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Jun 11 07 11:52 AM
Jun 11 07 11:54 PM
Quote:...but the Vanguard was better armoured (particulary against underwater hits- where the Iowa was particularly poor)...
Jun 12 07 1:18 AM
Jun 20 07 6:43 PM
U really did not think a brit was gonna admit that the U S N had a better ship did you ?
Jun 21 07 1:13 AM
Jun 21 07 5:03 AM
Jun 23 07 3:38 PM
ideal cardonald factured 15"/42 (values: 1800 lbs weight with 1600 lbs
body weight, all nose coverings intact at impact) fired against 12"
armour at 20 deg. impact obliquity with 1500 fps striking velocity.
Type of Armour                remaining velocity stopping powerin %
Compound (19th century)        824 fps--8--        45%
Krupp old (1884-1925)                766 fps--7-- 49,1%
average KC (pre 1911)        758 fps--7--        49,5%
Harvey Nickel (1900-10)        756 fps--7-- 49,6%
jap. VH (1937-45)                752 fps--7-- 49,9%
average KC (1911-1921)        738 fps--7--        50,8%
british KC(1911-25)                738 fps--7-- 50,8%
US "A" (1935-43)                729 fps--6--        51,4%
Krupp mid (1925-35)                716 fps --6-- 52,3%
US "A" (1944-50)                701 fps--6--        53,3%
US other A(1911-25)                688 fps --5-- 54,1%
british KC(1922-30)                673 fps--5--        55,1%
average KC (1922-1930)        673 fps--5-- 55,1%
betlehem A(1911-25)                638 fps--4--        57,5%
Krupp new (1935-45)                633 fps--4--        57,8%
Wilkowitz (1910-35)                602 fps--3-- 59,9%
british KC(post 1930)                582 fps--2-- 61,2%
average KC (post 1930)                507 fps--1-- 66,2%
Terni CA (1935-45)                478 fps--1--        68,1%
Jun 24 07 2:39 AM
Aug 30 07 7:04 AM
Well Nathan45 posted this earlier this year.
Re: Iowa versus Vanguard - biased?
Warships1 and NavWeaps Discussion Boards
... Battleship Vs Battleship
...... Re: Iowa versus Vanguard - biased?
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Subject: Re: Iowa versus Vanguard - biased?
Posted By: Nathan45 Registered Member
Posted At: 6/23/07 11:59
I calculated the following based on facehard, originally posted on the
tanks of WWII board under my alias Eric45.
Short answer, at a realistic 20 degree target angle, Vanguard will have to
close to within 16000 yards to get even a partial penetration for most
hits, effective penetration at all but point blank range is unlikely.
Lucky hits that avoid the splinter belt might penetrate but not further
then 18000 yards.
South Dakota can penetrate the machinery of Vanguard out to 26000 yards
effectively at 20 degrees, Iowa could probably do it at 28000. The
"sloped" magazine armor of vanguard could be penetrated effectively to
18000 yards, and partial penetration to 22000 yards, Iowa would probably
add 2000 yards to that.
The greater armored volume of Vanguard makes her belt better against
lighter guns, but against the 16/50 its virtually useless, simply adding
more splinters, and assuring the shell detonates within the ship.
There is no comparison for turret protection.
Note that most hits on the belt at target angles of ~13 degrees or more
will likely hit the splinter belt at over 15 degrees and be decapped,
however, I calculated the penetration with both uncapped and capped
Notes on decapping. Basically at 15 degrees combined obliquity, the Iowa
splinter belt will decap Vanguards shells, although there are a few
trajectories where it wont hit the splinter belt.
South Dakota (Or Iowa.). 12.2in (12.1) US class A armor belt, backed by
2in of cement and .875STS. Splinter plate of 1.25in STS
Vanguard. Machinery is 12.76in British CA armor, with 2in cement and .75
Class D backing. Vertical. Magazines are 13.75in of CA armor, same
backing. Contoured to the hull so its sloped, I assumed 10 degrees which
looks to be about the maximum its sloped.
At 10 degrees, Vanguard can penetrate South Dakota's belt to 20000 yards,
although at this range it can only hole the belt. Effective penetration
occurs at 18000 yards. This assumes the 15in avoids the 1.25in splinter
belt. If it hits the splinter belt and is decapped, it fails completely at
16000 yards. At 14000 yards is just at the obliquity limit of being
decapped (Obliquity on the 1.25in splinter belt is 14.18 degrees, with 15
needed for decapping), if the roll of the ship makes the shell decap, at
14000 yards vanguard can only partially penetrate south Dakotas belt.
At 20 degrees, the shell will always be decapped if it hits the splinter
belt, (Probably about 90% of hits). Decapped 15in shells can only
penetrate South Dakota's belt to 14000 yards (Partial penetration). They
fail completely at 16000 yards. At 12000 yards they penetrate but in
ineffective condition. If the shells manage to not be decapped, they can
penetrate to 16000 yards (effective), failing completely at 18000 yards.
At 10 degrees South Dakota can penetrate the vertical 12.76 machinery belt
of Vanguard to 26000 yards, and fails completely at 28000 yards. The
sloped magazine belt of 13.74in can be penetrated effectively to 20000
yards, partial penetration at 24000 yards, and fails completely at 26000
At 20 degrees South Dakota can penetrate the machinery to 26000 yards,
failing completely at 28000. It can penetrated the sloped magazines to
18000 yards effectively, partial penetration to 22000 yards, and fails
completely at 24000 yards.
The turrets and barbettes of South Dakota are also much better protected,
glancing hits can be withstood at very close ranges, while Vanguards
turrets can be taken out at almost any range.
As far as decks go, vanguards magazines are slightly better, her machinery
is slightly worse the South Dakotas. The real difference is the deck
smashing 2700lb shell. M79APCBC doesn't calculate US shells correctly, but
Massachusetts put a shell into Jean Bart's magazines at about 25000 yards,
and this was through comparable protection to vanguards magazines. So
South Dakota could probably penetrate Vanguards magazines at around
25000-26000 yards, her machinery around 23000-24000, subtract (Or add) up
to 5000 yards for the effect of bad rolling. Vanguard would probably need
about 34000 yards to get through South Dakota's decks, same reduction
possible due to rolling.
Feel free to check my calculations.
Aug 31 07 4:53 PM
Aug 31 07 8:53 PM
Red Admiral wrote:
You don't need to keep the shell out to render it ineffective. The shell will detonate a certain time after the fuse is set (when encountering the belt
armour). It is then slowed down a lot by the belt armour and is either rejected, passes through, or a bit of both. All of the analysis above takes no account
of the splinter armour mounted around Vanguard's magazines (and the KGVs in late war). Because of this, it makes it almost impossible for a shell to
effectively get to the magazines or machinery spaces (I can't remember if the splinter armour goes around the machinery spaces) and explode.
There is very little difference in the effectiveness of either vessel in practice.
Aug 31 07 10:18 PM
ickysdad wrote:Ok but what about US splinter armor? I'm sure there's some in there somewhere.
There is only the splinter deck below the armour deck (0.625") but it would be impossible for a penetrating belt hit to go through this plate (going
Aug 31 07 11:16 PM
Sep 9 07 9:34 PM
What I'm saying is that to get to the machinery/magazine spaces through the lower belt you would also hit some of the torpedo bulkheads and holding
bulkhead. Then there's also the 3rd. deck which I assume has some STS in it.
Your observation is correct. If a projectile has a trajectory ending in the machinery spaces/magazines via upper belt, it will not only pass the decapping
plate but also the extension of No. 2 bulkhead #35 STS. This will slow down the projectile altough in how far this will be sufficiant to prevent a lower belt
penetration is depending on the specific conditions of impact and cannot be answered in general (from case to case only). The problem with the 3rd deck are
1-)The shell does not necessarely need to pass the 3rd deck to reach the vitals at all. Altough beeing a very small area to hit (and thus should be
considered unlikely), the projectile may hit the upper part of the lower belt UNDER it´s joint to the 3rd deck - all without making any underwater trajectory
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