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DS4DUMMIES -> RE: Lies repeated and repeated and repeated... (5/28/2008 9:00:33 AM)
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quote:
ORIGINAL: LadyEllen
Interesting, that as a ship sinks the rats scramble out seeking refuge from the waters about to engulf them too
Of course, ships generally only sink if they are holed below the water line, rotten through to the keel or were poorly constructed in the first place.
If rats could talk, they would be invaluable for telling us quite why a ship sank, since generally they have an up close and personal relationship with suspect parts of the construction by way of their places of habitation on board.
E
Let's leave ships out of this :) BUT...seeing as the subject was brought up....here is the ACTUAL reality of why ships sink.
Ships do not necessarly sink from being holed below the waterline. The vessel I command can be holed in multiple places below the waterline and not sink. The engineering concept is something called "floodable length" and "damaged stability". Ships sink when their accumulated weight exceeds their available displacement at a given waterline and trim/heel. Ships can sink from holes ABOVE the waterline, if heeling and downflooding or a free-surface/stability issue is involved. (See the loss of some of the European RO-RO ferries built in the 1980's) Ships can sink from structural failures caused by excessive hogging or sagging moments induced by waves, or grounding. Ships can sink from being overloaded, or from having too high a center of gravity and too low a metacenter, or excessive free surface in their tanks and enclosed spaces. They can sink from a lack of form stability, improper loading, and from being hit by Exocet missles. Ships can sink from failure of a packing gland or shaft seal around a propeller shaft. Ships can sink from failed or defective welds, or on very old steel ships, rivet drift. Wood ships can sink from failed seam caulking.
Poorly constructed vessels seldom initially sink, if they are certified by a Classification Society. If they are that badly designed or built, they don't usually get far from the shipyard outfitting dock anyway. Most soon-after-construction related losses have to do with stability, not hull failure.
With regard to rats.....ships are my life. I have yet to see a rat infestation on a US flag ship. Ratproofing is a part of any design spiral and is required under US law and international law. Curiously, a ship that WAS famous for a rat problem was the RAINBOW WARRIOR, operated by Greenpeace. The French fixed that problem by blowing it up in New Zealand. If you read the casualty report, there is no mention of the rats deserting the ship, (I AM NOT REFERING TO THE CREW) so it may not be universally true that rats desert a sinking ship. However, if they are bouyant, they may escape anyway, via Archimedes Principle.
For the record...steel does not rot. It corrodes, or it fails by fracture or cyclic stress or over-stress. It may surprise you to know that virtually all steel ships experience stress fractures in their lifetime, no matter how well designed.
It should be noted that rats do not normally inhabit places on ships critical to structural integrity so they likely would have little to say at a Coast Guard casualty investigation hearing. . When they are found, it is usually behind joiner work in stores spaces, under and behind things like refrigerators and stores lockers or pantries, inside seldom-used enclosed spaces that have the access they require, or near to inhabited spaces on the ship, from whence they can easily venture out and obtain nourishment. The most important structual areas on a ship are normally to be found elsewhere.
Wood however, does rot.
Just wanted to elevate the discussion a bit :)
DS4
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