Design challenge - design the Asama AC

[sabratha]

I found it relatively easy to re-create 1890s battleships as a legacy fleet, but the Asama AC proved a different kettle of fish. Even after making a "cramped" design, I just can't seem to make it work in the game.

So, feel free to post as near similar design as the legacy build allows.

[namuras]

Tried it... not possible. You either have to strip off a lot of armor and run with a small reserve of ammo OR increase the size to around 13.5k tns.

This is what i use as legacy CA:


The secondaries are up for debate. It is either 5" or 6" depending on gunquality.

[sabratha]

Yeah I'm trying to get my head around the design model of the game.

So far, the Battleship design parameters allow me to build realistic historical designs, or planned but incomplete (1910 south dakota etc) ones.

I dunno, it seems to be a bit too easy to build very good and overpowering crusiers in the 1920s, but at the same time impossible to build some of the better RL designs of the late 1890s and early 1900s. The former is more understandable (Washington treat limits in RL, without them perhaps bigger and better crusiers would come) but the latter issue is more troubling. Perhaps the early 1900s crusier design algorithms need a second look at them.

[namuras]

Sept 11, 2015 8:06:45 GMT -6 sabratha said:

Yeah I'm trying to get my head around the design model of the game.

So far, the Battleship design parameters allow me to build realistic historical designs, or planned but incomplete (1910 south dakota etc) ones.

I dunno, it seems to be a bit too easy to build very good and overpowering crusiers in the 1920s, but at the same time impossible to build some of the better RL designs of the late 1890s and early 1900s. The former is more understandable (Washington treat limits in RL, without them perhaps bigger and better crusiers would come) but the latter issue is more troubling. Perhaps the early 1900s crusier design algorithms need a second look at them.

Maybe, but i think that if you would change much in the cruiser designs... they would end up as faster - lesser armed battleships. 
Also regarding the Asama: it is hard to judge wether the 7" belt thinkness....

Edit:



You can fit it... with a narrow belt...

[tmp]

I think the weight calculations may be somewhat off in the game, compared to reality, but then it is a game and so it's probably unfair to expect it to be exact match. It's not limited to just cruisers -- try to build the N3 dreadnought for example (https://en.wikipedia.org/wiki/N3-class_battleship) and it'll exceed the real planned displacement by a considerable amount, even if you go with the low-mid end of the armour values. The deck in particular seems to add lot of weight, but on the other hand the penetration values in the game allow to keep that fairly low and still have decent protection, so it's not too visible in the game designs.

[tmp]

Sept 11, 2015 8:32:45 GMT -6 namuras said:

You can fit it... with a narrow belt...

One thing to take into account, the ship designer includes the weight of ammo and such in the calculations, so it probably wouldn't be out of place to put the "deep load" value in the displacement field, which for Asama was ~10.5k tons. That should give you some more wiggle room.

[namuras]

With 10.5k displacement and narrow belt it is very well possible to get a full load of ammo AND 5 torpedo tubes and some more armor...

[galagagalaxian]

One of the biggest issues with replicating real world ships (especially "legacy" era designs) in RtW is armor thickness.

In the real world, different armor types had differing levels of protection inch-per-inch. 13 Inches of Harvey armor from the early-mid 1890s was worth the same amount of protection as 15 inches of Nickel-Steel armor. 10 inches of Krupp Armor, developed roughly a decade later, was worth about 12 inches of Harvey armor. Later still came Krupp Cemented Armor, which greatly reduced the chances of spalling (the armor shattering into shrapnel fragments) on hits, but otherwise protected about the same as normal Krupp. And this doesn't even go into the potential weight differences between each type of armor.

In Rule the Waves, armor is rated by how many inches of penetration it will stop. The armor research just represents weight savings. So theoretically, this doesn't even represent how thick the armor actually is, just how much protection it offers.

According to a quick Wikipedia check, the two Asama class ships were built as part of a group of six Japanese armored cruisers, along with the Izumo class. According to this the two classes used the same armor scheme, but the Asamas were built using Harvey armor, while the four Izumos used Krupp armor.

Should the Asamas really have a 7" belt in Rule the Waves? Should it have the same level of protection as the Izumos with their 7" belt of Krupp Armor according to its historical statistics? Or should we reduce it an inch or so to represent Harvey armor being weaker? Or should ships with Krupp armor have thicker than listed belts because Krupp armor is a weight saving research in Rule the Waves?

[ccip]

Yeah, that's the way I've come to understand armor in RTW - it's not actual armor thickness that you're "buying", but thickness-in-Krupp-equivalent. That abstracts some of the nuances in the construction of armor belts, but for these early ships, I'd drop anywhere between 15-30% belt thickness if you're doing these "recreations" of ships from the 1890s (well, using 1890s state-of-the-art technology, anyway).

[gornik]

Here is my try:


Full displacement is used (well, I should increase it for 500 ton anyway).  2 meters high belt is treated as narrow in game, I think. Secondaries protection is decreased, as 4x1 6" guns were in shielded mounts. Slight overweight is intended, as that was common problem of that time. Seem that most problematic while recreating such design is armour weight of 4300 ton, as it is twice more than should be (2100 ton according to Suliga handbook).

EDIT: Harvey should have nearly the same weight in "Krupp standard" as its average strength should be 0,9 Krupp (see Alex SAI RJW R&H mod theme in SAI section of forum)

Deck was 2 in thick according to my sources (51 mm)

[ccip]

Well, the armor weight seems to be pointing at the fact that, again, 7" of Krupp equivalent is more than a little much.

My more conservative take on it, which is almost identical except the armor "downgrade" (which is still more protection that most early ACs I see in the game).




IMO, "short range" and "cramped accommodations" doesn't seem to fit Asama's actual role.

[williammiller]

In this application (7" large plate thickness) Harvey nickel steel would rate ~ 0.81 to 0.84 as effective as Krupp Cemented (type A)(KC A), depending upon the type of shell that strikes it; so for a 7" belt the equivalent thickness would be ~ 5.6" to 5.8" of KC A armor. Also, remember that the 7" figure given in most references is for the thickest portion of the belt, the average thickness is likely to be somewhat less.

[namuras]

Considering what has been said in this thread so far:

[Fredrik W]

I would be the first to admit that RTW cannot reproduce every historical ship. Ship design is an incredibly complex subject, and there are a myriad factors that affect a design. Any program will have to make simplifications somewhere. RTW is a game, and it attempts to recreate ship design in the period covered, but it cannot cover every conceivable ship design or variant.

[sabratha]

Yeah, though I thought the Asama would be a particularly vivid example of how much the early game crusiers tend to be under-acheivers in comparisons to actual designs.

But the comment son the narrow belt plus armor varieties, well found those pretty convincing all in all. Plus we could argue about it for some time, but I think it wouldn't be irrational to describe the RL Asama as somewhat top-heavy, hence in game terms making it a slighgtly overweight ship.