Grape Shot?

Originally posted by allenidaho
Keep in mind that an incoming missile can be intercepted. An anti-ship missile zooms your way, usually a ship will deploy another missile or a CIWS cannon (or both) to shoot it down.

How do you intercept a 16-inch artillery shell fired from a old naval gun like those on the USS Missouri? You want to defeat the modern navy, go old school.

Intercepting a 16" shell isn't as hard as you might think. They're 72" long, and travel at ~2,700 ft/sec when leaving the muzzle. They don't maneuver in flight, so the targeting solution is fairly simple. Give any decent math major 3 points on a curve, and he or she can give you a parabolic path connecting them. A digital fire control system can do the same, in milliseconds.

Standard USN gunnery doctrine was to engage between 20 and 30,000 yards. (All data following are based on the Mk 8 AP shell, fired at a battleship-sized target). At 20,000 yards, the hit percentage is around 10%, and the flight time is just under 30 seconds. At 30,000 yards, the hit percentage is around 3%, and the flight time is just over 50 seconds. That means that the point-defense system has 30-50 seconds to determine whether the shot is going to hit (or be a close enough miss to be dangerous), and if it is, to engage the incoming round. A 20mm Phalanx round has more than enough kinetic energy to alter the trajectory of a 16" AP round, and a Standard SAM can probably destroy the thing outright. They aren't that fast (compared to some things point defense has to deal with), they don't maneuver, and they aren't that numerous.

The above discussion becomes moot once you realize that while the Iowas have very heavy belt armor, and surprisingly resilient deck protection, their ability to actually fight hinged on systems that can't be armored. The radar antennas and optical rangefinders were always vulnerable to blast and shock...or to incoming fire.

Long story short, there are two ways to intercept a 16" round. One is to treat it like a medium-fast but very dumb missile and shoot it down, the other is to 'preemptively intercept' it by disabling the fire control system.

Don't get me wrong...I love the battleships...I've got more books, models, and photos of them than is probably healthy...but they're every bit as obsolete in modern warfare as HIJMS Mikasa, HMS Victory, or the USS Constitution.

reply to post by da pickles


Not if its encased and deploys after it leaves the barrel, and also they could set up a range system do it would disperse the steel balls at a certain range, they have that capability on smaller guns already so i would think it wouldnt be to hard to intograte it into the existing platforms.

Yeah grapeshot has proven itself to be effective because it was commonly used on the old sail-powered warships to mow down crewmembers on the enemy ship and it would work on modern warships if it used a proximity fuse to detonate close to the enemy warship.