Is Celebrity Edge's engineering fundamentally flawed?

[Host Jazzbeau]

Sailing on Edge right now and noticing that this ship has more creaks and groans – even in calm seas – than any other ship we have sailed on.  Caveat: I am not an engineer, and I hope that chengkp75 will set me straight on this thread straight off!  But I am wondering whether the 'breakthrough' engineering concept behind Celebrity Edge is fundamentally flawed.

 

Here is my non-engineer idea.  Back in the day cars were built as body-on-frame, which was cheap but led to flexing; Detroit finally came around to the European concept of monocoque which makes the outer skin a structural part and allows cars to be much more rigid.  Ships, on the other hand, have always been basically monocoque in design – the outer hull is a major structural component.

 

Celebrity Edge, if my concept holds, is more like a body-on-frame design.  The main structural components were moved inside to the corridor walls, making the entire cabin area a non-stressed external part of the ship.  This allowed the 'infinite veranda' cabins – but it also means that the cabins are much less solid-feeling than on a traditional ship.

 

If Edge flexes as much as I'm experiencing tonight – in calm seas – what will it be like in heavy seas?  [PS – I don't plan to find out.]

[CeleryCruiser]

I suppose that you have sailed with Solstice class ships earlier? They are very well made ships by Meyer Werft in Germany with some Finnish crucial parts like engines and the steering system.

Edge is made by STX France. Unfortunately I Don't have any experience on Edge but I have had some experience of earlier ships and ferries and compared the work quality between different manufacturers. I suppose that I know what you are trying to explain:  its like driving with BMW and comparing the experience with Peugeot....

[ipeeinthepool]

5 hours ago, Host Jazzbeau said:

Sailing on Edge right now and noticing that this ship has more creaks and groans – even in calm seas – than any other ship we have sailed on.  Caveat: I am not an engineer, and I hope that chengkp75 will set me straight on this thread straight off!  But I am wondering whether the 'breakthrough' engineering concept behind Celebrity Edge is fundamentally flawed.

 

Here is my non-engineer idea.  Back in the day cars were built as body-on-frame, which was cheap but led to flexing; Detroit finally came around to the European concept of monocoque which makes the outer skin a structural part and allows cars to be much more rigid.  Ships, on the other hand, have always been basically monocoque in design – the outer hull is a major structural component.

 

Celebrity Edge, if my concept holds, is more like a body-on-frame design.  The main structural components were moved inside to the corridor walls, making the entire cabin area a non-stressed external part of the ship.  This allowed the 'infinite veranda' cabins – but it also means that the cabins are much less solid-feeling than on a traditional ship.

 

If Edge flexes as much as I'm experiencing tonight – in calm seas – what will it be like in heavy seas?  [PS – I don't plan to find out.]

 

As a 37 year veteran of the auto industry, I'll suggest that your analogy is flawed.  Any design concept can be excellent if executed properly.  Your basic assumption that body on frame (BOF) is more rigid is incorrect.   Torsional rigidity of frames is often a difficult issue to resolve in BOF vehicles.  North America BOF approach was a carry over approach from the wagon days (think Fisher Body) and offers a lot of design flexibility without designing major structural and chassis components.  The BOF approach allowed new very different looking cars to be introduced every year in the 50 and 60's without really re-designing the car.  I'll also suggest that although you may be nostalgic about cars from back in the day, your are forgetting that they were terrible for NVH.  Cars from back in the day had lot's of squeaks and rattles.  Today's unibody car designs can be designed with excellent NVH characteristic, largely by increasing the rigidity of the vehicle and incorporating crush zones to provide for safety in the event of a crash.   One of the downsides to this approach is that vehicle designs cannot change as often  because of all of the engineering that has gone into the vehicle.   But you are correct the rigidity of the cars is an important factor in minimizing squeaks and rattles but also very important is the approach that is used to attach interior components  to the body.  All cars will flex and if you allow contact between areas that are moving you will get squeaks and if the attachment is loose you will get rattles.  I'm not smart enough to know if the Edge is less rigid than other ships, but I will suggest that if you are experiencing squeaks and rattles a large factor is probably the way the interior is attached to the ship.  

 

One side note about the auto industry, it may be going back to designing more of a platform approach with different bodies.   Electric cars will require completely new platforms to fully really the potential of an electric car and several manufactures have touted a "skateboard" approach with all of the electric components and different bodies.  This will keep design costs down and still allow for flexibility.  This will be similar to the old BOF approach and is another example of going "Back to the Future"

Edited January 24, 2019 by ipeeinthepool

[justcrusn]

The worst night EVER for us was on Reflection.

The ship creaked and squeaked so much we could not sleep.

Now, this was very heavy seas but still, some ship noise is not unheard of.

[chengkp75]

Thanks for reaching out to me about this.  It will take some time to research this, but from a quick survey I don't see where the structural members have been moved back to the corridors.  My first thought is that the decks are made of thicker steel to take the place of the longitudinal strength members at the outboard end of the decks, and this may still be the case.  Then I saw a different photo of what an IV cabin looks like, and seeing the "bump out" in the area of the settee, I surmise that behind that is a large thwartship structural member carrying the load down to the hull.  By placing more structural vertical supports closer together (most ships only have these at the fire zone boundaries, every 10-15 cabins apart), actually every cabin, they reduce the longitudinal span that the deck needs to carry and eliminates the need for a large longitudinal strength member at the deck edge.  I could be all wrong about this, just working from a few photos and renderings, if you have any articles that discuss their structural design in detail, that would help.

 

Cruise ship cabins are typically modular, and installed already assembled, and I assume the Edge's are as well.  The cabin "walls" (what we call "ceiling", since they are not structural) and "ceiling" (overhead) and deck are thin steel panels screwed together and to thin steel reinforcing channels, and then only fastened to the ship's structure in a relatively few spots.  Traditional balcony cabins have a deck, an overhead, and 4 "walls", of which three are essentially solid (even the door wall has strengtheners around the door openinng like all good construction) and the balcony door wall has at least a strong frame around the glass to strengthen that wall.  The IV cabins appear to have done away with the balcony wall altogether, and when you do this, you create an unstable structure.  Think of a pasta box.  Empty it, and leave the one end with all the flaps open.  Lay it down on the counter, with the wide side down (short side vertical).  Now, press down on the top of the box near the open end, and move your finger back and forth.  The rectangular shape of the open end of the box, now becomes a parallelogram in one direction and then the other, as the box flexes back and forth.  In the case of the IV cabin, that means the light steel cabin interior flexes more than if there were a frame around the balcony wall.  The flexing causes the creaks and groans.

 

Is this a fatal flaw?  Not really.  I don't believe that any class society would approve a design that made the cabins "non-structural", regardless of what a designer wants, or what a non-technical CEO thinks he understands.  So, there won't be any structural or safety problems with this design.  Now, will they have to rethink the structure of the non-structural cabin interior to either strengthen it, or add attachment points to the ship's structure, or a different way to join the panels, that could well be in the future of this ship.

 

I think there are a few concepts about Edge that I don't think were well thought out, like the lack of curtain at the folding glass door, the relative size of the opening glass on the balcony compared to the area above the railing of a standard balcony, the problems with AC when you have a vast number of cabins that can have large openings to the outside, and the problems with ship generated wind on the magic carpet.  Time will tell whether these things prove out or not, but I don't think there are any fatal flaws in the ships themselves.

 

As to the differences between shipyards, again, most of the cabins are not produced in the shipyards, but are manufactured by sub-contractors possibly hundreds of miles from the shipyard, and possibly in Germany for the French shipyard.

[hcat]

Going to take awhile to read through and digest the info. I do recall omin one video LLP remarked about all the columns on the ship , that they were needed and worked around for decor . But is EDGE any different in that regard from other ships?

 

Creakiest ship for us was Mercury..but we loved it anyhow! Our all time favorite .

[Host Jazzbeau]

1 hour ago, ipeeinthepool said:

Your basic assumption that body on frame (BOF) is more rigid is incorrect.  

 

Well, you completely mis-read my post.  I said that body on frame "leads to flexing" and that monocoque is more rigid.  But thanks for confirming my memories of how bad cars from the 50s were for NVH and handling.

[Host Jazzbeau]

Thanks chengkp75 for replying.  I knew that we would get a thoughtful, informed explanation from you!  I'm not in an IV cabin, but the one next to me is – and that is the wall that does most of the creaking.

[ipeeinthepool]

27 minutes ago, Host Jazzbeau said:

 

Well, you completely mis-read my post.  I said that body on frame "leads to flexing" and that monocoque is more rigid.  But thanks for confirming my memories of how bad cars from the 50s were for NVH and handling.

 

The bigger take-away should be all designs will flex and move and the sub-systems need to be designs to accommodate the movement from either approach.  Perhaps the support of HVAC, water, waste systems or the attachment of the interior walls to the hull have not been designed to accommodate movement in what you perceive to be nominal sea conditions.  Eventually the design will encounter some rough seas where there will be squeaks and rattles, but the design should be robust enough limit any squeaks and rattles to more extreme conditions.

[mnocket]

3 hours ago, hcat said:

Going to take awhile to read through and digest the info. I do recall omin one video LLP remarked about all the columns on the ship , that they were needed and worked around for decor . But is EDGE any different in that regard from other ships?

 

Creakiest ship for us was Mercury..but we loved it anyhow! Our all time favorite .

Yeah I remember the same video.  She emphasized that the fundamental design change with edge that allowed the IV concept was moving the structural elements of the ship to the interior. I believe it was the Edge press event.

 

Edit....  Found the Video   jump to 34:40 for the relevant part

Edited January 24, 2019 by mnocket

[C-Dragons]

5 hours ago, justcrusn said:

The worst night EVER for us was on Reflection.

The ship creaked and squeaked so much we could not sleep.

Now, this was very heavy seas but still, some ship noise is not unheard of.

Same here. The creaking and squeaking was in a Signature suite and went on for days as we crossed the Atlantic.

[Orator]

At my age I'm creaking all the time. Must be an engineering flaw.

[ipeeinthepool]

1 minute ago, Orator said:

At my age I'm creaking all the time. Must be an engineering flaw.

 

And your out of warranty

[chemmo]

12 minutes ago, Orator said:

At my age I'm creaking all the time. Must be an engineering flaw.

 

It isn’t the age it is the mileage....

[kwokpot]

11 hours ago, Host Jazzbeau said:

Sailing on Edge right now and noticing that this ship has more creaks and groans – even in calm seas – than any other ship we have sailed on.  Caveat: I am not an engineer, and I hope that chengkp75 will set me straight on this thread straight off!  But I am wondering whether the 'breakthrough' engineering concept behind Celebrity Edge is fundamentally flawed.

 

Here is my non-engineer idea.  Back in the day cars were built as body-on-frame, which was cheap but led to flexing; Detroit finally came around to the European concept of monocoque which makes the outer skin a structural part and allows cars to be much more rigid.  Ships, on the other hand, have always been basically monocoque in design – the outer hull is a major structural component.

 

Celebrity Edge, if my concept holds, is more like a body-on-frame design.  The main structural components were moved inside to the corridor walls, making the entire cabin area a non-stressed external part of the ship.  This allowed the 'infinite veranda' cabins – but it also means that the cabins are much less solid-feeling than on a traditional ship.

 

If Edge flexes as much as I'm experiencing tonight – in calm seas – what will it be like in heavy seas?  [PS – I don't plan to find out.]

On my Dec. 16th sailing I would have to say it was one of the calmest and quietest sailings I've ever been on. I never heard any squeaks or rattles from my IV cabin #6154 and although we had neighbors on either side of us AND our cabin was a connected one with a door connecting to the cabin on the right we NEVER heard any noise from either side. 

Sailaways were equally smooth and TBH I never knew we had started sailing until I saw the scenery changing. In other words your experience with creaks and rattle is not universal on the Edge.

 

Edited January 24, 2019 by kwokpot

[DYKWIA]

6 hours ago, CeleryCruiser said:

I suppose that I know what you are trying to explain:  its like driving with BMW and comparing the experience with Peugeot....

 

Recently sold a lovely Lexus - that was a car that didn't creek once in 4 years for a BMW  - within 2 days realised I'd made a big mistake.  BMW are really nothing special (for the price they charge) and certainly not as good as the Pinafarina designed Peugeot my friend used to have.  Can't wait to get shut of it.

 

 

[TexSea]

12 hours ago, Host Jazzbeau said:

Sailing on Edge right now and noticing that this ship has more creaks and groans – even in calm seas – than any other ship we have sailed on.  Caveat: I am not an engineer, and I hope that chengkp75 will set me straight on this thread straight off!  But I am wondering whether the 'breakthrough' engineering concept behind Celebrity Edge is fundamentally flawed.

 

We were on the January 13th Edge cruise I remarked that it was the quietest and smoothest sailing I've ever been on. We were in SS 10205 with the solid wall IV next to us. But from what I'm reading, our week was a bit smoother than yours has been.

 

We were on Reflection in it's third month and we heard quite a bit of creaking then.

[C-Dragons]

1 hour ago, Orator said:

At my age I'm creaking all the time. Must be an engineering flaw.

Maybe you just need a “tune up”. 😁

[shipshapertoo]

2 hours ago, TexSea said:

We were on the January 13th Edge cruise I remarked that it was the quietest and smoothest sailing I've ever been on. We were in SS 10205 with the solid wall IV next to us. But from what I'm reading, our week was a bit smoother than yours has been.

 

We were on Reflection in it's third month and we heard quite a bit of creaking then.

I was also on the Jan 13 Edge sailing. IV cabin 8251. Smoothest sailing ever. No creaks, no groans. Sometimes I forgot I was on a ship when I was out and about on the ship until I passed a window or went outside.

[TeeRick]

To Jazz’s point I have also noticed more creaks and noises the past few nights than I would have expected on a spanking new ship!

[hcat]

4 hours ago, mnocket said:

Yeah I remember the same video.  She emphasized that the fundamental design change with edge that allowed the IV concept was moving the structural elements of the ship to the interior. I believe it was the Edge press event.

 

Edit....  Found the Video   jump to 34:40 for the relevant part

Wow..you have good retrieval skills! I knew I saw that someplace.

We have been on ships where we had to duct tape drawers closed, tied hangers together to stop clacking,..And many ships seem to have have a natural ceiling creak.

 

If the ship creaks I'm okay with it as long as it is safe.

( sounds paranoid but  I recall that the WT Center in NYC  also had a unique structure..caved like a pancake when struck)

[GoodScout]

I watched a video on how S-Class ships were built while onboard. Amazingly, they're assembled in giant blocks (sometimes 8 decks high and including 40-60 cabins at a time. This allows them to build the ships faster. Then the blocks are assembled and welded together. If you take the behinds the scenes tour and walk down I-95 (the main crew corridor) you can actually see the weld lines where the blocks were connected. 

 

Don't know if Edge was built in a different way by STX, but if you're onboard you can go to On Demand video in your room and watch the documentary for free. 

[kearney]

I remember early reports of noise after the ship left the ship yard, but never heard what the cause was.  I did not notice any particular creaking during our sailing. I do wonder if the windows might make some noise from flexing... River boats have similar windows but I am not sure that they are subjected to the same stresses as an ocean voyaging ship.... 

[chengkp75]

1 hour ago, GoodScout said:

I watched a video on how S-Class ships were built while onboard. Amazingly, they're assembled in giant blocks (sometimes 8 decks high and including 40-60 cabins at a time. This allows them to build the ships faster. Then the blocks are assembled and welded together. If you take the behinds the scenes tour and walk down I-95 (the main crew corridor) you can actually see the weld lines where the blocks were connected. 

 

Don't know if Edge was built in a different way by STX, but if you're onboard you can go to On Demand video in your room and watch the documentary for free. 

Virtually every ship built in the last 25 years has been built on the block/grand block method.  You build a block of about 25-30 tons on the ground, and then these blocks are assembled into "grand blocks" which will weigh 300-500 tons, depending on the shipyard's crane capacity, and the grand blocks are lowered into the drydock for assembly onto the ship.  Not all welds are from block/grand block joins.  Even within a block, some areas are too long for a standard sheet of steel, so there will be butt joints welded together.  Typically, my experience has been that the actual cabins are not installed in the grand blocks, but are all wheeled in once the entire section of deck is completed.

[ecslady]

6 hours ago, mnocket said:

Yeah I remember the same video.  She emphasized that the fundamental design change with edge that allowed the IV concept was moving the structural elements of the ship to the interior. I believe it was the Edge press event.

 

Edit....  Found the Video   jump to 34:40 for the relevant part

 

Thanks for reposting the link to that video.  Now that I have sailed on the EDGE, it was great to rewatch it. And the funniest moment is when Nate, one of the designers, calls it a "boat", and LLP has to correct him, it is a "ship".