Container ship "flexing" in heavy seas. Awesome sight below deck.

Not something you see everyday.

http://youtu.be/NE_ri8PkihE

 

Maybe it happens more than we think

http://www.boatdesign.net/forums/al...ear-old-container-ship-breaks-half-47373.html

 

Meehh, typical, and why ships are built of steel. Hogging or sagging a foot or two is common. On ore carriers you can actually see the hull girder troque in a cross seaway. This is why catwalks have expansion joints and transfer pipes on supertanker decks have relief bends.

Normal flexure of a structure has nothing to do with failure, as a ship will flex in a seaway. The failure occurs not because of the flexure, but because of design, fabrication, or material issues.

 

Well I'd never seen it happen before. Bet I'm not the only one too. Some of the comments under that YouTube vid mention how first time viewers react.

 

Imagine watching THAT take place below deck!

 

Most large cargo are designed lightly, and the cargo, especially in bulk carriers is part of the structural strength of the hull. That is they are stronger loaded than when they are unloaded.

 

Here's a concept that can be misleading, or perhaps I misunderstood. A structure, when fully charged, acquires a deformation which, until discharged, it is difficult to remove. But that does not mean that the structure is stronger: the structure is the same, just as strong as before, but distort it a bit more, it's hard.
Regarding the video, without having quantified the problem (deformation), it appears that the structure is too deformed. If I were the owner, I'd be worried about my boat.

 

I used a poor choice of words to state what is a complicated subject. But the point is, the load is considered in the design as adding to the structural integrity of the ship.

 

Like Saturn V fuel tanks..

 

All ships are limber for two good reasons. Economics and design requirements.

It is designed with a minimum amount of material while keeping within the safety standards. It is designed to flex to absorb the shock of the waves.

This flexing design principle is not limited to ships. Bridges flex, so does airplane wings. The bridge flex to sway with the wind. It is built with the minimum of structure so as not to present a large cross sectional area to the wind. The airplane, when taking off, its wings flex downward reducing drag and adding to ground effect. In flight, the wings flex upward, adding stability.

 

Build anything 400ft long & it's going to flex. Cool video ha' !