Battleship big guns and target speed

[Plecostomus]

For all you naval buffs out there, here is a hypothetical match-up.

On it's way to a fleet exercise in 1926 the USS Florida (BB-30) is sucked through a time-warp and ends up in the Caribbean Sea around 1981. The USS Gemini a small missile armed hydrofoil moves in and engages the displaced battleship.

For whatever reason the Gemini can't engage the Florida with it's missiles, so she accelerates to full speed of 48 knots and moves directly twords the Florida, engages the Florida with it's 3" gun, loops around the ship and attempts to flee.

At any point in this scenario would the Florida be able to engage and score a hit on the Gemini with it's main battery or is this far outside the capabilities of the ship and battery?

 

[Cicero]

Since Florida carried 10 guns in its main battery which were each acapable of firing 2-3 times per minute, and had a top speed of 21 knots (giving a speed differential of 27 knots), I would suspect that Florida would be able to engage the Gemini with its main battery. If not, Florida's secondary battery, the operators of which were trained in tracking targets moving at roughly 27 knots, would almost certainly score hits on the smaller ship.

Unless Gemini's fire were incredible accurate, I doubt its main gun, even given its high rate of fire, would be able to do any real damage to the Florida.

 

[Plecostomus]

I know the secondary and AA batteries could strike the smaller ship I'm more interested if the big guns could score a hit on a target at that speed.

Working on a couple "improbable naval engagement" short stories inspired by a video game I play. I'm a stickler for technical accuracy though.

 

[Goliath]

From what I know of naval warfare, I don't think the Florida would even attempt to engage such a small fast-moving target with its main battery.

I think, instead, it would rely on its secondary battery, as it would against enemy destroyers. The Florida carried sixteen 5"/51 caliber guns.

The problem is rate of fire. A battleship's big guns took around 30 seconds to reload. Any hits it scored on a ship like the Gemini would be a matter of pure chance. I'm not even sure it could rotate its turrets quickly enough to keep up.

By contrast, each gun in the secondary battery could fire several shots a minute. But from what I've read, their fire control was comparatively poor, so they'd probably be blasting away wildly at something moving as fast as 48 knots.

My guess would be that the Gemini would be able to get away, unless the Florida scored a lucky hit.

 

[Cicero]

^ I presumed a moving Florida, which would significantly improve the battleship's odds.

 

[Goliath]

^Yes.

I guess I presumed a sitting-there-thinking-"WTF-just-happened?" Florida.

 

[Plecostomus]

^ I presumed a moving Florida, which would significantly improve the battleship's odds.

^Yes.

I guess I presumed a sitting-there-thinking-"WTF-just-happened?" Florida.

Good point.

I guess I have to decide if she's underway and at what speed. Given they have no idea what just happened I'm assuming she's underway at a relatively low speed until the lookouts spot the PHM approaching.


That brings up another question I have to research: lookout ranges and at what point the Florida would become aware they are being set upon.

 

[Caliburn24]

The question I would ask is how far can the main guns on the Florida depress? Or more simply, how close does the Gemini need to get before it is too close for the Florida to hit?

But it wouldn't really matter. The Gemini wouldn't be able to significantly damage the Florida using only her gun armament.

 

[HobartFloyt]

For all you naval buffs out there, here is a hypothetical match-up.

On it's way to a fleet exercise in 1926 the USS Florida (BB-30) is sucked through a time-warp and ends up in the Caribbean Sea around 1981. The USS Gemini a small missile armed hydrofoil moves in and engages the displaced battleship.

For whatever reason the Gemini can't engage the Florida with it's missiles, so she accelerates to full speed of 48 knots and moves directly twords the Florida, engages the Florida with it's 3" gun, loops around the ship and attempts to flee.

At any point in this scenario would the Florida be able to engage and score a hit on the Gemini with it's main battery or is this far outside the capabilities of the ship and battery?

IMO the Florida wouldn't even attempt to use main batteries, and I doubt the main guns could train quick enough to engage such a target in any kind of dynamic sense anyway. This is why the secondary battery exists, to engage targets that move faster than the main battery can track effectively.

The Mark V 12in/45 caliber naval rifles that the Florida carried had a theoretical range of 20,000 yards with 15 degrees elevation and the 870lb projectile at 2-3 rounds a minute. Leaving aside the question of even seeing the target at ranges over 10K yards, I suppose if everything went the Florida's way and she got a good fire control solution with the target far enough out, then yes she could choose to engage with the main battery to try and bushwhack the Gemini on its straight-in approach, but that would be highly unlikely. See, the Geminis method of approach would be interpreted as a torpedo attack and therefore not a threat until well inside the range of the secondary battery due to the limited range of torpedoes.

 

[Bloodwhiner]

It is also likely a hit by the main batteries of the Florida would pass through the Gemini without detonation. The hull armor was too thin to trigger the warhead as it was designed to penetrate the thick belting of a capitol ship.

And the Gemini's 3" shells would be like me hitting a professional heavyweight boxer. They would feel it but more as an annoyance than as a true threat.

 

[Plecostomus]

See, the Geminis method of approach would be interpreted as a torpedo attack and therefore not a threat until well inside the range of the secondary battery due to the limited range of torpedoes.

Bingo. From the Gemini's POV they are trying to get a good visual on the "intruder" and get their attention and possibly talk to them by flag/blinker.... From Florida's POV they see a small nimble ship coming in at high speed so they prepare to repel a torpedo attack.

It is also likely a hit by the main batteries of the Florida would pass through the Gemini without detonation. The hull armor was too thin to trigger the warhead as it was designed to penetrate the thick belting of a capitol ship.

The Gemini is a small ship. A direct hit even passing through would do severe internal damage and result in a kill. I went below decks on the Pegasus years ago and I can remember the lower decks being full of engines.

And the Gemini's 3" shells would be like me hitting a professional heavyweight boxer. They would feel it but more as an annoyance than as a true threat.

The Gemini has no idea what they are up against until they get into visual range by then they are under fire. Also the upper superstructure is unarmored, so the 3" gun could do some damage up top. Seen plenty of examples over the years looking back through the battlehship archives.


Now some of you are begging the question of "communication!"

I don't know if the Florida has radio/wireless at this point in history, and if it does I don't know if they could even hear the Gemini talking to them. That'd leave naval Flag communication, wich is near universal across the ages. This is one of the reasons the Gemini is on appoach when the Florida opens fire.

 

[Goliath]

^I can't say for certain, but I would be very surprised if the Florida had not been equipped with a wireless set by 1926.

 

[Plecostomus]

^I can't say for certain, but I would be very surprised if the Florida had not been equipped with a wireless set by 1926.

Could a wireless set from "back then" talk to a modern (1981-ish) communication system?

I'm going to assume no for the simple fact that many modern communication systems cannot communicate with each other across something as simple as the public safety services in NYC.

 

[Goliath]

I don't know enough about radio to say, one way or another.

If worse comes to worst, you could always just say that the Florida's wireless had been disabled by the effects of passing through the time-warp.

 

[Plecostomus]

...by coincidence the same reason the Gemini can't pound the shit out of the Florida with it's missile battery.

 

[J.T.B.]

I agree with the others, the main battery would sit this one out and let the 5-inchers do the job for which they were intended. By that time the secondary batteries were director-controlled, and I don't know if the FC system could keep up with a 48 kt target, I'm thinking it would be strained. On the other hand, I don't think the patrol boat is going to want to stick around and fight if, what, five or six 5-in guns open up on her. She's not a big craft.

The Gemini is a small ship. A direct hit even passing through would do severe internal damage and result in a kill. I went below decks on the Pegasus years ago and I can remember the lower decks being full of engines.

Agreed, any hit on the hull will either take out vital machinery or compromise the hull enough to put an end to high-speed operating.

The Gemini has no idea what they are up against until they get into visual range by then they are under fire. Also the upper superstructure is unarmored, so the 3" gun could do some damage up top. Seen plenty of examples over the years looking back through the battlehship archives.

Everything that matters on a battleship of that vintage is impervious to 76mm fire, no matter how rapid. They could take out the bridge and even the captain but the XO would just take over inside the conning tower. A lucky shot might take out a director or rangefinder, but to do any accurate shooting the patrol boat is going to be within the range of the 5-in battery.

I don't know if the Florida has radio/wireless at this point in history, and if it does I don't know if they could even hear the Gemini talking to them. That'd leave naval Flag communication, wich is near universal across the ages. This is one of the reasons the Gemini is on appoach when the Florida opens fire.

They definitely have wireless of the key-coded message variety, no talk-between-ships system yet. It's probably totally incompatible with the patrol boat's receiving equipment anyway. Communicating by blinker light in straight Morse is probably the best bet. Semaphore would probably work, but I don't know if Gemini would have a signalman aboard, though a QM might be able to work through it.

--Justin

 

[Plecostomus]

They definitely have wireless of the key-coded message variety, no talk-between-ships system yet. It's probably totally incompatible with the patrol boat's receiving equipment anyway. Communicating by blinker light in straight Morse is probably the best bet. Semaphore would probably work, but I don't know if Gemini would have a signalman aboard, though a QM might be able to work through it.

--Justin

Interesting. I didn't realize a signalman wasn't "standard crew" on a large ship.

 

[Bloodwhiner]

I'm currently reading the scifi/alt history series Axis of Time by John Birmingham. The premise of the trilogy is very similar to this threads proposal but reversed. A multinational battlefleet from 2021 finds itself in dumped into 1942 World War 2.

If you find this thread interesting, that series is worth checking out.

 

[J.T.B.]

Interesting. I didn't realize a signalman wasn't "standard crew" on a large ship.

A large ship, sure, but a patrol boat with 15-20 crew, probably not. A quartermaster or radioman could handle plain Morse code, but all that flag-bag stuff isn't really needed on a vessel that size.

Signalman has since been dis-established as a rating in the USN, I believe their functions have been taken over by quartermasters.

--Justin

 

[Plecostomus]

Ok thanks for clearing that up.

I am reading Axis Of Time right now so hush up no spoilers please.