Super-Dreanought era secondary doctrine

[spitfire97]

How do you decide what secondaries to arm your ships with in the super-dreadnought era? Looking specifically at the period between the development of dual purpose guns and the obsolescence of the gun ship

On capital ships, do you continue with gun-shield (2in armour) emplacements after 5in and twin DP mounts are developed or do you start to armour them more once reliable training and elevation is available?

On cruisers, topweight very quickly becomes a limiting factor when you want to add deck mounted torpedoes, floatplanes, light and medium AA guns and directors. What's your doctrine regarding heavy AA secondaries on CL and CA class ships?

I don't think there's any one "right" way of doing it, it's a compromise either way, but I'd love to hear what your decision making process is

[ewaldvonkleist]

For secondaries I always use the maximum number of 6in guns in double turrets.
-6in imho one of the best gun calibres in the game
-everything bigger can flashfire and everything smaller has insufficient range to fight DDs near edge of torpedo range
-6in is strong enough to do some damage to DDs and CLs
-you have weight reserve so you can later upgrade to the lighter 5in guns with added DP and/or autoloader weight.

I rarely build cruisers at all and focus on DDs and capital ships.

[kriegsmeister]

I have a multitude of design philosophies when it comes to secondary, tertiary guns, and AA guns that vary in era and available technology.

Destroyers - Never - Your main battery is already your secondary weapon next to torpedos and later missiles, and tertiary is your anti-submarine and mine warfare equipment. I may throw on some LAA/MAA but generally they don't get any anti-air weapons until the DP guns as main battery tech.

Small Cruisers (<6000T) - Almost Never - While 6in guns are pretty much the overall most well rounded caliber, I generally don't use them all that much for cruisers. And when it comes to smaller ships a uniform battery of 4in or 5in is more than adequate for typical CL duties such as raiding, trade protection, and destroyer screening. When DP 3/4in guns come around I might sprinkle a few 3in secondaries on the higher end of these ships but I've found that a uniform 4in DP is a little better than a mixed 5in SP/3in DP until 5in DP comes into play.

Medium Cruisers (6000-12000) - Sometimes 3-5in secondaries - typically armed with 6-8in main guns I like keeping a 3in gap between batteries as it generally allows a 2-to-1 ratio of guns so that the secondary broadside is equal in number to the main battery, but it all boils down to gun quality. I only mount them sometimes though, 1890 start before Destroyers don't need them, small Destroyers will need them because of the accuracy penalty of medium and heavy guns, mid-size Destroyers don't need them, and finally once aircraft become a major threat. I'll even occasionally make 6in DP Cruisers that lack secondaries as well, but +7in will retain them.

Large Cruisers/Battlecruisers (>12000T) - Always 4-5in/Sometimes 6in - mostly dependant on gun quality but these ships will always have some sort of secondary battery. I say sometimes 6in only when you luck out with Q1 before DP guns come into play as the weight savings is better put towards speed since these ships are meant to hunt down the smaller Cruisers with their main battery and 4-5in are more than sufficient for anti-destroyer work.

"Ironclad" Pre-Dreadnoughts (pre heavy gun long barrel tech) - 6-10in sec/3-5in ter - With Q-2 guns you can have some fun and wacky layouts to include having 3 turrets in either AQY or 12Y configurations which I almost always do. Also with Q-2 guns you can have +8in guns in turrets before the true Medium Wing Turret tech which allows you to make some pretty strong ships if you invest in AP tech. But generally I stick to 6-8in guns, whichever is the highest caliber of Q-1, to be the rapid hail of fire and anti-cruiser gun, with 3 or 4in for anti-destroyer work.

True Pre-dreadnoughts - 6in or 7in sec / 3-5in tertiary - once you long Heavy guns and before you get medium wing turrets the choice is quite simple, 6in guns are the most ubiquitous but I encourage people to stop sleeping on the 7in. Yes it does have a flashfire chance, but at the tech levels of the late 90s early 00s it's easy enough to armor them fairly well. Quality for quality the 7in gun is quite strong against Cruisers in comparison to the 6in, and it's also the largest caliber you can get without medium wing tech. And of course you need a good amount of small 3-5in anti-destroyer guns as this is when they start being truly deadly.

Semi-Dreadnoughts - 8in, 9in, or 11in sec / 3-5in tert - Don't use 10in guns, they are statistically inferior to 9in and 11in unless you have at least a 2 stage difference in quality. Other than that, I actually don't build a lot of semi-dreads preferring to stick with a 7in secondary battery unless there is a higher quality bigger gun. When I get Medium wing turrets I tend to invest in a bunch of Blücher style armored Cruisers since a uniform 8in or 9in battery can actually beat out a mixed battery of a battleship due to accuracy mechanics. But always obligatory 3-5in anti-destroyer battery.

1st Generation Dreadnoughts (<25000T) - 3in or 4in maybe 5in sec, no tertiary - Give all the big guns, don't waste any tonnage on cruiser guns. I typically wait until I have both 3 centerline and Heavy wing turret techs to get at least an 8gun broadside. If you are playing a slow tech game and have a significant time gap between those two aforementioned techs you could build them as a super-semi-dreadnought with a C or X turret (all other centerline turrets have penalties to turrets secondaries) just to have more big guns. But really all you need is your trusty 3-5in battery.

2nd Generation Dreadnoughts, 1st Generation Super-Dreadnoughts - 5 or 6in battery sec, no tert until later refitted - plain and simple, at this point Destroyers are typically large enough to not have an accuracy penalty so just cram in as many 6in guns or if you have better quality 5in's then use those. You usually have a few years until aircraft become a problem but it's easy enough to drop a handful of secondaries to add in some 3in or 4in tertiaries.

Late-Dreadnought Refits and Fast Battleships - 4in or 5in DP - Super easy answer here, DP 5in guns or 4in if you're lagging in tech or when you get autoloaders. 5in DP is the best HAA, 4in is a close second, 6in is mediocre and would be fine if it was unlocked before aircraft were a serious threat but that's not how it goes. If you are still awash in empty tonnage throw on some 3in as well, especially after the improved tech that removes their penalty for mixed AA batteries

Super-Battleships (>50000T) - 6-8in sec / 4-5in tertiary - Big and impractical if you're playing with aircraft but if you do build them they can easily bring in a 6in battery with a tertiary DP battery without eating too much weight to make killing long range torpedo carrying Destroyers and Cruisers a little easier then your massive +16in guns. At this time Fire control tech will help counteract the penalties for mixed medium-heavy guns firing on a target so 7in and 8in are also pretty viable. Although posing a flashfire risk, large enough ships can actually survive a secondary flashfire or 2.

As for Armor.
3in guns are never armored
4in are sometimes armored as a main gun on small Cruisers and sometimes on late dreadnoughts/fastzbattleships, but mostly unarmored
5in are 50/50 unarmored or 2in splinter proof
6in are 50/50 2in splinter proof or 2.5-4in in triple or quad turrets
7in and higher generally get ~2/3 caliber armor

[t3rm1dor]

I think there is an issue with your post, ship guns don't become obsolete in RTW 3

In realtion to the 20s-30s, I am part of the 5 inch church when they are DP available, unprotected always to save weigth. If DP is limited to 3-4 inches or auto loaders come to play, a limited 6-7 inch battery 2 inch armor is what I prefer for DD defence. I don't think secondaries are needed for cruisers in big ships, extra main battery ammo seems preferable over more 6 inch weapons, and 4 inch provide close in protection.

[Nicholas]

I'll make this brief. BBs and BCs get 6 inch secondary guns up until DP 5 inch guns are available. The 6 inch secondaries are initially in casemates protected by as much armor I can shove in up to 6 inches of armor before being built/refitted into single gun-shields and then twin gun mounts with 6 inches of armor when the ROF penalty is removed. 5 inch DP guns get 5 inches of armor.
CAs in the 1910s are armoured cruisers with 6 inch casemates. CAs in the 1920s and beyond are heavy cruisers with DP secondaries.
CLs get 4 inch guns, if I decide to build them at all.
DDs get the largest guns I can fit on them without ROF issues until I can design them with a DP main battery sometime around the mid 1920s.