Aircraft Carriers stability

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chrisclin

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While scorching past Rosyth against the tide the other day, I had the opportunity of a long look at the pride of Gordon Brown's Navy which is suddenly beginning to become recognisable. The Islands are now sprouting on the Starboard side and I started wondering how they are balanced. Each of them were quoted as being several hundred tons when they left the Clyde and they sit a long way off the centre line.
Anyone know?
 
Chris,

they're simply balanced by seawater ballast tanks usually but there will be active stabiliser systems as well.

If you look at WWII pics of carriers they often had a slight list to starboard.
 
chrisclin said:
The Islands are now sprouting on the Starboard side and I started wondering how they are balanced.
Anyone know?
Click to expand...

Unfortunately Gordon Brown didn't bother balancing anything when he made the decision to award those contracts.

I thoroughly support the Armed Forces as a former soldier, I thoroughly support the RN as a keen sailor, and I thoroughly support the FAA as a professional pilot - but those carriers are not the best way to spend our limited defence budget for the future threats that we may face.
 
chrisclin said:
While scorching past Rosyth against the tide the other day, I had the opportunity of a long look at the pride of Gordon Brown's Navy which is suddenly beginning to become recognisable. The Islands are now sprouting on the Starboard side and I started wondering how they are balanced. Each of them were quoted as being several hundred tons when they left the Clyde and they sit a long way off the centre line.
Anyone know?
Click to expand...

By the Flight deck on the other side
 
Seajet said:
Chris,

they're simply balanced by seawater ballast tanks usually but there will be active stabiliser systems as well.

If you look at WWII pics of carriers they often had a slight list to starboard.
Click to expand...

Ballast tanks is the right answer.

HMS OCEAN (our biggest ship and a Helicopter Carrier) has huge ballast tanks on the port side to counter balance the weight of the island.

In the pictures of WWII carriers, my strong suspicion is that if there was ever a 'slight list; it would have been a mistake or a feature of circumstances. (The ship turning perhaps?)

Trim and ballast is adjusted all the time on a modern warship. The stabilisers are there for the weapons systems and not for the comfort of the crew!
 
Woodlouse said:
One would imagine that there is plenty of heavy gear that needs building into a carrier that they can stick in the port side of the hull rather than just rely on water ballast.
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I didn't say what was in the ballast tanks! I was going to explain a bit more, but we are now constantly being reminded at work to say factual and non controversial things on social media etc Also every bit of information is likely to be gathered and pieced together so I thought I'd keep it brief.

Of course we don't do such things with information one gleans from other foreign powers...
 
john_morris_uk said:
I didn't say what was in the ballast tanks! I was going to explain a bit more, but we are now constantly being reminded at work to say factual and non controversial things on social media etc Also every bit of information is likely to be gathered and pieced together so I thought I'd keep it brief.

Of course we don't do such things with information one gleans from other foreign powers...
Click to expand...
Ah, course, I guess if the fuel tanks are there then they can be flooded once empty with no unnecessary loss of space.
 
chrisclin said:
While scorching past Rosyth against the tide the other day, I had the opportunity of a long look at the pride of Gordon Brown's Navy which is suddenly beginning to become recognisable. The Islands are now sprouting on the Starboard side and I started wondering how they are balanced. Each of them were quoted as being several hundred tons when they left the Clyde and they sit a long way off the centre line.
Anyone know?
Click to expand...

I shouldn't concern yourself overduely, at the rate we're going, (cutbacks, redundancies, etc.) A, there wont be anyone to man it, B, we (as a country) can't afford to put aircraft on it, C, contrary to popular belief Britannia no longer rules the waves.
 
Interesting thread and something I'd thought about before. They also look very top heavy much like cruise ships always do!

One other kinda related thought I had once (when fitting an outboard) concerned the offset used to counter prop steer on single drive vessels. I couldn't help wonder if the drive shaft of a sub was offset by an inch or two? It is after all a very large prop and must have a significant steering effect - I've not noticed any fitted with duoprops...:rolleyes:
 
rbcoomer said:
Interesting thread and something I'd thought about before. They also look very top heavy much like cruise ships always do!

One other kinda related thought I had once (when fitting an outboard) concerned the offset used to counter prop steer on single drive vessels. I couldn't help wonder if the drive shaft of a sub was offset by an inch or two? It is after all a very large prop and must have a significant steering effect - I've not noticed any fitted with duoprops...:rolleyes:
Click to expand...

http://www.submarineresearch.com/bull70.html
 
Ric said:
Unfortunately Gordon Brown didn't bother balancing anything when he made the decision to award those contracts.

I thoroughly support the Armed Forces as a former soldier, I thoroughly support the RN as a keen sailor, and I thoroughly support the FAA as a professional pilot - but those carriers are not the best way to spend our limited defence budget for the future threats that we may face.
Click to expand...

Stick with Trident you mean? ;)
 
capnsensible said:
http://www.submarineresearch.com/bull70.html
Click to expand...

Fascinating stuff, doesn't mention if the drive train is usually offset an inch or two however! :) I had seen the 'prop guard' type ring and assumed it was to do with noise. Quite surprised the prop has never moved either inside or alongside the hull - similar to jet designs or better still imitated fish...

Sorry for 'Fred Drift'.
 
rbcoomer said:
Fascinating stuff, doesn't mention if the drive train is usually offset an inch or two however! :) I had seen the 'prop guard' type ring and assumed it was to do with noise. Quite surprised the prop has never moved either inside or alongside the hull - similar to jet designs or better still imitated fish...

Sorry for 'Fred Drift'.
Click to expand...

It is not offset.
 
rbcoomer said:
Fascinating stuff, doesn't mention if the drive train is usually offset an inch or two however! :) I had seen the 'prop guard' type ring and assumed it was to do with noise. Quite surprised the prop has never moved either inside or alongside the hull - similar to jet designs or better still imitated fish...

Sorry for 'Fred Drift'.
Click to expand...

You have to remember that a submarine uses quite a lot of horsepower to get around which means that you have quite a few considerations for structural strength when you move away from the normal shaft driven propulsor. Alternative arrangements typically weigh more and that generates weight problems. As for torque rotating the hull I never noticed it and doing my time in SSN03 we were still doing first of class type trials on handling. You also have to remember that a boat has quite a few horizontal and vertical control surfaces which do react against torque You still get prop walk though
 
Early SSNs could plane on the surface. Was called going on the 'step'. By venting the aft ballast tanks, selecting big revs and doing a bit of a wiggle, the submarine would effectively get on its own bow wave and crank along at impressive speed.

It was somewhat interesting inside....

Avalook at 1 minute and a few seconds:

http://www.youtube.com/watch?v=dagIxWjoWa4&feature=player_embedded

Hope this is of interest.
 
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