Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!dogie.macc.wisc.edu!indri!unmvax!tut.cis.ohio-state.edu!osu-cis!att!cbnews!military From: military@cbnews.ATT.COM (William B. Thacker) Newsgroups: sci.military Subject: Re: Update on USS Iowa Message-ID: <5839@cbnews.ATT.COM> Date: 22 Apr 89 04:31:22 GMT References: <5795@cbnews.ATT.COM> Organization: Center for Supercomputing R&D (Cedar), U. of Ill. Lines: 60 Approved: military@att.att.com From: uiucuxc!uicsrd.csrd.uiuc.edu!mcdaniel (Tim McDaniel) In article <5795@cbnews.ATT.COM> and in another article military@att.att.com (Bill Thacker) writes all sort of good stuff. Thanks! Sundry questions: Why aren't modern ships armored? Shouldn't a nuclear aircraft carrier, for instance, have enough power to push extra armor around? The Iowa guns are 16"/50's, says Bill. What does the "/50" mean? Or is it "/50'", meaning "50 feet long"? [mod.note: The "/50" means that the length of the gun barrel is 50 calibers, i.e., 50x16" or 800 inches, long. The longer the tube, the greater the velocity, and, therefore, range of the shell. (The North Carolina and South Dakota classes which proceded the Iowas carried 16"/45's, which were less effective) - Bill ] How far above and below the waterline does the belt armor usually extend? [mod.note: Best estimate I can find is from about 12 feet above waterline to about 5 feet below; that's a guess from a section drawing. - Bill ] >Diameter of barbette interior: 37'3" "Barbette: the armored structure around a gun platform on a warship." [mod.note: In more modern usage, it is the armored tube upon which the turret sits. This protects the unarmored turret structure which reaches down into the magazines. - Bill ] >Armor: Face: 19.7" Sides 9.5" Rear 12" Roof 7.25" How counterintuitive! I would have thought roof > sides > rear > face, in order of vulnerability. (For example, the roof is the most vulnerable to long-range fire and aircraft.) Why the exact opposite, I wonder? [y.a.mod.note: Depends on the combat range. At closer ranges, trajectories are flatter, so the turret face (which, hopefully, is facing the enemy) is most likely to be hit. At longer ranges, the shells typically are falling at 45-60 degrees from horizontal; this glancing strike makes the roof armor much more effective. Finally, the roof takes up a large area, meaning that adding an inch there adds much more weight than that same inch added to the smaller frontal armor plate. - Bill ] -- Tim, the Bizarre and Oddly-Dressed Enchanter Center for ||| Internet, BITNET: mcdaniel@uicsrd.csrd.uiuc.edu Supercomputing ||| UUCP: {uunet,convex,pur-ee}!uiucuxc!uicsrd!mcdaniel Research and ||| ARPANET: mcdaniel%uicsrd@uxc.cso.uiuc.edu Development, ||| CSNET: mcdaniel%uicsrd@uiuc.csnet U of Illinois ||| DECnet: GARCON::"mcdaniel@uicsrd.csrd.uiuc.edu"