16" Naval Gun; Two 16-Shot Groups. Accurate?
- Thread starter Bart B.
- Start date
- Status
1stmarine
Member
No.
Corn-Picker
Member
About 100 MOA according to my (mental) calculations.
Edit: What does 50 cal mean? I assumed 16" meant a 16" diameter projectile from a ship based gun.
GBExpat
Member
"Back in the Day", the length of the cannon barrel was often expressed in terms of how many "calibers" long it was (bore length divided by diameter of the projectile) ... and this was referred to as the barrel's calibre.
Duster340
Member
- Joined
- Jan 11, 2015
- Messages
- 850
Actually, I think the aircraft carrier knocked the battleship off as top dog on the highseas
Some details:
Down angle of fall at range;
25,000 yards, 21 degrees.
36,000 yards, 38 degrees.
Group size at right angles to fall angle will be smaller.
Muzzle velocity spread was 20 to 60 fps depending on powder type. .
Down angle of fall at range;
25,000 yards, 21 degrees.
36,000 yards, 38 degrees.
Group size at right angles to fall angle will be smaller.
Muzzle velocity spread was 20 to 60 fps depending on powder type. .
Last edited:
That would be true if the picture shown was the actual target (a huge vertical target with a life-size image of the Pentagon on it.) However, the Pentagon is a relatively flat target at 25K yards. So the rounds will be coming in a little flatter than the image indicates. If the ship was firing from due south, then the 25K yard grouping is about 275 yards wide. 275/25000 = .011 which is the sin of 38 MOA. It's difficult to say what the height range of the grouping would be, but I'd wager it's less than the horizontal spread.
Since the target (the central court of the Pentagon) is destroyed, it's hard to call it inaccurate.
Sistema1927
Member
Looks like pretty good accuracy, seeing as the "gun platform" isn't stationary.
The old ships were retired not due to their lacking of firepower or accuracy but due to the high cost of maintaining them when a smaller and cheaper ship could employ accurate and effective missiles at longer ranges.
Is that group accurate? Considering the effect on target of those rounds, it is accurate enough ill say that. I will leave the math to others, but those guns are legendary for the ability to put massive ordinance on target. In okinawa they were used to close cave mouths because of the size and accuracy of the shells.
Is that group accurate? Considering the effect on target of those rounds, it is accurate enough ill say that. I will leave the math to others, but those guns are legendary for the ability to put massive ordinance on target. In okinawa they were used to close cave mouths because of the size and accuracy of the shells.
-
Yes, lots less due to projectile fall angles less than 40 degrees
One can calculate group sizes in trajectory axis and vertical planes with trig functions for their angles of fall with the horizontal plot shown. 21 and 38 degrees. The reference point on earth should be the closest shot hole for each range.
In naval gunfire on surface craft, a "danger zone" is used. That's the target range band the craft can have that makes hits possible between its waterline and topmost structure. It's calculated with projectile angle of fall and craft height. Shorter as range increases.
Last edited:
Steel Horse Rider
Member
If you have read any of the history of the naval battles in the Pacific in WWII you would know that there was little comparison from ship to ship despite which side they were on. Accuracy from a ship as a firing platform, due to the fact that they were always in motion as well as the target, was dependent on who was the most practiced and who had the best spotting as constant aiming corrections were necessary to keep the shells on target. Accuracy with a naval cannon explosive shell is better compared with a shotgun burst than with a center fire rifle cartridge due to the size of the affected impact area. The Battle off Savo Island is an excellent read concerning naval gunnery and how large bore naval rifles are not necessarily the best in a fight.
Officers'Wife
Member
Hmm, shells weighing in excess of a ton of explosive... It would seem prudent to factor in the kill radius along with the MOA. Even with 400k square yards of area in the graft, I would not care to be the one on the receiving end of the bombardment.
jrmiddleton425
Member
- Joined
- Jan 18, 2011
- Messages
- 663
If I read it right, each circle is a 16 round group. There are 11 circles cutting a 600 by 600 foot target box. That's 176 rounds in about eight and a quarter acres. With the blast radius of a 2000-ish pound HE shell, all that's left is a smoking hole. How accurate does it NEED to be?
looks like most shot are hitting a 114 or so MOA, with more on the CEP zone, so im going to say very accurate for 14 miles, but not gonna hit paper at 100 yards. Its your call, but I think it hits what it needs to. These guns were supposed to hit objects the size of battle ships, and cities, so I think they meed the requirements
I don't believe you did read it right. Each circle is the impact site of a single round. There are 16 rounds shown for the 25K range and 14 for the 36K range. Two rounds from the latter group missed the "paper".
Couple of considerations here. The blast radius of a 16" shell is about 150 yards. Thats a 900' circle. Each leg of the Pentagon is a bit over 900'. Even if the shrapnel doesn't hit you the concussion will kill you.
Pretty good effect on target I'd say. Cut those ranges in half and the Pentagon would pretty much be destroyed.
Pretty good effect on target I'd say. Cut those ranges in half and the Pentagon would pretty much be destroyed.
...in three dimensions as well depending upon the seas at the time.
Turret captain of New Jersey's no. 2 turret told me blast zone in Vietnam jungles defoliate trees over 50 yards from high capacity rounds detonation point. Had lunch with him on board in 1968. He mentioned those hi caps were sometimes used to clear a landing site for helicopter missions.
But the gun barrels are virtually still in space.
A gyroscope gave ship roll and pitch angles via gear train to the mechanical computer calculating deck plane gun train and elevation angles electrically sent to turrets compensating for ship motion. Gun angles were kept within a few MOA in space about ballistic caculations for target range, course and speed.
Last edited:
I'd suspect hitting another battleship at extreme ranges is all that was necessary since only another battleship could hit back.
We took a tour of the USS Alabama around 1980 and the mechanical fire control computer was a thing of beauty and a joy forever. At the time, the tour guide said that electronic computers could not match the accuracy of the old mechanical unit. Of course, computing power of electronic devices today have improved vastly since 1980 so I'm sure a smart phone would provide more accurate calculations today.
It would be interesting to know where in the life of the barrel the tests were made and the ammunition used. The armor piercing anti-ship shells wore barrels out lots faster than high explosive or practice shells.
- Status
Similar threads
- Locked