terryr@ogicse.ogi.edu (Terry Rooker) (06/05/90)
From: terryr@ogicse.ogi.edu (Terry Rooker) In article <16041@cbnews.ATT.COM> ames!ames!claris!portal!cup.portal.com!mmm@uunet.UU.NET writes: > > However, I have set the fact out plainly here. The "match-box" test >[accompanying picture shows hand holding matchbox between thumb and forefinger >in its smallest dimension] gives opportunity to visualise clearly the thinness >of the skin on the intactness of which the battleship depends for her ability >to remain afloat. > Is it so much amiss to liken the hull to a huge bubble?" > >or the New Jersey, is like? Do recent warships have thin hulls like those >described in this book? > Modern ships still have hull plates that are this thick. If you think about it it isn't that surprising. The hull is built on a frame that is built from the keel. It is this frame that actually resists the pressure of the water and maintains the shape of the hull. The skin of the ship only needs to be thick enough to span the distance between stringers. On most ships the frames are on the order of 2 feet apart. The metal skin is only unsupported for that distance. If you wanted a monocoque(sp?) type of hull, then it would have to be much thicker, which is part of the reason that style is not used on ships. A double bottom is not only expensive, but it takes up a lot of volume. In a warship the latter is almost as important as the cost. Even if there is not a double bottom, tanks and voids on warships tend to be outboard near the water line to provide some of the advantages of a double bottom without the expense. For what it is worth, Soviet submarines tend to have double hulls, although in this case, the space is used for ballast tanks. It is one of the supposed advantages of Soviet sub design. There is great fear in the West that the separation from the actual pressure hull (upto 6 feet!) may render Western ASW weapons ineffective. Older ships may not even have 5/8ths of an inch in hull plate. There are numerous sea stories about screwdrivers slipping and punching holes in hulls. I believe there are cases where the hull was measured at near, or less than 1/4 of an inch! Kinda makes the thought of 30 foot swells in a quartering sea kinda scary :-) -- Terry Rooker terryr@cse.ogi.edu
whh@PacBell.COM (Wilson Heydt) (06/06/90)
From: whh@PacBell.COM (Wilson Heydt) In article <16041@cbnews.ATT.COM> ames!ames!claris!portal!cup.portal.com!mmm@uunet.UU.NET writes: > " . . . I have many >times found it a source of wonderment, sometimes even of outspoken disbelief, >that the thickness of the under-water skin of a modern battleship should be >no more than five-eighths of an inch." > >[mod.note: Without taking the time to look up exact thicknesses, I can >say this is essentially correct. > > The ideal underwater attack would be to explode a mine or torpedo >directly below a ship's keel, so that the flat bottom would leave the >explosion force nowhere to go but up into the hull; as of WWII, however, >fusing technology was not reliable enough to do this (witness the failure >of the magnetic pistols used on early American torpedoes, for example). >I wonder how much that has changed today. - Bill ] I have had accounts from a well connected friend that the torpedos that sank the General Belgrano (the Argentine cruiser that was sunk during the war between Briatain and Argentina over the Falklands), dropped one of the barbettes through the keel. Perhaps someone has written references to either confirm or deny this claim? (Another friend knows someone who claims to have been standing on the hanger deck of a British carrier watching the Atlantic Conveyor get hit by an Exocet. The official British line is that the carriers were nowhere near that action . . . Hmmm . . .) --Hal ======================================================================= Hal Heydt | An earthquake is Mother Nature's Analyst, Pacific*Bell | "silent" pager going off . . . 415-823-5447 | whh@pbhya.PacBell.COM |