military@att.att.com (Bill Thacker) (04/21/89)
From: military@att.att.com (Bill Thacker) From tonight's CNN Headline news: The 47 killed crewman (all of whom were within the turret) have been flown to Dover AFB, having been unloaded from the Iowa in Roosevelt Roads, Puerto Rico. Services will be held in Norfolk Naval Base. 12 firefighters were slightly injured. 11 crewman deeper in the turret structure (CNN referred to the powder magazine, but from the area their graphic indicated, I believe they meant the powder handling room) were uninjured. Iowa herself is now en route to Norfolk. All damage is confined to the #2 turret, and the ship's seakeeping ability is unimpaired. The Navy seems confident that they will be able to repair the turret without replacing it (which would be, I'd think, a prohibitively costly process). This is considered the worst naval accident in 12 years. (What was that accident ?) The Navy first considered the possibility of ignition by residual embers; this was the first firing of #2 turret (according to CNN, #1 turret had fired 4 rounds previously). They apparently now are considering the possibility of "volatiles from the powder." ---- A little information on Iowa's turrets: Weight: 1700 tons Diameter of barbette interior: 37'3" Firing cycle: 30 seconds Armor: Face: 19.7" Sides 9.5" Rear 12" Roof 7.25" (From Campbell, _Naval Weapons of World War Two_, 1985, Naval Inst. Press.) I'm unable to find the figure for turret crew: 47 sounds about right for the actual gunhouse section of the turret (i.e, discounting the lower structure). For what it's worth... - - - - - - - - - - - - - - - - - - - - - - - Bill Thacker moderator, sci.military military@att.att.com (614) 860-5294 "War is a matter of vital importance to the State; the province of life or death; the road to survival or ruin. It is mandatory that it be thoroughly studied." - Sun Tzu
jallred@bbn.com (John Allred) (04/22/89)
From: jallred@bbn.com (John Allred) In article <5795@cbnews.ATT.COM> military@att.att.com (Bill Thacker) writes: > > > <more on the USS Iowa explosion> > >This is considered the worst naval accident in 12 years. (What was >that accident ?) Perhaps it's the Marine EA-6A crash on the Nimitz, which killed on the order of twenty men. If I recall, the probably cause of this accident was the pilot self-administering anti-histamines prior to launch. Traces of THC were also found in several of the dead crewmembers. This event kicked off the "zero tolerance" drug policy. ____ John Allred BBN Systems and Technologies Corp. (jallred@bbn.com) "Send lawyers, guns, and money ..."
military@cbnews.ATT.COM (William B. Thacker) (04/22/89)
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"
henry@zoo.toronto.edu (Henry Spencer) (04/22/89)
From: henry@zoo.toronto.edu (Henry Spencer) >The Navy seems confident that they will be able to repair the turret >without replacing it (which would be, I'd think, a prohibitively >costly process). If I recall correctly, one reason for abandoning the original plan to remove the #3 (aft) turrets and install armored hangars for Harriers was the difficulty of finding a crane that could lift one of those turrets! Each of the things weighs as much as a destroyer. Henry Spencer at U of Toronto Zoology uunet!attcan!utzoo!henry henry@zoo.toronto.edu
henry@zoo.toronto.edu (Henry Spencer) (04/24/89)
From: henry@zoo.toronto.edu (Henry Spencer) >Why aren't modern ships armored? Shouldn't a nuclear aircraft >carrier, for instance, have enough power to push extra armor around? Only if you deduct something else. There is never enough space or weight available in a warship. Useful amounts of armor are very heavy. Even the Iowas aren't armored everywhere: command centers are inside masses of steel, turrets and magazines have heavy armor, and there is a substantial armor belt at the waterline to prevent holes that could let in water... but much of the rest of the ship gets to take its chances against anything heavy. Carriers are a particular trouble spot because aircraft operations put a premium on speed -- every knot of forward speed is one more knot of airspeed to help an aircraft that's landing or taking off. Armor fell out of fashion after WWII, since it wasn't useful against nuclear weapons. Ship designers were happy to have the extra weight for other things, and haven't been enthusiastic about reintroducing armor. >>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... Note that we may have a terminology problem here: the "face" of the turret may be not the relatively small and low "nose" of the turret, but the large and very steeply slanted (almost horizontal) "forehead". The "roof" may be just the rearmost portion which really is horizontal. I could be wrong, my references aren't handy. Henry Spencer at U of Toronto Zoology uunet!attcan!utzoo!henry henry@zoo.toronto.edu [mod.note: I'm sure the term "face" means the actual front of the turret, perforated for the guns. On the Iowa's main turrets, unlike those of many (now-defunct) battleships, the entire roof is flat. - Bill ]
malloy@nprdc.navy.mil (Sean Malloy) (04/24/89)
From: malloy@nprdc.navy.mil (Sean Malloy) In article <5839@cbnews.ATT.COM> military@cbnews.ATT.COM (William B. Thacker) writes: >[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 ] The barrel length has a much larger effect on the accuracy of the gun than it does on the range; the barrel length allows a faster rotation of the shell, which increases its stability in flight, which reduces the amount it deviates. The contribution muzzle velocity makes on accuracy is primarily due to the ability of using a flatter trajectory for the same range, reducing the flight time that the shell is exposed to wind and other causes of deviation. Compare the CEP of an antitank gun with a howitzer at the same range and muzzle velocity -- the longer barrel makes the AT gun more accurate. Sean Malloy | "The proton absorbs a photon Navy Personnel Research & Development Center | and emits two morons, a San Diego, CA 92152-6800 | lepton, a boson, and a malloy@nprdc.navy.mil | boson's mate. Why did I ever | take high-energy physics?"
maniac%garnet.Berkeley.EDU@ucbvax.Berkeley.EDU (George W. Herbert) (04/29/89)
From: maniac%garnet.Berkeley.EDU@ucbvax.Berkeley.EDU (George W. Herbert) In article <5851@cbnews.ATT.COM> henry@zoo.toronto.edu (Henry Spencer) writes: >Armor fell out of fashion after WWII, since it wasn't useful against >nuclear weapons. Ship designers were happy to have the extra weight >for other things, and haven't been enthusiastic about reintroducing armor. That's not the only reason armour fell out of fashon. There were two more that mattered, perhaps much more: 1. Armour proved more or less ineffective against aircraft bombs and 2. Ship design is always a tradeoff. If you dedicate weight to armour, there is less for fuel, weapons, etc. They needed more weapons and fuel. george william herbert maniac@garnet.berkeley.edu
jrll@Portia.stanford.edu (john ralls) (05/05/89)
From: john ralls <jrll@Portia.stanford.edu> The accident 12 years ago would be the collision between Belknap and Kennedy. The superstructure of Belknap was torn off by Kennedy's starboard sponson, and in the process, some jet fuel tanks on the sponson were opened, dumping the fuel onto Belknap. The fuel was ignited by the boiler exhaust, resulting in a truly impressive fire. One of my instructors at Supply Corps School was Gunnery Officer on Belknap at the time. He attributed the small loss of life (only 11 killed) to the fact that the Captain did not call for general quarters when colision was imminent; that would have put a large part of the crew topside in the fire control spaces. Belknap was towed back to the US and refitted; I recall that it took more than three years to put her right. Incidentally, it was that casualty which got the Navy thinking that aluminum superstructures are not such a smart idea. I believe that the Arleigh Burke (DDG 51) will be the first US destroyer to have a steel superstructure since the 1950's. John