Seasickness and Stabilizers

[kruisey]

 Have traveled many times  over the years in different weather conditions with Princess and was seasick once.This last year traveled twice first on Royal  Los Angeles via San Diego to Vancouver BC  no seasickness at all.Then boarded Star and first day out of Vancouver Hawaii return was violently seasick so bad that medical put me ahead of line up because I was wooping it up.  Then debarking day in Vancouver harbor I was in the washroom  again wooping up.

Do the stabilizers on the older ships weaken in time.Or is it the new technology on the new ship that my stomach tolerates better?,

[Pstcrik]

11 minutes ago, kruisey said:

 Have traveled many times  over the years in different weather conditions with Princess and was seasick once.This last year traveled twice first on Royal  Los Angeles via San Diego to Vancouver BC  no seasickness at all.Then boarded Star and first day out of Vancouver Hawaii return was violently seasick so bad that medical put me ahead of line up because I was wooping it up.  Then debarking day in Vancouver harbor I was in the washroom  again wooping up.

Do the stabilizers on the older ships weaken in time.Or is it the new technology on the new ship that my stomach tolerates better?,

 

[Pstcrik]

I think it is just us that weakens over time.

 

 

[Cruise Raider]

I've oftentimes thought that the older ships in the Princess fleet (Grand and even Crown class) are a lot less stable than their newer ships (Royal class).  

Some of it is just our body's tolerance at the time ... but, more likely it is the motion of the ocean and the ship's inability to handle it with such ease on the smaller ship.  

[Colo Cruiser]

39 minutes ago, kruisey said:

 Have traveled many times  over the years in different weather conditions with Princess and was seasick once.This last year traveled twice first on Royal  Los Angeles via San Diego to Vancouver BC  no seasickness at all.Then boarded Star and first day out of Vancouver Hawaii return was violently seasick so bad that medical put me ahead of line up because I was wooping it up.  Then debarking day in Vancouver harbor I was in the washroom  again wooping up.

Do the stabilizers on the older ships weaken in time.Or is it the new technology on the new ship that my stomach tolerates better?,

Stabilizers are rarely used. 
They don’t change over time as the premise is the same.
Technology is basically the same.

It also depends on the body at the time. Even crew who sail for years in all kinds of conditions can get sick one time and not under the same conditions next time.

[ALWAYS CRUZIN]

"Then debarking day in Vancouver harbor I was in the washroom  again wooping up" You were in port?

[kruisey]

1 minute ago, twodaywonder said:

"Then debarking day in Vancouver harbor I was in the washroom  again wooping up" You were in port?

We were in port but not anchored yet.

 

[kruisey]

All I know is that injection they give one in the medical is worth the money for after my wheelchair back to cabin and a little sleep I was in heaven again felt so good and HUNGRY.

 

[ALWAYS CRUZIN]

7 minutes ago, kruisey said:

We were in port but not anchored yet.

 

So the ship was very stable and not rocking.

[ALWAYS CRUZIN]

I never get sea sick to the point of throwing up. Sometimes uneasy. The last cruise on the Sky Princess the seas the first two days were really bad. Wife got sick in the middle of the night. Yes it went in the toilet. Got dressed and went to get here crackers and gingerale. Had her take a Tums. All settled down for her in about an hour. many years ago she would get sea sick easily. She beat it real good. I give her a lot of credit. Last time she got sea sick was about 20 years ago in the ships store. Things were falling off the shelves. If you easily get sea sick. DO NOT go on a glass bottom boat.

[riffatsea]

DH and I are very prone to seasickness but we have NEVER felt sick while in port or just docking!

Perhaps you had a virus and not just motion sickness?

[TheRabbit]

Royal class is a much larger and heavier class of ship and as such will not pitch and roll as easily and the moment might be longer. 

I have always wondered if they could apply a hydrodynamic model to get ahead of the pitch and roll. No matter what, the stabilizers to add drag and thus the mileage goes down.

[Colo Cruiser]

12 minutes ago, TheRabbit said:

Royal class is a much larger and heavier class of ship and as such will not pitch and roll as easily and the moment might be longer. 

I have always wondered if they could apply a hydrodynamic model to get ahead of the pitch and roll. No matter what, the stabilizers to add drag and thus the mileage goes down.

That’s what I thought but on the Sky TA not so much.

[ALWAYS CRUZIN]

Jan 11 on the Sky. Really rough seas the first few days. it pitched back and forth a lot. Only the drunks were walkin straight. BTY. If you want your coat hangers to stop making noise while trying to sleep in the rough seas. Do what I did. No noise at all the second day. Wish I would ahve thought of it the first night.

[chengkp75]

21 minutes ago, TheRabbit said:

I have always wondered if they could apply a hydrodynamic model to get ahead of the pitch and roll. No matter what, the stabilizers to add drag and thus the mileage goes down.

Not sure what you mean by a "hydrodynamic model", but stabilizers require a certain amount of roll to react to.  Actually, a taller ship will have a more violent, quicker rolling motion, since the center of gravity is higher.  Pitching is an uncontrolled motion, there is nothing that stabilizers can do about pitching.  And, pitching is determined by the wave period, bow design,  ship speed, and ship length.  Stabilizers do not really "reduce" rolling, they are designed to change the "period" (or speed) of the roll (dampen it), to be more comfortable and not a "snap" roll.

Edited January 26, 2020 by chengkp75

[TheRabbit]

1 hour ago, chengkp75 said:

Not sure what you mean by a "hydrodynamic model", but stabilizers require a certain amount of roll to react to.  Actually, a taller ship will have a more violent, quicker rolling motion, since the center of gravity is higher.  Pitching is an uncontrolled motion, there is nothing that stabilizers can do about pitching.  And, pitching is determined by the wave period, bow design,  ship speed, and ship length.  Stabilizers do not really "reduce" rolling, they are designed to change the "period" (or speed) of the roll (dampen it), to be more comfortable and not a "snap" roll.

Coming from aerospace where we worked control laws to dampen all three axes of movement. The idea of using some of this type of engineering (aerodynamics in water) to "anticipate" the change of motion to get ahead of it, in my mind, just might be achievable. As to pitch, the stabilizers do rotate, as such, some, though not much, pitch control could be added. I believe the systems today use an inertial to drive the stabilizers not control laws (per a few Princess captains I have spoken to), but I do not know nor can I find enough info to determine the validity of my premise of using control laws to get ahead of the motion and thus dampen it.

From personal observation, it appears the stabilizers, though deployed, are not activated until the roll or roll moment exceeds some limit. I have notice an immediate damping of the roll magnitude under these situations.

One of the limiting elements of doing this is the amount of force the equipment can sustain. Another piece of info I could never find.

I think I know what you mean by snap roll, but I have never experienced this. 

[chengkp75]

3 minutes ago, TheRabbit said:

Coming from aerospace where we worked control laws to dampen all three axes of movement. The idea of using some of this type of engineering (aerodynamics in water) to "anticipate" the change of motion to get ahead of it, in my mind, just might be achievable. As to pitch, the stabilizers do rotate, as such, some, though not much, pitch control could be added. I believe the systems today use an inertial to drive the stabilizers not control laws (per a few Princess captains I have spoken to), but I do not know nor can I find enough info to determine the validity of my premise of using control laws to get ahead of the motion and thus dampen it.

From personal observation, it appears the stabilizers, though deployed, are not activated until the roll or roll moment exceeds some limit. I have notice an immediate damping of the roll magnitude under these situations.

One of the limiting elements of doing this is the amount of force the equipment can sustain. Another piece of info I could never find.

I think I know what you mean by snap roll, but I have never experienced this. 

Had no idea of what "control laws" were, but after a quick search, I believe you are talking about PID controllers, which are common in maritime control systems, and are what stabilizers use.  The most common type of roll sensor used in stabilizers is a clinometer and vertical reference unit, but the latest are MRU's (motion reference units) that use solid state gyros and accelerometers.

 

I believe that you are feeling a reduction in roll "period" and not in roll "magnitude".  The size of the stabilizer in comparison to the size and weight of the ship, the stabilizer cannot hope to reduce the magnitude of the roll, which is determined by the wave force and the dynamic stability of the ship (the "GM" or metacentric height).  All the stabilizer can hope to do is to add some roll force in opposite direction to the hull, but at a different "time" (the stabilizer roll force is out of synchronization to the hull roll force), to lengthen the period of the roll.  Ships with a very high center of gravity compared to the center of buoyancy, tend to be "stiff", meaning it takes a lot of force to get the ship to start rolling, but that as soon as it starts to roll, the massive righting arm created by the high GM quickly tries to return the ship to upright, causing a short, very quick, and sudden rolling motion.  Cruise ships without stabilizers tend to be very stiff ships.  Ships with a very low center of gravity compared to the center of buoyancy, like a loaded tanker, are considered "tender", meaning that it does not take much to get the ship rolling, and there is not much righting arm, so the ship rolls more (magnitude) and slower, and frequently even hangs for a few seconds at the end of the roll, before starting to roll back the other way.  Tender ships roll more often, but the motion is far more comfortable than a stiff ship's snap rolling.  Stabilizers try to change a stiff ship into a more tender ship, to keep the motion comfortable.  There is, of course, some deadband, and proportional band in the stabilizer control, so it would need some roll to initiate control, each type of sensor having unique characteristics of dead band and proportional band.

 

As for pitch, again, given the width (front to back) of the stabilizer compared to the length of the ship, and the force generated by rotation of the airfoil of the stabilizer, is minimal.  The rotation of the stabilizer airfoil creates some "lift" as an aileron does on a plane, and this affects roll far more than pitch.

 

Not sure how you would "anticipate" a roll.

[kruisey]

It was a 15 day cruise Vancouver Hawaii and return   on Star Princess.

First day at sea had breakfast,it was rocky. Sitting at back of Princess theater around 9.00 AM lecture on Hawaii in the disabled section at the back for I have a mobility issue.All of a sudden I felt nauseated and went to the nearest washroom  that was the start no advance warning.

Edited January 27, 2020 by kruisey
Addition

[TheRabbit]

38 minutes ago, chengkp75 said:

Had no idea of what "control laws" were, but after a quick search, I believe you are talking about PID controllers, which are common in maritime control systems, and are what stabilizers use.  The most common type of roll sensor used in stabilizers is a clinometer and vertical reference unit, but the latest are MRU's (motion reference units) that use solid state gyros and accelerometers.

 

I believe that you are feeling a reduction in roll "period" and not in roll "magnitude".  The size of the stabilizer in comparison to the size and weight of the ship, the stabilizer cannot hope to reduce the magnitude of the roll, which is determined by the wave force and the dynamic stability of the ship (the "GM" or metacentric height).  All the stabilizer can hope to do is to add some roll force in opposite direction to the hull, but at a different "time" (the stabilizer roll force is out of synchronization to the hull roll force), to lengthen the period of the roll.  Ships with a very high center of gravity compared to the center of buoyancy, tend to be "stiff", meaning it takes a lot of force to get the ship to start rolling, but that as soon as it starts to roll, the massive righting arm created by the high GM quickly tries to return the ship to upright, causing a short, very quick, and sudden rolling motion.  Cruise ships without stabilizers tend to be very stiff ships.  Ships with a very low center of gravity compared to the center of buoyancy, like a loaded tanker, are considered "tender", meaning that it does not take much to get the ship rolling, and there is not much righting arm, so the ship rolls more (magnitude) and slower, and frequently even hangs for a few seconds at the end of the roll, before starting to roll back the other way.  Tender ships roll more often, but the motion is far more comfortable than a stiff ship's snap rolling.  Stabilizers try to change a stiff ship into a more tender ship, to keep the motion comfortable.  There is, of course, some deadband, and proportional band in the stabilizer control, so it would need some roll to initiate control, each type of sensor having unique characteristics of dead band and proportional band.

 

As for pitch, again, given the width (front to back) of the stabilizer compared to the length of the ship, and the force generated by rotation of the airfoil of the stabilizer, is minimal.  The rotation of the stabilizer airfoil creates some "lift" as an aileron does on a plane, and this affects roll far more than pitch.

 

Not sure how you would "anticipate" a roll.

My use of control laws in in reference to the mathematical model that allows an unstable plat form to fly. Many modern aircraft can't fly with out it. In this case it would be a mathematical model of of the ships behavior relative to the seas, then using sensors to measure the next wave's direction and magnitude, adjust accordingly.

What I mean by "Anticipate" is the rolling of a ship to a point of switching directions. I would think in theory they could change the stabilizer setting just a bit sooner to get a bit more ahead of the force. See above.

 

Taking off for dinner, will go through what you said a little closer tomorrow.

[ram290]

Always play it safe.  Motion patches or Dramamine.

No one ever wants to get sick if it is preventable!

[kruisey]

It was reported I just remembered they said ship was rocking side to side instead of to and fro

[WisCruiser2]

7 hours ago, kruisey said:

It was reported I just remembered they said ship was rocking side to side instead of to and fro

The couple of times I've had seasickness was when the ship was rolling side to side, the bow to aft motion doesn't seem to bother me. Fortunately it's never been to the point of vomiting but I just had to lie down for several hours. The only saving thing with it is that when it's over, it's over!

[BigGuy25]

On 1/26/2020 at 3:09 PM, twodaywonder said:

Jan 11 on the Sky. Really rough seas the first few days. it pitched back and forth a lot. Only the drunks were walkin straight. BTY. If you want your coat hangers to stop making noise while trying to sleep in the rough seas. Do what I did. No noise at all the second day. Wish I would ahve thought of it the first night.

We’ve been on many cruises and never thought of the towel trick for the hangers.  I always just spread them out ... but that doesn’t always work well. Thanks for teaching this old dog a new trick!!

[Homosassa]

While pitch and roll ans been talked about, let's not forget yaw that stabilizers do nothing to prevent.

[Anubi]

I also get seasick.  We did Hawaii out of SFO last year and I went down early on the first night but felt fine by mid-morning the next day.  On the return, it was rough on the last day. 

 

FWIW I was told that the stabilizers only work on side-to-side rolling.  Once the ship starts with the nose down and back end up and then nose up and back end down (can't think of the proper term LOL) there is nothing that can be done,.  One interesting thing of note, for me anyway, the larger the ship the worse my problem seems.  With most people its the other way.