CC with dry dock info? I know over on the Carnival forum they always have a thread with dry dock info. The Spirit is going into dry dock in January. I am wondering how long and what they will do to her. Thank you.

[AquamarineBreeze]

That might be an interesting thread just to keep up with various ncl dry docks.

I THINK the Spirit will be in dry dock for about ten days Jan 30/31 - Feb 10/11.

[rhinomike]

Yes it would be. I can't find NCL dry dock information anywhere.

[che5904]

OP where did you hear that the spirit was going in for drydock? According to Wikipedia it was just refurbished in 2011.

 

I don't know if all ships are on here but here's a link from CC

 

http://www.cruisecritic.com/articles.cfm?ID=521

[chengkp75]

OP where did you hear that the spirit was going in for drydock? According to Wikipedia it was just refurbished in 2011.

 

I don't know if all ships are on here but here's a link from CC

 

http://www.cruisecritic.com/articles.cfm?ID=521

 

Drydocking and refurbishment are two different things. Drydockings are required every 2.5 years to inspect and maintain the areas and equipment below the waterline. Cruise ships typically use this time to "spruce up" the hotel, new carpets, new TV's, new upholstery. A refurbishment is where they tend to renew furniture in cabins and public spaces, change the décor of the ship, and/or add new/different public spaces. If the Spirit was last docked in 2011, then it is due for drydocking again.

 

If she is scheduled for a 10-14 day docking, as someone posted, then it will most likely be "lipstick and rouge". Since she is in Europe full time, I'm not sure if they are planning to put the new dining venues that the Epic, Breakaway, etc get for the US market.

[barnacle_boy]

Newer passenger ships can go 5 years between dry-dockings. However, after they reach 15 years of age, as did Spirit, they have to dry-dock every 2.5 years. Chengkp75, as a cruise ship engineer, what do you think of the 15 year milestone? Do ships really tend to become less dependable around the 15 year mark? Is there anything that occurs to make IWS less reliable or accurate?

[chengkp75]

Newer passenger ships can go 5 years between dry-dockings. However, after they reach 15 years of age, as did Spirit, they have to dry-dock every 2.5 years. Chengkp75, as a cruise ship engineer, what do you think of the 15 year milestone? Do ships really tend to become less dependable around the 15 year mark? Is there anything that occurs to make IWS less reliable or accurate?

 

At the 15 year interval, you reach the 3rd special survey, and starts the requirement for more ultrasonic thickness checks of hull plating, and this can only be done with only air on both sides of the steel. Some construction, and some classification societies require x-ray inspection of certain critical welds, and again, this needs to be done in air. There is usually also some more steel replacement in the ship's tanks, and this welding is not easily done to specification when one side is wet. And yes, the rudder bearings, shaft seals, and shafting need more frequent inspections up close and personal. UWILD (underwater survey in lieu of drydocking), or what you call IWS is done by a diver, with the surveyor watching video. At 15 years, most surveyors will want to walk the hull themselves to see every inch up close.

 

One reason that many cruise ships still drydock twice in 5 years (the actual requirement, not every 2.5 years), is that the anti-fouling paints allowed in most countries do not last sufficiently to keep the ship clean for 5 years, and there are even less places every year where you can get divers to clean the hull underwater, again for environmental reasons. With the size and speed of the cruise ships today, a clean hull is essential.

[barnacle_boy]

I was going to say the same to you regarding the 2 dry-docking per every 5 year period with duration between dry-docks not to exceed 3 years, but the initial 2.5 you said earlier is a more practical answer since most schedule them that way to have the fewest dry-dockings whilst still being in compliance. In which ports are ships allowed to clean their hulls in the water? Are there any on typical cruise itineraries that would allow for this sort of cleaning? Most brand new ships still opt for the 5 year periods, which seems to imply that the costs associated with dry-docking (taking the ship out of service, etc.) outweigh the costs of having a hull covered in marine growth.

 

I'm not sure what you mean by "speed" though, considering a lot of cruise ships, and other types of merchant vessels, are sailing at reduced speeds due to higher fuel rates when possible. I suppose what I'm asking is, does marine growth equally effect the performance of a ship no matter what speed she is traveling at? I always assumed that the faster the ship is traveling, the greater the effect of the marine growth in lower performance and greater cost. How much can 5 years of growth shave off a ship's speed and add to fuel burn? Obvious even the same ship can vary slightly from year to year, but very broadly, generally speaking. As a passenger, I like seeing a clean hull (assuming the water is clear enough to see) and boot topping, but it seems like they've all grown "fuzzy" in what I assume is the companies' quest to save money by minimizing dry-dockings.

[chengkp75]

I was going to say the same to you regarding the 2 dry-docking per every 5 year period with duration between dry-docks not to exceed 3 years, but the initial 2.5 you said earlier is a more practical answer since most schedule them that way to have the fewest dry-dockings whilst still being in compliance. In which ports are ships allowed to clean their hulls in the water? Are there any on typical cruise itineraries that would allow for this sort of cleaning? Most brand new ships still opt for the 5 year periods, which seems to imply that the costs associated with dry-docking (taking the ship out of service, etc.) outweigh the costs of having a hull covered in marine growth.None any more that I can think of, though there may be some in the deep south Caribbean. It used to be common place to get divers in Miami to brush the hull and props. In places like Galveston, where you can anchor more than 10 miles out, you can still have divers clean the hull, but it is generally a several day operation.

 

I'm not sure what you mean by "speed" though, considering a lot of cruise ships, and other types of merchant vessels, are sailing at reduced speeds due to higher fuel rates when possible. I suppose what I'm asking is, does marine growth equally effect the performance of a ship no matter what speed she is traveling at? I always assumed that the faster the ship is traveling, the greater the effect of the marine growth in lower performance and greater cost. How much can 5 years of growth shave off a ship's speed and add to fuel burn? Obvious even the same ship can vary slightly from year to year, but very broadly, generally speaking. As a passenger, I like seeing a clean hull (assuming the water is clear enough to see) and boot topping, but it seems like they've all grown "fuzzy" in what I assume is the companies' quest to save money by minimizing dry-dockings.

 

While most cargo ships have reduced speed to save fuel, and cruise ships speed is itinerary dependent hull fouling is still a big problem. Does marine growth affect ships differently at different speeds? Simple answer, yes. Complex answer, yes but in different ways. Now I'll get pretty technical.

 

First off, the speed a ship travels at will affect how quickly marine growth accumulates. The faster she goes, the more the water acts as an abrasive and removes the baby barnacles and seaweed. Likewise, time spent in fresh water (Baltimore, New Orleans) tends to kill off sea growth, but encourage fresh water marine growth, but that is killed when the ship goes to sea again.

 

Slip is the measurement of the difference between how fast the ship should be going, and what it actually is doing. Think of a propeller as a wood screw. For every turn of the screw, it advances into the wood a distance equal to the pitch or distance between threads. This is what we call engine speed: how many revolutions per hour of the propeller should push the ship forward so many miles. When you ratio this to the actual speed of the ship, the percentage is called "slip".

 

Marine growth contributes to slip. A ship that is anchored for 6 months off Galveston can gain 10-20% of slip, meaning that the engines have to work 10-20% harder to move the ship as it did when the hull was clean.

 

Now comes speed. The horsepower required to push a ship through the water is around the square of the speed (not exact, but it will do). Therefore, the difference in power required to increase speed between 15 knots and 17 knots will be about 4 times as much as the difference to increase between 13 and 15 knots (again, an approximation). The fuel required to create the horsepower it also about the square of the horsepower, in other words, the fuel consumption goes up quite a bit for the last few horses (anyone who drives a car knows this). So, to increase the speed of a ship at the top end, requires a whole lot more fuel than a similar increase at slower speeds. When you add in the increased slip, this brings the fuel consumption to the "really bad" area.

 

The fuzzy beard you see at the waterline is not real significant in terms of ship's efficiency. This will tend to stream along as the ship moves, and is only over a very small percentage of the hull surface. Growth accumulates here first because it is closest to sunlight. The real killer of ship speed and fuel consumption are barnacles. These can be as small as 1/4", but if covering a significant area of hull, they destroy the smooth hydrodynamics of the hull, and ruin the fuel economy.

 

The really good anti-fouling paints are what are called "self-polishing copolymers", which means that when the anti-fouling agent (mostly tin these days) is leached from the outer surface of the paint by the marine growth (causing it to die), the ship's speed will polish off the ineffective paint, exposing a new layer of anti-fouling agent. These paints, while no more toxic to the marine environment than others, are more toxic when applied, and are no longer allowed in the US.

 

Sorry for the ramble.

[CruisinMaterial]

Wow... nice ramble... that was quite informative! Thanks for sharing the information! :)

[chengkp75]

Wow... nice ramble... that was quite informative! Thanks for sharing the information! :)

 

Yeah, probably could have done just as well saying, at slow speed hull growth would add 20-30% to fuel consumption, while at higher speeds it can add 40-50%. Sometimes shorter is better.

[mypleasure]

OP where did you hear that the spirit was going in for drydock? According to Wikipedia it was just refurbished in 2011.

 

I don't know if all ships are on here but here's a link from CC

 

http://www.cruisecritic.com/articles.cfm?ID=521

 

I was on the Spirit last summer and was told about the dry dock early 2014 and said no way as it was dry docked in 2011. When I went to book for Feb 2014 I couldn't as she is in dry dock the week we wanted. Going Jan 6th instead.

[Single Cruiser]

So the question I have is Epic has itineraries through to Nov 2015. I can't see any gaps for her dry dock?

[barnacle_boy]

Thanks for the in-depth reply, chengkp75! I chose the name barnacle_boy because I've been known to be a drag sometimes. Unfortunately they are nasty looking critters. I never really thought about how slip and increasing horsepower interacted with each other.

 

Epic is pretty limited in her options for dry-docking. I assume that she'll go before starting her summer season in Europe. Maybe Blohm + Voss in Hamburg? Might also be done at Grand Bahama.

[CruisinMaterial]

Yeah, probably could have done just as well saying, at slow speed hull growth would add 20-30% to fuel consumption, while at higher speeds it can add 40-50%. Sometimes shorter is better.

 

No need I followed pretty well and the explanation was definitely detailed enough to follow with basic knowledge of maritime stuff. Nice work on the explanation!

 

I found it intriguing about the paint they use on the bottom of the ship. I know they said it was to make the ship glide more smoothly through the water but I didn't know it had a toxic effect on the barnacles and such growing there. Interesting stuff!

[CruisinMaterial]

So the question I have is Epic has itineraries through to Nov 2015. I can't see any gaps for her dry dock?

 

Now Craig are you implying the Epic needs a dry dock? What have you done to her? :eek::p:D

[chengkp75]

No need I followed pretty well and the explanation was definitely detailed enough to follow with basic knowledge of maritime stuff. Nice work on the explanation!

 

I found it intriguing about the paint they use on the bottom of the ship. I know they said it was to make the ship glide more smoothly through the water but I didn't know it had a toxic effect on the barnacles and such growing there. Interesting stuff!

 

Yes, the anti-fouling agent, which used to be copper (worked really well) but has been changed to tin (less toxic to larger organisms) is absorbed through the attachment point and poisons the barnacle or seaweed.

[Single Cruiser]

Now Craig are you implying the Epic needs a dry dock? What have you done to her? :eek::p:D

 

Lol. I'm saying she's 5 in June 2015 and she's never been out of the water or any gaps in the itineraries to do so! :confused:

 

 

Code Certificate Term Issued Expires

Ext. until

CLCE Classification Certificate Full 2011-01-20 2015-06-17

Edited December 14, 2013 by Single Cruiser

[CruisinMaterial]

Lol. I'm saying she's 5 in June 2015 and she's never been out of the water or any gaps in the itineraries to do so! :confused:

 

 

Code Certificate Term Issued Expires

Ext. until

CLCE Classification Certificate Full 2011-01-20 2015-06-17

 

They might still be working on securing a berth for her during the current seasons and will cancel depending on when a slot opens up. They'll probably do it in Europe season and not in Freeport. It seems Carnival and RCI tie up Freeport quite a bit. NCL ships tend to dry dock all over the place (Vancouver, Alabama and here in Boston). :cool: