If Titanic got damaged by the iceberg in Boiler Room 2?


Mar 22, 2003
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What's that?
Basically, free surface effect is the change in stability of a vessel caused by liquids moving about freely in a hold or a compartment. It effectively raises the center of gravity of the vessel causing a loss in stability which can lead to the vessel capsizing. There are a few on-line articles about it, and they are quite technical if you really want to get into it.
 
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Cam Houseman

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Basically, free surface effect is the change in stability of a vessel caused by liquids moving about freely in a hold or a compartment. It effectively raises the center of gravity of the vessel causing a loss in stability which can lead to the vessel capsizing. There are a few on-line articles about it, and they are quite technical if you really want to get into it.
Thanks. Was this the case for the Andrea Doria? Or was the collision that bad, and the flood thanks couldn't correct it?
 
Mar 22, 2003
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Thanks. Was this the case for the Andrea Doria? Or was the collision that bad, and the flood thanks couldn't correct it?
Cam, it seems that the Doria was penetrated in the way of an empty fuel tank. She took on a sever list very early. My good friend Capt. Charles Weeks plotted her list Vs. time. This is what he came up with:
1597532882002.png
 
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Stephen Carey

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Most ship's with severe amidship's damage tend to capsize because of a loss of translational stability. I'll have to check, but I think it has something to do with what is called free surface effect.
It's in your article Sam, where you show the damage as perceived by Wilding in the enquiries after the event (2 and 3 compartment damage drawings showing bodily sinkage without capsize). The Olympic class - by virtue of transverse bulkheads only - would not capsize in calm water as the likes of Lusitania did (longitudinal compartments), and this was covered in the article that you referenced (I went to the actual RINA talk by H&W in Glasgow sometime in the 90s - "Titanic investigated by modern computer methods"). Both Wilding and Peskett agreed - as discussed in the above - that with similar damage M&L would likely capsize, as evidenced by Lusitania a few years later.
Free surface effect does indeed raise the CoG towards the added mass, though it's a virtual shift. With water in the bottom of the ship, the CoG again moves - actually - towards the added mass, which in the case of flooding, is low down in the bottom. Titanic sank even keel, as did Costa Concordia before she touched on a rock near the shore, which shifted the otherwise stable water in some 5 or 6 compartments to starboard, which eventually capsized her. However rough weather can cause rolling which could make things worse where free water even low down can eventually overcome the righting lever and capsize the ship.
Empress of Canada and Normandie are classic examples of the LAFB sinking ships in calm water by means of free surface with the water all in the upper decks, resulting in capsize in a single roll as stability disappeared. RN ships have drop-down pipes to drop any firewater down from the upper decks to avoid capsize (they have WT decks). These had WT screw covers which you groped for in the Damage Control Simulator when under 3 feet of water.
On bulkers we would sometimes in calm weather part fill a hold with water to do a dinghy inspection of the hold plating. However if even a small roll was induced, it was noticeable how the effect on perceived stability was magnified by the free water in the hold. The effect in tankers however was minimal, as they are subdivided longitudinally into 3 tanks athwartships, as it's breadth that effects free surface, not length or the amount of water.
 
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Cam Houseman

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It's in your article Sam, where you show the damage as perceived by Wilding in the enquiries after the event (2 and 3 compartment damage drawings showing bodily sinkage without capsize). The Olympic class - by virtue of transverse bulkheads only - would not capsize in calm water as the likes of Lusitania did (longitudinal compartments), and this was covered in the article that you referenced (I went to the actual RINA talk by H&W in Glasgow sometime in the 90s - "Titanic investigated by modern computer methods"). Both Wilding and Peskett agreed - as discussed in the above - that with similar damage M&L would likely capsize, as evidenced by Lusitania a few years later.
Free surface effect does indeed raise the CoG towards the added mass, though it's a virtual shift. With water in the bottom of the ship, the CoG again moves - actually - towards the added mass, which in the case of flooding, is low down in the bottom. Titanic sank even keel, as did Costa Concordia before she touched on a rock near the shore, which shifted the otherwise stable water in some 5 or 6 compartments to starboard, which eventually capsized her. However rough weather can cause rolling which could make things worse where free water even low down can eventually overcome the righting lever and capsize the ship.
Empress of Canada and Normandie are classic examples of the LAFB sinking ships in calm water by means of free surface with the water all in the upper decks, resulting in capsize in a single roll as stability disappeared. RN ships have drop-down pipes to drop any firewater down from the upper decks to avoid capsize (they have WT decks). These had WT screw covers which you groped for in the Damage Control Simulator when under 3 feet of water.
On bulkers we would sometimes in calm weather part fill a hold with water to do a dinghy inspection of the hold plating. However if even a small roll was induced, it was noticeable how the effect on perceived stability was magnified by the free water in the hold. The effect in tankers however was minimal, as they are subdivided longitudinally into 3 tanks athwartships, as it's breadth that effects free surface, not length or the amount of water.
I like Sam's website, there's so much to learn!
 

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