Royal Caribbean orders new Icon Class of 5,000 pax LNG fueled ships

[chengkp75]

13 minutes ago, Saab4444 said:

In Stockholm they fill the big Viking ferry with LNG by truck that comes from Norway every other day I believe. 

Big difference in technology.  The ferries use a pressurized tank to contain the LNG at atmospheric temperature (same as buses or barbeque grills), and also only require a hundred tons or so, if they are fueling every other day.  Cruise ships are using cryogenic LNG systems, that are only pressurized to 2-3 psi (0.1-0.2 bar) but that have to  maintain -260*F (-160*C) to keep the LNG in liquid form.  So, the pipeline from the liquifaction facility needs to be ultra-insulated, or the barges/tankers need to have cryogenic tanks.  Also, these cruise ships will take a couple thousand tons of fuel each week.

[Lloyd555]

A sign at the Meyer Werft shipyard.

 

232,500 GT?!

 

 

200,000 GT

Edited January 25, 2019 by Lloyd555

[Tall-Cruiser]

Wow! Bigger than Oasis Class. Unless Oasis 5 will be much bigger

[Ourusualbeach]

43 minutes ago, Lloyd555 said:

A sign at the Meyer Werft shipyard.

 

232,500 GT?!

 

 

200,000 GT

 

And  5650 passengers at double occupancy.   More than Oasis class.

[Tough as Leather]

More weight but not necessarily bigger than oasis class?

[Ourusualbeach]

3 minutes ago, Tough as Leather said:

More weight but not necessarily bigger than oasis class?

It’s not weight.  It’s interior volume.

[Biker19]

12 hours ago, Ourusualbeach said:

 

And  5650 passengers at double occupancy.   More than Oasis class.

I thought the 5500+ passengers with the 200K GT size didn't make sense and thought the passenger count was off - it seems the GT number was off. Physically, you can get to 232K GT and still be smaller than Oasis.

[Magster1987]

12 hours ago, Biker19 said:

I thought the 5500+ passengers with the 200K GT size didn't make sense and thought the passenger count was off - it seems the GT number was off. Physically, you can get to 232K GT and still be smaller than Oasis.

 

How can a bigger volume be smaller? Gross Tonnage is a messure of volume not weight.

 

Btw, i'm very exited we may have a new class in this size. So many new things they can do to it. 😄

[Pratique]

GT is interior volume I believe. Oasis has a lot of exterior spaces, Central Park, Boardwalk, and is a wide ship.

[Biker19]

9 hours ago, Magster1987 said:

 

How can a bigger volume be smaller?

Icon class will likely not have huge open spaces like Central Park and Boardwalk which don't count in the GT numbers.

 

Biker, who still thinks one of the numbers (either pass or GT) in the Icon class is off.

[chengkp75]

13 hours ago, Magster1987 said:

 

How can a bigger volume be smaller? Gross Tonnage is a messure of volume not weight.

 

Btw, i'm very exited we may have a new class in this size. So many new things they can do to it. 😄

Gross tonnage is not a direct measure of volume.  The old, unused, Gross Registered Tonnage was a direct measure of the ship's volume.  Gross tonnage takes the internal volume and multiplies it times the factor "K", which is an exponential factor with respect to volume.  So, Gross Tonnage will always be less than the actual volume, and the larger the ship's volume, the greater the disparity between the actual volume and the Gross Tonnage.  Gross Tonnage has no units;  it is not "X tons", it is merely "X".

 

But, yes, if you take away the open areas down the middle of the Oasis class, you would have a "smaller" ship with the same Gross Tonnage.  Similarly, open areas that are enclosed by glass walls, like pool decks, but are not totally enclosed on all 6 sides, do not count towards Gross Tonnage.

[Captain Billy Bob]

On 11/27/2018 at 5:39 AM, chengkp75 said:

Big difference in technology.  The ferries use a pressurized tank to contain the LNG at atmospheric temperature (same as buses or barbeque grills), and also only require a hundred tons or so, if they are fueling every other day.  Cruise ships are using cryogenic LNG systems, that are only pressurized to 2-3 psi (0.1-0.2 bar) but that have to  maintain -260*F (-160*C) to keep the LNG in liquid form.  So, the pipeline from the liquifaction facility needs to be ultra-insulated, or the barges/tankers need to have cryogenic tanks.  Also, these cruise ships will take a couple thousand tons of fuel each week.

Can you explain the refueling process? If you know.

Sounds like there are a lot of risks involved.

[JAMESCC]

When do we expect the first ship in this class because this sounds like one interesting project? I can't wait to get reports or artist renderings of this ship class.

[deliver42]

I just got off the Symphony, and they said 2023, but had no further information on it.

[steamboats]

10 hours ago, Captain Billy Bob said:

Can you explain the refueling process? If you know.

Sounds like there are a lot of risks involved.

 

As currently there´s only the AIDAnova running on LNG... The AIDAnova is refueling every two weeks. There are two or three LNG tankers (which also run on LNG). The first one was the Cardissa, the other one is called Coral Methane. Not sure which one is currently doing the job. The Cardissa came alongside in the port of Tenerife and the AIDAnova took on the LNG (which is cooled down to -160°C as Cheng said). AIDA created the position of a special LNG engineer who´s only resposible for everything regarding the LNG. The "tubes" do have double "walls" with liquid nitrogen inbetween. One fueling process did take them 4 hours. You can see photos here (and try to use google translate for the text which is an interview with the current LNG engineer onboard the AIDAnova).

 

steamboats

[chengkp75]

12 hours ago, Captain Billy Bob said:

Can you explain the refueling process? If you know.

Sounds like there are a lot of risks involved.

Steamboats provides a good article on the bunkering operations.  There really aren't a lot of risks, those that exist have been mitigated by procedures that have been developed over decades of LNG operations.  Remember, there have been large ocean-going ships transporting thousands of tons of LNG around the world for 40 years, so the processes needed to pump LNG from ship to ship or shore to ship are well documented.

 

As noted, the LNG tanks, unlike residual fuel tanks, are "inerted", meaning that the air above the liquid fuel in the tank is not just "air" but a gas that has a reduced oxygen content, whether nitrogen or "stack gas" (exhaust gas a device that burns fuel to produce a gas mixture heavy in carbon dioxide and low in oxygen).  When the oxygen content is below 5% (20% is normal "air"), combustion simply cannot happen, so the fuel is non-combustible.

 

The LNG tanks on the cruise ship will be of a thermos bottle design, meaning the tank is double walled with a vacuum in between to act as insulation.  The tank is then housed in another tank, where an inert atmosphere is present, so that if the LNG tank leaks, this tank will still be non-combustible, and has gas sensors in it.

 

When they start to load LNG, you must first spray small amounts of LNG into the tank, allowing it to flash to gas, and this starts the cooling process, as sudden cooling from ambient temperature to the -160*C of the fuel would crack the tank.  Once the temperature in the tank is sufficiently cool, then they can start the "bulk" pumping of LNG into the tank.  Unlike residual fuel oil tanks, which have open vents to allow the air to exit the tank as liquid is pumped in (notice the oil smell when the ship is being bunkered?), LNG tanks are kept at a slight pressure, with vents closed.  In the photos in steamboat's article, you will notice two hoses, one with frost on it (this one is carrying the LNG), and one without frost.  This hose is carrying the gas that is filling the empty tank back to the LNG tanker.  There, is is compressed and cooled, and re-liquified and sent back to the cargo tanks for reuse.

 

 

[Captain Billy Bob]

Thanks steamboats and changkp75. Very informative. I learned something new today.