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How Do Stabilizers On Ships Work?  
User currently offlineUnited Airline From Hong Kong, joined Jan 2001, 9106 posts, RR: 15
Posted (5 years 5 months 3 weeks 2 days 21 hours ago) and read 18495 times:

How do stabilizers on ships work? Do they help a lot at rough seas?

35 replies: All unread, showing first 25:
 
User currently onlineDreadnought From United States of America, joined Feb 2008, 8709 posts, RR: 24
Reply 1, posted (5 years 5 months 3 weeks 2 days 21 hours ago) and read 18489 times:



Quoting United Airline (Thread starter):
How do stabilizers on ships work? Do they help a lot at rough seas?

They are gyroscopically operated, and help mostly with roll caused by medium sized seas. Really rough seas will definately overwhelm their capabilities.



Veni Vidi Castratavi Illegitimos
User currently offlineBristolFlyer From United Kingdom, joined May 2004, 2270 posts, RR: 0
Reply 2, posted (5 years 5 months 3 weeks 2 days 21 hours ago) and read 18472 times:

I know of 2 different types of stabilizers. Firstly, fins that stick out from the sides of the hull (underneath the waterline). They slow the boat rolling by making it harder for the hull to move through the water.

The second one was very simple, but simple os good. I saw it on a large (about 80') motor yacht. It was a 1-ton weight on a rail inside the engine bay, the rail was mounted across the boat. I believe hat other than being able to lock the weight in position, it wasn't powered - it only ever rolled 'downhill'. So the boat would roll to port, the weight would roll that way and counteract the boat rolling back to starboard so quickly.

After writing this I did a wki search for you:

http://en.wikipedia.org/wiki/Ship_stabilizer



Fortune favours the brave
User currently offlineAstuteman From United Kingdom, joined Jan 2005, 9834 posts, RR: 96
Reply 3, posted (5 years 5 months 3 weeks 2 days 21 hours ago) and read 18469 times:
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Quoting BristolFlyer (Reply 2):
The second one was very simple, but simple os good. I saw it on a large (about 80') motor yacht. It was a 1-ton weight on a rail inside the engine bay, the rail was mounted across the boat. I believe hat other than being able to lock the weight in position, it wasn't powered - it only ever rolled 'downhill'. So the boat would roll to port, the weight would roll that way and counteract the boat rolling back to starboard so quickly.

This is done with tanks of water on some bigger vessels, which are "tuned" to the natural frequency of the ship's motion......
Simple, and elegant..  Smile

Rgds


User currently offlineUnited Airline From Hong Kong, joined Jan 2001, 9106 posts, RR: 15
Reply 4, posted (5 years 5 months 3 weeks 2 days 19 hours ago) and read 18422 times:

Any pictures of it?

I was on Oceania Insignia around Cape Horn and it was very rough.

If I was on Grand Princess, Freedom of the seas or bigger ships will it be more stable?


User currently offlineEMBQA From United States of America, joined Oct 2003, 9364 posts, RR: 11
Reply 5, posted (5 years 5 months 3 weeks 2 days 18 hours ago) and read 18400 times:



Quoting United Airline (Reply 4):
Any pictures of it?

There are several different designs. Most common look like stabilizers on a plane. They stick out of the hull and adjust to reduce the roll...



"It's not the size of the dog in the fight, but the size of the fight in the dog"
User currently offlineDocLightning From United States of America, joined Nov 2005, 18676 posts, RR: 58
Reply 6, posted (5 years 5 months 3 weeks 2 days 18 hours ago) and read 18399 times:

There are two basic kinds, as has been said here.

The first are a set of fins that stick out of the side of the hull. They simply change their angle of attack just like a plane's stabilizer to counter the roll. They can reduce the ship's roll to essentially nothing.

The second type is a pair of tanks of water with a high-speed pump that pumps water between them to balance the ship against rolling. I've been on this sort of ship, too, and they roll more, but it still takes the bite out of the roll. We were also doing the Drake Passage...


User currently offlinePPVRA From Brazil, joined Nov 2004, 8873 posts, RR: 40
Reply 7, posted (5 years 5 months 3 weeks 2 days 18 hours ago) and read 18394 times:



Quoting United Airline (Reply 4):
If I was on Grand Princess, Freedom of the seas or bigger ships will it be more stable?

Bigger will always help. Bigger + stabilizers even better.



"If goods do not cross borders, soldiers will" - Frederic Bastiat
User currently offlineKlaus From Germany, joined Jul 2001, 21353 posts, RR: 54
Reply 8, posted (5 years 5 months 3 weeks 2 days 18 hours ago) and read 18384 times:

An image search has turned up these:

Extended:


Retracted:


User currently offlineSkidmarks From UK - England, joined Dec 2004, 7121 posts, RR: 58
Reply 9, posted (5 years 5 months 3 weeks 2 days 17 hours ago) and read 18371 times:

Whatever they do I recommend a trip on the Ben my Cree from Heysham to Douglas in the Isle of Man in a force 8 gale. There you will feel exactly what stabilisers are incapable of!!! Big grin

And be very sick into the bargain!  vomit 

Andy  old 



Growing old is compulsory, growing up is optional
User currently offlineDocLightning From United States of America, joined Nov 2005, 18676 posts, RR: 58
Reply 10, posted (5 years 5 months 3 weeks 2 days 17 hours ago) and read 18366 times:



Quoting Skidmarks (Reply 9):
Whatever they do I recommend a trip on the Ben my Cree from Heysham to Douglas in the Isle of Man in a force 8 gale. There you will feel exactly what stabilisers are incapable of!!! Big grin

And be very sick into the bargain! vomit

I made the Drake Passage without getting sick. Second day of the voyage I felt a bit "off" but I was faring a lot better than many of the Russian crew, who were walking into walls (admittedly at times the walls seemed more horizontal than the floors) and looking a bit green. Meanwhile, I just seem to be immune to motion sickness.


User currently offlineMCOflyer From United States of America, joined Jun 2006, 8625 posts, RR: 15
Reply 11, posted (5 years 5 months 3 weeks 2 days 17 hours ago) and read 18354 times:

You can have whats called Paravane roll Stabilizers. Heres a photo of one:

http://www.tsb.gc.ca/en/reports/marine/1998/m98n0064/photo_1.jpg

Note the outriggers on the side of the boat. When one side goes down or up the other helps keep the boat level. Another form of stabilization is the sea gyro used for boats from 5-50meters. Heres more information:

http://www.abc.net.au/tv/newinventors/txt/s1415189.htm

Hope this helps,
Hunter



Never be afraid to stand up for who you are.
User currently offlineComorin From United States of America, joined May 2005, 4868 posts, RR: 16
Reply 12, posted (5 years 5 months 3 weeks 2 days 15 hours ago) and read 18328 times:



Quoting United Airline (Reply 4):
If I was on Grand Princess, Freedom of the seas or bigger ships will it be more stable?

Even the biggest ships ( I was on the Monarch of The Seas), you can feel really tiny in a Hurricane! The force with which the ship smashes down on the waves, the groan of the steel beams, and the unsteady floors can be a truly terrifying experience even for hardened seamen. You keep waiting for the next wave, the bow of the ship rises, the rivets creak, and Bam!, the bow smashes into the trough, flooding the decks...it goes on interminably.

Stabilizers are great for damping rolling motion over normal range but are limited in their use in extreme pitching conditions.


User currently offlineDocLightning From United States of America, joined Nov 2005, 18676 posts, RR: 58
Reply 13, posted (5 years 5 months 3 weeks 2 days 15 hours ago) and read 18318 times:



Quoting Comorin (Reply 12):

Even the biggest ships ( I was on the Monarch of The Seas), you can feel really tiny in a Hurricane! The force with which the ship smashes down on the waves, the groan of the steel beams, and the unsteady floors can be a truly terrifying experience even for hardened seamen. You keep waiting for the next wave, the bow of the ship rises, the rivets creak, and Bam!, the bow smashes into the trough, flooding the decks...it goes on interminably.

And you sit there wondering if you're going to capsize or break in two.


User currently offlineBristolFlyer From United Kingdom, joined May 2004, 2270 posts, RR: 0
Reply 14, posted (5 years 5 months 3 weeks 2 days 14 hours ago) and read 18297 times:



Quoting MCOflyer (Reply 11):
You can have whats called Paravane roll Stabilizers. Heres a photo of one:

Huh, I thought those were for spreading fishing nets wide. I did a search and they have fin-like devices that cut throught the water beneath them.



Fortune favours the brave
User currently offlineMCOflyer From United States of America, joined Jun 2006, 8625 posts, RR: 15
Reply 15, posted (5 years 5 months 3 weeks 2 days 14 hours ago) and read 18289 times:



Quoting BristolFlyer (Reply 14):

Huh, I thought those were for spreading fishing nets wide. I did a search and they have fin-like devices that cut throught the water beneath them.

Heres more information:

http://www.kastenmarine.com/roll_attenuation.htm

Scroll down about halfway and you'll see the word "paravanes."

Hunter



Never be afraid to stand up for who you are.
User currently offlineUnited Airline From Hong Kong, joined Jan 2001, 9106 posts, RR: 15
Reply 16, posted (5 years 5 months 3 weeks 2 days 11 hours ago) and read 18239 times:



Quoting PPVRA (Reply 7):
Bigger will always help. Bigger + stabilizers even better.

How much of a difference between Grand Princess and Oceania Insignia at Cape Horn? It was really rough that time


User currently offlinePPVRA From Brazil, joined Nov 2004, 8873 posts, RR: 40
Reply 17, posted (5 years 5 months 3 weeks 2 days 10 hours ago) and read 18235 times:



Quoting United Airline (Reply 16):
Grand Princess

Seems not very easy to find data on MS Insignia, though from pictures, Grand Princess is MUCH larger.



"If goods do not cross borders, soldiers will" - Frederic Bastiat
User currently offlineComorin From United States of America, joined May 2005, 4868 posts, RR: 16
Reply 18, posted (5 years 5 months 3 weeks 2 days 10 hours ago) and read 18233 times:



Quoting DocLightning (Reply 13):
Quoting Comorin (Reply 12):

Even the biggest ships ( I was on the Monarch of The Seas), you can feel really tiny in a Hurricane! The force with which the ship smashes down on the waves, the groan of the steel beams, and the unsteady floors can be a truly terrifying experience even for hardened seamen. You keep waiting for the next wave, the bow of the ship rises, the rivets creak, and Bam!, the bow smashes into the trough, flooding the decks...it goes on interminably.

And you sit there wondering if you're going to capsize or break in two.

 yes 


User currently offlineUnited Airline From Hong Kong, joined Jan 2001, 9106 posts, RR: 15
Reply 19, posted (5 years 5 months 3 weeks 22 hours ago) and read 18108 times:

Do stabilizers help a lot even in very rough conditions?

User currently offlineDocLightning From United States of America, joined Nov 2005, 18676 posts, RR: 58
Reply 20, posted (5 years 5 months 3 weeks 19 hours ago) and read 18060 times:



Quoting United Airline (Reply 19):
Do stabilizers help a lot even in very rough conditions?

They decrease roll, which is the most uncomfortable motion just because of its frequency and magnitude. And they help a LOT. They do not, however, eliminate all sense of motion and they do nothing to decrease pitch.

But if a ship wants to pitch, let it pitch its heart content. It's roll that bugs me.


User currently offlineUnited Airline From Hong Kong, joined Jan 2001, 9106 posts, RR: 15
Reply 21, posted (5 years 5 months 3 weeks 11 hours ago) and read 18005 times:

Roll means left and right movements right?

User currently offlineSASD209 From British Indian Ocean Territory, joined Oct 2007, 640 posts, RR: 0
Reply 22, posted (5 years 5 months 3 weeks 7 hours ago) and read 17966 times:



Quoting United Airline (Reply 21):
Roll means left and right movements right?

Port and starboard, but yes. Through the longitudinal axis of the ship  Wink

Pitch is the fore and aft "up and down" motion of the vessel, usually as it encounters swells.

SASD209


User currently offlineVikkyvik From United States of America, joined Jul 2003, 9392 posts, RR: 27
Reply 23, posted (5 years 5 months 3 weeks 6 hours ago) and read 17963 times:
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Quoting Astuteman (Reply 3):
This is done with tanks of water on some bigger vessels, which are "tuned" to the natural frequency of the ship's motion......

Believe many skyscrapers have similar water tanks or other weights on their roofs, that also dampen the natural swaying of the building.

Quoting PPVRA (Reply 7):
Bigger will always help.

That's what she said  duck 



"Two and a Half Men" was filmed in front of a live ostrich.
User currently offlineUnited Airline From Hong Kong, joined Jan 2001, 9106 posts, RR: 15
Reply 24, posted (5 years 5 months 3 weeks 6 hours ago) and read 17958 times:

Up and down is ok. But left and right bothers me

25 Astuteman : Although size isn't everything.... Most modern cruise liners are inherently disadvantaged by having a large metacentric height as a result of the dra
26 Skidmarks : Obviously he doesnt travel on the "right" sort of ship!! Andy
27 DocLightning : Works a bit differently. Those weights are basically dampers that increase the mass of the building and this 1) lower its intrinsic frequency and 2)
28 Zkpilot : Try going on a Navy Frigate in the Southern Ocean at speed through 100ft ocean swells... the ship goes through the wave and is almost completely subme
29 Sprout5199 : I would have to disagree. The ship I was(FFG), rolled quite a bit, but didn't get too many people sick, but when we pitched a lot most of the crew wa
30 Post contains links MCOflyer : I would like to pics of this. Also, I know a couple who have a Sea Gyro on their vessel and love it. http://www.seagyro.com/ Hunter
31 Post contains images Zkpilot : Its been a while since I've seen those pics... just tried to find them but no luck... here are some other ones I have found online tho.. These waves
32 MarSciGuy : As other posters have said, yes bigger does help to some extent, but being you have to take into account where you are in relation to the vessels CG
33 C172Akula : Another survivor of the 'Drake Shake', I did it in February of this year on the way down to Antarctica. Let that ship pitch all it wants, but the rol
34 MarSciGuy : WOW!!!!!!!!!!!!!!!! 60 degrees! Why were you heading for Antarctica?
35 MCOflyer : The bottom photo looks like 30ft swells. Nice photos. If I ever own a a trawler, a Sea Gyro is going to be on order for stability. This is the stabil
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