VGAS, Vertical Gun for Advanced Ships.

[apparition13]

I find myself quite frustrated that AGS replaced VGAS. VGAS with an 5"/127mm gun makes more sense to me than AGS does. You would still have direct fire, but the VGAS module itself is a much more flexible piece of kit that can go in any ship with the space for a 64 cell Mk41 module, so you don't need to develop a special ship to carry a special gun, you can deploy it on existing ships like the Spruance family, and even on Burkes. I've also had difficulty finding information on the system, so if anyone has additional details or information please post them to here.

View attachment 672458
VGAS

Anyone else find this illustration confusing? It looks like it is mislabeled. The side that says 20' looks like the 29' side and the side that says 29' looks like the 20' side. A single gun module size of 10'x29' (roughly 3mx9m) looks like it makes more sense than the alternate arrangement, so I wonder whether it is mislabeled or the illustrator got it wrong.

It also looks as if it is two separate modules in one 64 cell vls space, so you could perhaps do a 32 cell vls and a single vgas gun side by side in one 64 cell modules space. That would be useful as well. It could work as a Spruance refit, with the 32 vls cells used like in the Japanese DDs with 16 VL-ASROC and 64 ESSM on one side and 700 LRLAP, or better yet a multi-purpose round that can attack ships as well, on the other. You could do the same with the rear module on a Burke to make an ASW specialized or general purpose variant, depending on the loadout for the forward 32 cell module. VGAS really is such a missed opportunity.

By the way, does anyone know what kind of muzzle velocities were anticipated, and what the fire rate was supposed to be? I wonder if it might be practical to develop AAW rounds as well if the velocities are high enough. You could use it as a first stage for a slightly narrower and shorter Barak-1, or an ADATS with a different seeker, if you want terminal maneuvering. CAAM is about a meter too long and like Barak-1 a little too wide, but perhaps a 2/3rds length and narrower CAAM could also work. A 32 cell space carrying 700 AAW rounds would certainly increase magazine depth, even if fire rate dropped to 12 per minute from one per second, assuming the initial AGS rate is the same as the VGAS rate, even though I'd think VGAS would fire faster given how much easier it would be to load or even cool the barrel should that be necessary. Go with two modules and you could be at one per 2 seconds.

You could have SM-3 and SM-6 for theater range, VGAS for area defense replacing SM-2 and ESSM, and RAM or 76mm David/Strales for terminal when you need a really high rate of fire.

So many possibilities foregone. Pitch it as a retrofittable system and Congress might bite. If the Zumwalt with VGAS program gets too expensive the Spruances with VGAS could be kept around a while, while VGAS Burkes are built until a CGBL or super-Burke along the lines of Sejong the Great or Atago could be built as a fall back to DDX and CGX.

 

[Nik]

Without having to 'train' the loader system, with water-cooled jacket, perhaps with two- or, yes, three-port 'revolver' system to allow one loading, one firing and one 'alternate', could be very fast...

What's 'rate of fire' on those big 'mortars' ? The 'salvo & scoot' variety ??

 

[apparition13]

Patria NEMO says 10 rpm, and is the single barrelled version of the double barrelled AMOS, which I've seen at as high as 24 rpm, but both are turreted with full elevation and traverse, and the end fire rate is about the same per barrel as AGS. The other automatic mortar systems I've run across have lower rates of fire, but they aren't fixed like VGAS is, so they have more complicated loading. Mortars aren't really my thing though, so someone else may have a better idea.

Perhaps a tank autoloader with the rounds mounted in a turret bustle might be a better model? What kind of fire rate can you get from those?

A pair of 155mm revolver cannon with active cooling might be able to hit VLS launch rates, although I don't know how long they could sustain that rate of fire. On the other hand such a system would have several times the magazine capacity, so if the maximum rate of fire could be sustained for a minute or so that's enough time to burn through most ships VLS loadouts, at which point a v-gun system would still be able to keep fighting, even if it had to be a lower rate of fire due to heating.

 

[apparition13]

By the by, it seems to me that a V-gun would be the ideal mount for a railgun. Without having to worry about barrel droop or elevation, you could build a very thick barrel with a replaceable liner, which should help with barrel life. For that ideal 80 degree launch angle*, use stabilizing fins to tilt the ship toward the target.

*As I recall, and correct me if I am wrong which I may well be, the reasons were to minimize loss of speed from drag due to maneuvering from 90 degrees towards the target and from atmospheric drag by getting high as quickly as possible, and 80 degrees or so is the sweet spot that minimizes the combined drag from both sources.

 

[Nik]

I take it proposed vertical gun system had a rather large minimum range ??

By analogy with eg bomb & shell fuses that 'stayed safe' until they'd spun enough to unwind and arm ??

 

[TomS]

I take it proposed vertical gun system had a rather large minimum range ??

By analogy with eg bomb & shell fuses that 'stayed safe' until they'd spun enough to unwind and arm ??

Really long minimum time of flight, certainly. Not sure about minimum range. You can do a straight up and straight back down trajectory.

 

[apparition13]

I believe you could vary the charge, but I don't know what degree of difference that would make. On the other hand, if you have a visual that's what the 5"/127mm gun would be for.

 

[Firefinder]

Here an fully image of the VGAS picture I found somewhere years back.

 

[TomS]

Here an fully image of the VGAS picture I found somewhere years back.

In one or another thread it was pointed out that the length and width dimensions here appear to have been reversed, but the general configuration is clear enough.

 

[MadRat]

Seems like you could mate SDB-I to attack fixed targets cheaper than most of the smart AGS proposals. If they need to hit moving targets at 100km, there are quite a few cheaper options. They should have kept it K-I-S-S.

 

[Moose]

Seems like you could mate SDB-I to attack fixed targets cheaper than most of the smart AGS proposals. If they need to hit moving targets at 100km, there are quite a few cheaper options. They should have kept it K-I-S-S.

SDB didn't exist when VGAS was being seriously looked at, neither did GMLRS. The Arsenal Ship and other concepts took a look at the MLRS system, but only ATACMS seemed to be appealing. Navalizing the system, and ATACMS, lost out to gun-based concepts on the grounds of affordability (whoops) and magazine size.

 

[MadRat]

VGAS is a viable concept for gunboat diplomacy. Seems like they need to get away from one-size fits all frigates and destroyers for the fleet. I cannot imagine they need more than a few dozen of these gun systems across the global fleet. Why park a $2 billion dollar ship off a coast for bombardment when you could mount these on a cutter-sized vessel at much less cost? Seems not so smart to get within 100km of any nation with a heavy focus on drone technology.

More focus on the mission and magazine size. Gunboat diplomacy was built in the age of sail using ships rarely reaching 300 foot lengths. Good for taxpayers, bad for contractors I'm sure. But affordable at the time when budgets were anemic. Over-indulging in uniform designs makes them unaffordable. Rejecting VGAS because it didn't fit a congressman's idea for a Arleigh Burke or Spruance seems short-side with respect to VGAS. But scale back to more of a Fletcher displacement and give it a scaled down role, its certainly plausible.

 

[TomS]

VGAS is a viable concept for gunboat diplomacy. Seems like they need to get away from one-size fits all frigates and destroyers for the fleet. I cannot imagine they need more than a few dozen of these gun systems across the global fleet. Why park a $2 billion dollar ship off a coast for bombardment when you could mount these on a cutter-sized vessel at much less cost? Seems not so smart to get within 100km of any nation with a heavy focus on drone technology.

More focus on the mission and magazine size. Gunboat diplomacy was built in the age of sail using ships rarely reaching 300 foot lengths. Good for taxpayers, bad for contractors I'm sure. But affordable at the time when budgets were anemic. Over-indulging in uniform designs makes them unaffordable. Rejecting VGAS because it didn't fit a congressman's idea for a Arleigh Burke or Spruance seems short-side with respect to VGAS. But scale back to more of a Fletcher displacement and give it a scaled down role, its certainly plausible.

I think you've got this reversed, to be honest. The closest analog to "gunboat diplomacy" in the modern era are limited objective/short duration strikes at strategic targets in the victim country (e.g., Syria, Libya, possibly Iran, etc.) . For that, you want cruise missiles and aircraft, because they can range wherever they need to go inside the target country and can reliably knock out headquarters buildings, weapon storage facilities, leadership bunkers, hardened aircraft shelters, etc. The sort of things the US hits when it's "making a point" rather than going for an all-out invasion. For that, you want general-purpose surface combatants and at least "lightning carriers" if not the full thing. And we do it rarely enough that we can generally manage to put a carrier strike group on target when its called for. But such strikes rarely are sustained long enough to seriously deplete our weapon inventories.

VGAS was actually intended for something that we don't see very much at all these days -- direct support of an opposed amphibious landing. And for that, the task really does call for a high-mix ship, because you're going to have to loiter deep inside an enemy's access denial architecture -- mines, cruise missiles, drones, coastal subs, the works. You sit maybe 25 miles offshore, to give adequate warning of missiles and aircraft coming your way, to be in deep enough water to avoid the worst of the mine threat, and so forth. You need the remaining 60-75 miles to support troops maneuvering inland and to counterbattery artillery ranging on their landing zones. And you need a ship with competant sensors and self-defense weapons, to avoid being Moskva'd.

I do agree that you don't need a ton of those ships, maybe one per LHA/LHD. But it's not a task you can reliably leave to a bare bones gunboat. And unfortunately, that means it's hard to build those in parallel with other high-mix ships like BMD cruisers.

 

[Firefinder]

And unfortunately, that means it's hard to build those in parallel with other high-mix ships like BMD cruisers.

Which is why the VGAS was that design

You were to put the thing in the same spot that a Mk41 VLS 61/64 count block was with no major modifications.

Allowing a quick change of typing at tge yard.

Need more fire support ships? Just buy more VGAS blocks and put them inplace of the VLS. And vice-versa for the vls.

Apparently there was plans for them being able to switch them out at well equip yards. Allowing you to change say the Kidd from a VLS ship to a VGAS ship and back as needed.

 

[TomS]

You were to put the thing in the same spot that a Mk41 VLS 61/64 count block was with no major modifications.

Ideally, yes. A DDG-51 with VGAS aft would be an interesting ship, for sure. Just enough VLS forward for self-defense once, ESSM quadpack became an option.

Apparently there was plans for them being able to switch them out at well equip yards. Allowing you to change say the Kidd from a VLS ship to a VGAS ship and back as needed.

I am highly skeptical of that. Yes, the 61/64-cell VLS block is technically an SSES B Module, but if you look at how it's fitted in real ships, it's pretty integral to the hull when all is said and done.

 

[that_person]

And unfortunately, that means it's hard to build those in parallel with other high-mix ships like BMD cruisers.

Which is why the VGAS was that design

You were to put the thing in the same spot that a Mk41 VLS 61/64 count block was with no major modifications.

Allowing a quick change of typing at tge yard.

Need more fire support ships? Just buy more VGAS blocks and put them inplace of the VLS. And vice-versa for the vls.

Apparently there was plans for them being able to switch them out at well equip yards. Allowing you to change say the Kidd from a VLS ship to a VGAS ship and back as needed.

What’s your source for the VGAS and Mk41 cells being interchangeable?

 

[apparition13]

I am highly skeptical of that. Yes, the 61/64-cell VLS block is technically an SSES B Module, but if you look at how it's fitted in real ships, it's pretty integral to the hull when all is said and done.

There was a plan to develop a modular Burke hull: https://www.secretprojects.co.uk/threads/mark-71-mclwgs-enters-service.38293/post-501264
with not just swappable mk41 modules but hangars, guns, superstructure, etc. as well. There would have been a 300 ton penalty to make the ship fully modular so the USN decided not to go that route (a mistake in my book), but it demonstrates that a VGAS module could theoretically be made to be swappable. The nice thing then would be you could upgrade the shells (ramjets come to mind) or even the guns, to liquid propellant or even railguns, and simply swap the module.

Personally I think it would make the most sense to put them on San Antonio class LPDs. Along with some extra mk41s with quad packed ESSMs for self defense.

 

[TomS]

Personally I think it would make the most sense to put them on San Antonio class LPDs. Along with some extra mk41s with quad packed ESSMs for self defense

In theory, putting it on an amphibian might make sense. (The same logic applied to the 5-inch guns on the Tarawas, though, and that proved to be a dumb idea).

But LPD-17 as designed only has room for 16 VLS cells, if you tear out the gym that was built there when the VLS was omitted. There is not enough space for a full VGAS SSES-B module.

 

[MadRat]

LCS types make more sense than an LPD, but thats overkill IMHO. It makes less sense to move an LPD within 100km of shore for bombardment than a sophisticated missile frigate or cruiser. I would stick to medium to high endurance cutters aimed at 90 day deployments. They are much less costly to lose, but enjoy a high degree of utility. While not using VGAS they would serve numerous duties in support of fleet operation at a steep discount over Class I survivable designs. Big enough for VGAS and ESSM containers, too.

 

[TomS]

It makes less sense to move an LPD within 100km of shore for bombardment than a sophisticated missile frigate or cruiser.

At the time that VGAS was a serious thing, the LPDs would be pressing in anyway to launch amtracks. And they were thinking about a fairly sophisticated self-defense capability for them (Project Akcita, later just SSDS Mk 2)

 

[jsport]

Study: U.S. Will Run Out of Anti-Ship Missiles in a Fight With China

America's military possesses sophisticated precision weapons, but it doesn't have enough of them for a major naval conflict with China, accord...

maritime-executive.com

The U.S. Army, realizing that its ammunition production rate is too low for sustained warfare, plans to increase artillery shell output at its arsenals by 500 percent by 2025. According to CSIS, U.S. naval forces may have to make similar supply chain investments in order to deter, fight and win. After examining U.S. defense stockpile data and running two dozen wargame simulations, CSIS' experts concluded that the most important American missile stocks would be gone in a week of combat in a Taiwan Strait invasion scenario.

how is this solved w/o reintroducing VGAS?

 

[apparition13]

VGAS still suffers from the range problem, in that it is outranged by missiles. Multi-year contracts for thousands of missiles would bring costs down considerably.

However -

If we want to talk about "biggest mistakes in military research", I'd put not continuing down the SAM-N-8 Zeus guided shell of the late '40s path on that list. We are just now at the point where Vulcano and DART shells are getting close to the accuracy of missiles; imagine where we could be had guided shells undergone more intensive development in the intervening 60-70 years. What I'm picturing is the 5"/54 mark 66 dual gun with a combined fire rate of 96 rpm slinging guided AA munitions, and mk 71 8" guns firing ramjet shells out past 100nm.

And if we're talking VGAS, they can be built with significantly longer barrels since you don't have to worry about barrel droop, which would up the range even more since the launch velocities would be significantly higher. Rate of fire should also be higher due to much simplified feed systems that don't have to take barrel elevation or spinning mounts into account.

We could also be talking about evguns, which is a term I've made up for vertical electro-magnetic guns. This could really benefit rail guns since the rails could be clamped and reinforced from the outside to keep them from flying apart for longer. And of course longer rails would mean higher velocities and longer ranges.

The ultimate picture here would be something like the 76 super rapide with DART for close in defense, Mk66 for intermediate defense, vulcano type rounds for both for surface threats, and vertical guns for extreme range gunfire against surface targets on land or sea. On surface ships Missiles would be limited to ASROC types, for extreme range air-defense/BMD, and maybe cruise missiles to strike hundreds of miles inland. Although for deep strike I think bombers would be able to deliver more missiles over time for anything other than a single strike, since they can go back to base and reload much faster than naval assets can.

Lots of bombers. As in B52 production levels of bombers.

 

[jsport]

VGAS still suffers from the range problem, in that it is outranged by missiles. Multi-year contracts for thousands of missiles would bring costs down considerably.

However -

If we want to talk about "biggest mistakes in military research", I'd put not continuing down the SAM-N-8 Zeus guided shell of the late '40s path on that list. We are just now at the point where Vulcano and DART shells are getting close to the accuracy of missiles; imagine where we could be had guided shells undergone more intensive development in the intervening 60-70 years. What I'm picturing is the 5"/54 mark 66 dual gun with a combined fire rate of 96 rpm slinging guided AA munitions, and mk 71 8" guns firing ramjet shells out past 100nm.

mk 71 8" guns firing ramjet shells

is engineering understood to have already completed, just needs intent

And if we're talking VGAS, they can be built with significantly longer barrels since you don't have to worry about barrel droop, which would up the range even more since the launch velocities would be significantly higher. Rate of fire should also be higher due to much simplified feed systems that don't have to take barrel elevation or spinning mounts into account.

We could also be talking about evguns, which is a term I've made up for vertical electro-magnetic guns. This could really benefit rail guns since the rails could be clamped and reinforced from the outside to keep them from flying apart for longer. And of course longer rails would mean higher velocities and longer ranges.

guessing completely vertical configured EMRG would be less suseptible to asymmetric warping, although would argue w/ modern energetics could get the range of up to 8" rd where one wants.

Although for deep strike I think bombers would be able to deliver more missiles over time for anything other than a single strike, since they can go back to base and reload much faster than naval assets can.

Lots of bombers. As in B52 production levels of bombers.

Problem stealth is becoming less & less effective over time whereas Russia already claims to be on the 1000mile rg SAM, much disappointment on the B-21 being smaller than the B-2 as well as the few being purchased.

 

[Brickmuppet]

I do not know what the muzzle velocity of AGS is, but it was intended to act like a first stage of a missile, so firing something like a shock proofed folding fin weapon with capability and form factor equivalent to that claimed for the currently under-development Peregrine Missile might be able to utilize the missile at close to its maximum air launch range.

Peregrine is about 150-155 mm in diameter and while it's longer than a normal 6ish inch shell, I have no idea how long the AGS "shell" (really a missile) was.

Peregrine is advertised as having a range "comparable" to AIM-120 so 50-90 miles maybe.

1400 rounds is a very deep magazine. (35 minutes at 40 rounds per minute)

OTOH, depending on the price point for Peregrine, a full load out might cost more than the ship.

Fitting one in the 64 cell launch nest on a 'Burke would still leave 32 cells for SSMs and ASW weapons.

 

[MadRat]

I believe they calculated sustained 10 shells per minute and peak burst of 16 shells in a minute. You really are trying to get the shell to 40,000 feet with enough energy to rotate into the z-plane. That was simulated in supercomputers to reach 100km with 127mm and 152mm shells. For one 203mm shell you can have two 152mm or five 127mm in your magazine. I think you commit to 152mm and live with its lower magazine capacity, as it gives you more volume for your shell's brain until you perfect the technology. These won't really be smart, just more or less they will be controlled by simplified controls literally receiving their programming as they leave the barrel.

Once you miniaturize everything, and you gain reasonable expertise, you probably get the the point where you start looking at 105mm and 76mm options. If you can walk a 76mm onto a target's head you've just made most of your existing tube-based artillery obsolete overnight. A direct hit on most MBTs by a 76mm shell would have devestating consequences.

 

[Colonial-Marine]

If you're hitting it from above sure, but you've also got to account for targets like bunkers, buildings, and bridges which even with high precision are going to require a significant amount of high explosive to put out of action. I'd figure 155mm (or 152mm) is about the minimum.

Besides for more realistic expectations and better management which the Army has managed with their guided 155mm projectile programs the Navy would also need to firmly commit to such a program. I don't think a mere three destroyers as what the DDG-1000 program was reduced to was ever enough.

 

[MadRat]

I don't think VGAS is standalone weapon. Its just meant originally for relatively sustainable and functional (not so much cheaper or better) dispersal of ordnance at range.

 

[publiusr]

Maybe put Bull's HARP back out to sea? Store upright in a shrouded superstructure gap?

 

[MadRat]

HARP was a 100 pound projectile, not really similar except for shooting towards the sky.

VGAS is putting a robotically operated pair of vertically-aimed guns fed by a robotic magazine. You don't need the 82 foot long barrel and 3/4 tons of explosive each shot, and its meant to be sustainable. HARP was strictly for experiments. VGAS would be a relatively cheap way to lay down the law across more than 60% of the developed world around the globe, as a vast supermajority lies within 100km of coastlines.. The other 40% of the developed world probably takes a different approach.

The exit velocity is pretty key to VGAS. To ramp it up past the 152mm would require a great deal of more power to reach that 100km, so you either decrease your throw-weight, increase energy per firing, or live with your drop in exit velocity and add more rocket-power. You really don't want to drop that velocity down. And to increase energy you are best to add to the caliber rather than just throwing more power at a lower caliber. But by increasing caliber or adding to the charge either wears out your barrel faster or adds a lot more weight to the system. Likewise, increasing the rocket motors adds great weight and volume per firing. So they set out to use 127mm and 152mm for good reasons.

 

[apparition13]

HARP was a 100 pound projectile, not really similar except for shooting towards the sky.

VGAS is putting a robotically operated pair of vertically-aimed guns fed by a robotic magazine. You don't need the 82 foot long barrel and 3/4 tons of explosive each shot, and its meant to be sustainable. HARP was strictly for experiments. VGAS would be a relatively cheap way to lay down the law across more than 60% of the developed world around the globe, as a vast supermajority lies within 100km of coastlines.. The other 40% of the developed world probably takes a different approach.

The exit velocity is pretty key to VGAS. To ramp it up past the 152mm would require a great deal of more power to reach that 100km, so you either decrease your throw-weight, increase energy per firing, or live with your drop in exit velocity and add more rocket-power. You really don't want to drop that velocity down. And to increase energy you are best to add to the caliber rather than just throwing more power at a lower caliber. But by increasing caliber or adding to the charge either wears out your barrel faster or adds a lot more weight to the system. Likewise, increasing the rocket motors adds great weight and volume per firing. So they set out to use 127mm and 152mm for good reasons.

LRLAP was 220 pounds, about twice a regular 155mm round. The planned ballistic round was 200. The standard USN 8" naval rounds during WW2 was 260 (the superheavy AP was 335). The AGS/VGAS rounds were much closer in weight to 203mm shells than 155mm. They are also much longer. LRLAP was 88.28 in/224.2cm vs. 33.8 in/858mm.

The planned range was 100nm. AGS didn't reach that, but if the VGAS barrels were longer it might be achievable.

 

[MadRat]

I've seen 100nm, but after looking around there is 100km in different sources. Obviously 100nm is much longer than 100km. But with sources giving mixed numbers I conservatively stuck to the lower range. While a 152mm VGAS round may be more similar to a NATO 203mm, if you want a 203mm VGAS round you have similar scaling. Unfortunately you also drop in exit velocity with less gas sealing involved with larger rounds. Impulse physics work against the larger round, too.

 

[jsport]

https://core.ac.uk/download/pdf/323315511.pdf

Research on vibration characteristics of a multi-barrel artillery
Yingfeng Wu1 , Qingsi Cheng2 , Guolai Yang3 , Jinsong Dai4 1, 3, 4School of Mechanics, Nanjing University of Science and Technology, Nanjing, 210094, China 2Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle, Hubei University of Arts and Science, Xiangyang, 441053, China 2Corresponding author E-mail: 1wuyingfeng911@126.com, 2chengqingsi@hotmail.com, 3 yyanggl@njust.edu.cn, 4djs101@163.com

As a new type of artillery, the multi-barrel artillery has the advantages of high firing frequency, efficient mutilate ability, largest kill area, et al. which make it a hotspot in present research on artillery field. Compared with single-barrel weapons, the multi-barrel artillery has a more complicated yet richer structure, thus the vibration caused by the interaction with a high-speed moving projectile is also more complex. The vibration of barrel has a significant effect on firing accuracy, which has been a classical problem concerned for long time due to particularity of the shock excitation and complexity of the mechanism system [1-5].

 

[Scott Kenny]

I mean, for a VGAS ship (I keep wanting to pronounce that like Las Vegas, "vay-gus" not like "Vee-gas"), you need at least one per amphib group as your basic force construction.

Based on Zumwalt planned production, the idea was to have more like 3 VGAS ships per ARG: with 9ish ARGs (3 always deployed, so there are 3 more in refit and 3 more in workups), 9x3=27 ships and 5 "loose" Zumwalts to show the flag elsewhere (1.67 always deployed). This is probably so that one VGAS ship can be firing, one reloading in a local friendly-ish port, and one en route between, but that is a guess. (You'd also want a CG and a couple of DDGs around for air defense, but that's a separate discussion)

I think the lesson with Burkes is that you should spend the tonnage to make whatever major systems you choose modular, so that if you need to pull out the 64-cell Mk41 block you can.


=====
I remember that one of the issues with the early vertical gun proposals was a 20+km minimum range, based on the turn radius of the shells at altitude. This meant that you needed a conventional gun turret to engage anything close, which defeated the purpose of a vertical gun for stealth. This may have been addressed in the M982 Excalibur development, since one of the software upgrades they talk about is trajectory shaping so that the shell can come in at odd angles.

Also, one notable downside for the vertical gun is barrel length. Unless you either add a deck level or allow the barrel to protrude from the existing deck, you're limited to a barrel length of about 20ft (7ft long shells, 27ft deep module block). That's roughly an L39 barrel, surprisingly short. With a turret, you can have a 30ft barrel, roughly L60. That allows you a lot more initial velocity in the gun and less need of the rocket booster after.

 

[Firefinder]

Also, one notable downside for the vertical gun is barrel length. Unless you either add a deck level or allow the barrel to protrude from the existing deck, you're limited to a barrel length of about 20ft (7ft long shells, 27ft deep module block). That's roughly an L39 barrel, surprisingly short. With a turret, you can have a 30ft barrel, roughly L60. That allows you a lot more initial velocity in the gun and less need of the rocket booster after.

Expect for this the Gun was going to pop up and down for loading.

Meaning you only needed a 4 foot tall by 3 foot across deck house shaped like the Monitor conning tower.

Resulting in basically in basically a bump compare to a turret.

Or something like the Seawolf/Sea Ceptor vls set up on Royal Navy ships.

Aint much reason to put up an entire deck when you can just put a covering structure around it.

 

[Scott Kenny]

Expect for this the Gun was going to pop up and down for loading.

Meaning you only needed a 4 foot tall by 3 foot across deck house shaped like the Monitor conning tower.

Resulting in basically in basically a bump compare to a turret.

Or something like the Seawolf/Sea Ceptor vls set up on Royal Navy ships.

Aint much reason to put up an entire deck when you can just put a covering structure around it.

"Add a deck level" was my shorthand for "build some structure above the main deck"