ESCAPE Technical Q&A regarding Motion

[BMH5150]

I attended the Technical Q&A session on the FEB-20th cruise. I found it to be very informational and fascinating. Although I'm left very curious to know what is really going on regarding the added "movement" that is felt on this ship as compared to other cruise ships of similar sizes.

 

As I read many reviews on here and on other sites and social media (that I wont mention) it's a common experience to feel a little extra motion on the Escape. While this motion didn't bother me in the least...and I'm easily prone to motion sickness and have gotten sick on several ships...I felt it too, but didn't get sick at all.

 

What I find curious is that there are several different answers and opinions as to why there is a little extra motion felt on the Escape. I'm even reading that the captain is answering this commonly asked question differently at his weekly Technical Q&A sessions. At my Q&A his response was "the bigger the ship...the more movement is felt" at a different Q&A his response was that the ocean is a little rough at this time of the year. Yet, this motion has been felt and reported by almost everyone that has written a review about the Escape.

 

What is the latest on this? I'm not a nautical engineer but it does seem plausible that a larger ship might be susceptible to motion simply because it's larger and will capture more wind and movement...I don't know...I'm just very curious because I've also read that there are issues with the stabilizers. If there are issues with the stabilizers I can see why the captain might want to avoid answering this question or give a different answer each time to avoid panic.

 

I'm only curious...we loved the Escape and this isn't a negative review by any means. We are already booked for another cruise on the Escape in December!

 

Does anyone have any insight on this?

 

Brian

[UKLloyd]

I attended the Technical Q&A session on the FEB-20th cruise. I found it to be very informational and fascinating. Although I'm left very curious to know what is really going on regarding the added "movement" that is felt on this ship as compared to other cruise ships of similar sizes.

 

As I read many reviews on here and on other sites and social media (that I wont mention) it's a common experience to feel a little extra motion on the Escape. While this motion didn't bother me in the least...and I'm easily prone to motion sickness and have gotten sick on several ships...I felt it too, but didn't get sick at all.

 

What I find curious is that there are several different answers and opinions as to why there is a little extra motion felt on the Escape. I'm even reading that the captain is answering this commonly asked question differently at his weekly Technical Q&A sessions. At my Q&A his response was "the bigger the ship...the more movement is felt" at a different Q&A his response was that the ocean is a little rough at this time of the year. Yet, this motion has been felt and reported by almost everyone that has written a review about the Escape.

 

What is the latest on this? I'm not a nautical engineer but it does seem plausible that a larger ship might be susceptible to motion simply because it's larger and will capture more wind and movement...I don't know...I'm just very curious because I've also read that there are issues with the stabilizers. If there are issues with the stabilizers I can see why the captain might want to avoid answering this question or give a different answer each time to avoid panic.

 

I'm only curious...we loved the Escape and this isn't a negative review by any means. We are already booked for another cruise on the Escape in December!

 

Does anyone have any insight on this?

 

Brian

 

I am not an expert at all, However, Surely the bigger the ship the more movement there is, Is wrong? I have been on the Oasis of the seas, at one point, We didnt even realise we had left port, no movement at all. Then on the Getaway, the movement could definatly be felt. Didnt feel any movement on the Epic either. All ships were in calm seas as well.

[chengkp75]

Well, yes and no to the "bigger the ship the more it moves" theory. Size really doesn't factor into stability, or the ship's ability to stay upright and resist rolling. However, the ship does roll around a "pivot" point that is fairly low in the ship, so the more decks a ship has, hence the higher it is, the upper decks will move more lateral feet for the same angle of roll.

 

Cruise ships are designed to find a balance between very "high" stability which makes the ship difficult to roll over, but which has a very quick roll period which is uncomfortable, and "low" stability which produces a slow, comfortable roll, but which is easier to roll over.

 

Now, there is also the difference between rolling and heeling. A larger ship will heel over (stay at a particular angle off the vertical) due to the sail area of the superstructure being acted on by the wind. Rolling is caused by waves, and is dependent on the relationship between the center of buoyancy and the center of gravity, not so much the gross size or shape of the ship.

 

I don't believe there are "issues" with the stabilizers. However, not knowing the route or itinerary, there are factors that make the stabilizers less effective. First off, they are more like airplane wings than anything else, so they require adequate water flow over the stabilizer to create "lift" on the stab which is then transmitted to the hull to "lift" that side against the roll. The slower the ship goes, and given today's slow steaming itineraries, I would say this happens a lot, the less effective the stab is, until around 6 knots they are completely ineffective, and will generally self-retract at that speed.

 

What exactly, is the motion you feel is greater on Escape? Rolling, pitching, yawing, vibration, or the "cruise ship shimmy" (sort of a side to side shaking, most noticeably at the after part of the ship?

[moggin123]

Honestly it makes sense that the escape will have more motion felt than oasis with royal, the designs of the ships are extremely different. The escapes max beam length (across) is only 136 ft, and 22 decks i believe, while the oasis is 216 ft max beam length while 18 decks high. Of course even though both are large ships, the shorter, brooder base of oasis will definitely give it more stability then is provided on the escape.

 

think of when you played with legos, or built sand castles as a kid, you could make one with a very small base and try to build it up, and one with a larger base and make it the same hight, the larger base will hold up better against tough conditions.

 

Obviously the escape was built to standards that it will not fail, but to compare those two ships is pretty tough due to such a large design difference. the structural aspect of oasis does seem to be more desirable. I went on oasis a few years ago and felt more motion on that ship than i did on more 'medium' sized ships. I will be on escape next week.

[chengkp75]

Honestly it makes sense that the escape will have more motion felt than oasis with royal, the designs of the ships are extremely different. The escapes max beam length (across) is only 136 ft, and 22 decks i believe, while the oasis is 216 ft max beam length while 18 decks high. Of course even though both are large ships, the shorter, brooder base of oasis will definitely give it more stability then is provided on the escape.

 

think of when you played with legos, or built sand castles as a kid, you could make one with a very small base and try to build it up, and one with a larger base and make it the same hight, the larger base will hold up better against tough conditions.

 

Obviously the escape was built to standards that it will not fail, but to compare those two ships is pretty tough due to such a large design difference. the structural aspect of oasis does seem to be more desirable. I went on oasis a few years ago and felt more motion on that ship than i did on more 'medium' sized ships. I will be on escape next week.

 

It's not quite a drastic difference as you state. While the Oasis class has a "max beam" of 198' (not 215') that is at the widest possible two points, in Oasis' case, from outside of the lifeboat to outside of the lifeboat, or bridge wing to wing. Her beam at the waterline is 154' to Escape's 136'. I have not seen a figure for Escape's max beam, but her lifeboats hang outboard as well, and the bridge wings are wide as well. Given the difference in gross tonnage and displacement, this is not a significant difference with regards to stability.

[BMH5150]

Well, yes and no to the "bigger the ship the more it moves" theory. Size really doesn't factor into stability, or the ship's ability to stay upright and resist rolling. However, the ship does roll around a "pivot" point that is fairly low in the ship, so the more decks a ship has, hence the higher it is, the upper decks will move more lateral feet for the same angle of roll.

 

Cruise ships are designed to find a balance between very "high" stability which makes the ship difficult to roll over, but which has a very quick roll period which is uncomfortable, and "low" stability which produces a slow, comfortable roll, but which is easier to roll over.

 

Now, there is also the difference between rolling and heeling. A larger ship will heel over (stay at a particular angle off the vertical) due to the sail area of the superstructure being acted on by the wind. Rolling is caused by waves, and is dependent on the relationship between the center of buoyancy and the center of gravity, not so much the gross size or shape of the ship.

 

I don't believe there are "issues" with the stabilizers. However, not knowing the route or itinerary, there are factors that make the stabilizers less effective. First off, they are more like airplane wings than anything else, so they require adequate water flow over the stabilizer to create "lift" on the stab which is then transmitted to the hull to "lift" that side against the roll. The slower the ship goes, and given today's slow steaming itineraries, I would say this happens a lot, the less effective the stab is, until around 6 knots they are completely ineffective, and will generally self-retract at that speed.

 

What exactly, is the motion you feel is greater on Escape? Rolling, pitching, yawing, vibration, or the "cruise ship shimmy" (sort of a side to side shaking, most noticeably at the after part of the ship?

 

Very interesting!

 

I'd say it's more of the "cruise ship shimmy" but it isn't just me. There are a large number of reviews from people that have been on the Escape who have noticed this. I just find the topic interesting...especially after reading that the captain is answering his questions differently at the Technical Q&As. The theory of "the bigger the ship" was not my theory. It was the CAPTAIN's theory! If you could've been there to read his body language and see his in depth responses to the other questions as compared to this question...he reminded me of a politician that wanted to avoid the question. He acted as if he was on the hot seat. It was awkward.

 

It's amazing to me that these ships are even able to stay afloat!!

 

Brian

Edited March 7, 2016 by BMH5150

[chengkp75]

Very interesting!

 

I'd say it's more of the "cruise ship shimmy" but it isn't just me. There are a large number of reviews from people that have been on the Escape who have noticed this. I just find the topic interesting...especially after reading that the captain is answering his questions differently at the Technical Q&As. The theory of "the bigger the ship" was not my theory. It was the CAPTAIN's theory! If you could've been there to read his body language and see his in depth responses to the other questions as compared to this question...he reminded me of a politician that wanted to avoid the question. He acted as if he was on the hot seat. It was awkward.

 

It's amazing to me that these ships are even able to stay afloat!!

 

Brian

 

Some of it may have been seeing it as a complaint against his ship, and some may have been about trying not to get too technical.

 

The "shimmy" is endemic to ships with azipod propulsion, as they have a large, flat area of the hull above and aft of the pods, and the water flow from the pods tends to throw this back and forth, especially as the pods "steer" by pointing in slightly different directions to the length of the ship.

[bmaltais]

I was on the Escape last week and actually found it to be the calmest cruise ever from a ship move point of view. My wife actually complained that the ship was not rocking enough at night because she like the movement when she sleep...

[Biz64]

We were on the Feb 20th cruise on the Escape and it was the most motion I've felt on a ship before. It was from the moment we left Miami until we got back and it was all kids of motion, including vibration we noticed in the main dining rooms. We were on the Allure of The Seas last year and barely felt any motion. The motion doesn't really bother me, but you can really feel it. Even the water in the pool was splashing from side to side.

[BMH5150]

I was on the Escape last week and actually found it to be the calmest cruise ever from a ship move point of view. My wife actually complained that the ship was not rocking enough at night because she like the movement when she sleep...

 

I guess it's all a matter of opinion. I'm not a cruise ship expert but I don't seem to be the only one that has reported the extra movement felt on this ship compared to most ships of similar size.

 

I'm just curious to know if there technical reason for it.

[BMH5150]

We were on the Feb 20th cruise on the Escape and it was the most motion I've felt on a ship before. It was from the moment we left Miami until we got back and it was all kids of motion, including vibration we noticed in the main dining rooms. We were on the Allure of The Seas last year and barely felt any motion. The motion doesn't really bother me, but you can really feel it. Even the water in the pool was splashing from side to side.

 

Now that you mention it...I spent considerable time in the pool with my 4 year old son and we had the same experience. It was slightly annoying...and every time we were in the pool the water was side to side.