Will it build?

[The Land]

So I'm experimenting with the ship builder to try to nail down the issues with propulsion and armour and so on.

At the moment I am looking at the "Armed Convoy Attack" scenario that offers you the chance to build a range of ships around 1900-1906 tech, and conveniently I have a book on the subject to hand (most of my naval history is in storage )

HMS Drake (1901)

First up, I'm looking at HMS Drake - https://en.wikipedia.org/wiki/Drake-class_cruiser

Tl:Dr version: This is pretty easy to build, the main obstacle is that you can't select secondary armament large enough. Also, even accounting for the weight saved by this, the game designer makes it slightly underweight - you can increase the engines to get a 24.5kn ship instead of 23kn. 

I've selected Armoured Cruiser IV, which seems to be an appropriate casemated late Armoured Cruiser. I start by setting the displacement to the correct value of 14,150. This gives dimensions of 427' 8'' x 68' 6'' x 53'6'' - compared to the historical figures of 521' x 71' x 26'.  It's slightly odd that the game has a much shorter ship and slightly less wide ship for the same displacement. Also the draught values are clearly not measuring the same thing. 

Then I set us to the correct speed - 23kn. The game gives 34,000HP against 30,000HP in my source, which is reasonably close. Indeed, multiplying the historical 30,000 by the square root of the length ratios gets to 33,000 so almost bang on accounting for length. I have also selected multiple-expansion engines, which is historically accurate. Also Shaft 1.

For armour I selected Krupp 1 as Krupp armour was pretty much a given in the 1900-1905 period. I did my best to model the armour thicknesses of the historical ship (though it had some tapering on its forward belt which is hard to model). But basically I got something pretty similar. I selected Citadel II, though couldn't quite tell if the lighter Citadel I would also be appropriate based on the descriptions. I also selected "Few" bulkheads - RN cruisers of this vintage had some attention paid to this, but not so much as to stop the Cressy-class ships sinking in minutes after being hit by single torpedos.

Weapons - there are two 9in in turrets fore and aft (not 9.2in); 16x5in (not 6in because the editor doesn't let me add 6in to casemates on this model); and 12x 3in in single or double mountings, vs 14 "12pdr". Plus two torpedo tubes. So that is all pretty good, though I have saved some weight by using 5in not 6in. Weapons options are Cordite 1, Advanced Hydraulics, and Enhanced Reloading. 

Other equipment includes Coincidence Rangefinder I and Advanced Radio. 

Where does all of this end up? 

Well this is 11,884 tons of the 14,150 displacement. 

But wait! The observant among you will have noticed... in the photo I didn't add a funnel! Whoops! 

Now, in the Ship Designer I can add exactly ONE (1) Funnel and it it completely happy and believes it's  a valid ship. However there is an Engine Efficiency Value based on the number of funnels. I have very little clue what this does in game but I assume it's meant to be over 100%. Adding 4 Standard Funnels in line with the historical design gets me to 12,750 tons, or 1,400 light. 560 of this can be explained by the weight difference between 5in and 6in guns if you believe the values in the designer.

So the upshot is:

This design ends up 840 tons too light and 90ft too short.

What can you do with those 840 tons? The most obvious thing is to increase speed. I found I was able to increase speed from 23 knots to 24.5 knots at a cost of 610 tons. Any more and I'd need another funnel, which would be self-defeating. 

 

Edited February 2, 2021 by The Land

[The Land]

Next up, HMS Duke of Edinburgh of 1906 vintage - https://en.wikipedia.org/wiki/Duke_of_Edinburgh-class_cruiser

TLDR:  this ship is impossible to build exactly and comes in 837 tons overweight - 14,337 against a historic displacement of 13,500. Weird stuff happens with the engines and probably armour, plus tower and funnel options mean it's far worse to build. 

This time I'm using Armoured Cruiser V. There is no perfect answer for this ship, which had a mixture of casemates and turrets. Armoured Cruiser V has turrets but no casemates - it makes little difference. 

Dimensions come in at 478 x 84'2 x  58'9'' vs 500' x 73.5' vs 27'. Again the draught figures are non-comparable and must be measuring different things. But the Ship Designer must be working off a lower draught to explain the higher beam it's using. Length is bang on though.

Speed is set to 23.5kn against a historical 23.3kn. However, power gets weird. Power ends up at 37,023HP against historically only 23,000. Which strikes me as odd. Also odd, but differently odd, is the comparison with the Drake attempt above. The ship designer version of Drake is much shorter and slightly heavier than the ship designer of Duke of Edinburgh. Yet the game's version of Drake takes LESS power to reach the same speed. This can only be explained if the Armoured Cruiser V hull is really massively less efficient. Though the CA V Hull has Hull Form 70 vs 65 for CA IV which should make the CA V hull more efficient. Anyone have any clue what's going on here ??

Even more confusing is the weight of machinery. Drake had 2,670t of machinery. Duke of Edinburgh has 2,134. DESPITE having more power, it has less weight of machinery and boilers. Something is very definitely broken here.  Yes I did check - they both have multiple expansion engines and Shaft 1. The Duke does have semi-oil propulsion not coal. BUT that doesn't affect engine weight, only fuel weight. 

Armour - not much to say here, it's pretty similar to Drake. 

Weaponry - I can fit on six 9in turrets to represent the 9.2in main armament. As there are no casemates I must use 6 turrets of 2x5in instead of 10 single 6in. This probably makes the game version slightly too light. Plus there is no space for the historical 22(!) 3-pdr guns (2in, I think). This is all fine, given the engine limitations.

So... WHY is the newer, more modern hull form overweight?

Part of the answer is towers and funnels. The CA V hull has less options for these. You have to select Forward Tower 3 or 4, and Rear Tower 4. Which is fine, but those upgraded towers are WAY heavier: 1300t vs 800t (and on a smaller ship). Also, Compact Funnel Plus Rangefinder is the only available Funnel, working out at  1181t vs 945t  (despite, again, being a smaller ship). That reflects 700t of overweight. Of course, all of those things come with in-game benefits (better spotting! Better accuracy!) and may be a valid game design decision but it's still sort of odd that the newer hull has less options not more (especially having only one kind of funnel on offer).

I assume the other increases in weight come from the fine details of the different armour options. But I cba to look at present. Also, if I selected Coal fuel not Semi-Oil, the Duke of Edinburgh would be 300t more overweight.

Upshot: There are several different things wrong with the weight distribution here. Engines are too light. Towers and Funnels are probably too heavy (or at least lighter options should be available). And that's not the end of the story either.

[Cpt.Hissy]

Draught figures are probably correct, but nearly all ingame hulls are hugely oversized in height, usually over twice as high as they supposed to be, this creates these weird looking numbers.

[The Land]

3 hours ago, Cpt.Hissy said:

Draught figures are probably correct, but nearly all ingame hulls are hugely oversized in height, usually over twice as high as they supposed to be, this creates these weird looking numbers.

oh, interesting.

I'm guessing that's some kind of decision related to the visuals of the game and ships needing to appear larger in the massive waves to be visible? But anyway, it's odd that the draught numbers end up sort of doubling but length and breadth are not in proportion with either the stated figures or half of the stated figures.... 

[The Land]

Next up, HMS Invincible (1906)

Before I should start I should say that I'm not one of those people whose life is ruined if every historic ship can't be exactly built in the editor. That's an unrealistic expectation. My interest here is in troubleshooting what's up with the editor and improving the game. Also, the photo is smaller because of the thread limit or something.

Anyway.. tl:dr. this ship is too easy to build, mainly because turbine propulsion appears to be too efficient. 

Displacement: 17,500 is the minimum for Battlecruiser I, 250 more than historically. I'll live. Dimensions are 520 x 78 x 59 - versus 570 x 78 x 30 historically. The Ship Builder version is 50' shorter *shrugs*. 

Speed I set to 25kn, the true value. The game believes this needs 39,370HP vs the 41,000 historically. I'd call that within the margin of error (though on the wrong length!). This time of course I have Turbines, but I'm still on Shaft I. I seem to need only one Medium Funnel. 

Protection remains Krupp I in the correct thicknesses, the 6in belt is the minimum possible for a battlecruiser, which is fine. I'm also using Anti-Torpedo and Anti-Flooding Measures I unlike in the CA designs. 

Weapons are 4x2 12-in, 5x2 4-in and 2x1 3-in. The secondary armament is a bit too light compared to the original 16 4-in. However most of it is in armoured positions, so the net effect on weight is probably minimal. I have 4 torpedo tubes not the historical 5. 

I have selected Advanced Tower I and Rear Tower V. This is a bit arbitrary (what's the 'right' historical comparison?)

The upshot: 15611 tons against 17500. Maybe 200t is from not having the whole secondary armament, so I am 1700t shot. If I give the ship Advanced Tower II not I then I end up at 16,104.

I can then increase the speed to.... 29.5kn, with a bit of funnel-swapping. Ok, that's nuts. This high-speed variant has 59,600HP which seems correctly in proportion. However, the engine weight goes up from 1,850 to 2,805t. Also in proportion, but... very low for a fast ship.

What's happening? Well, if I select multi-expansion steam then I end up with the ship being basically full at 25kn. Turbines have a 22 Hp per Engine Ton rating while steam has 15.5HP/Engine Ton. In addition Turbines have -8% Engine Weight compared to -4.5%.

Now I don't have any of my really in-depth sources to hand that cover the turbine transition in detail. But I would be willing to bet that turbines were not >50% more efficient per unit of weight. Indeed, the figure that's used for multi-expansion steam engines would look basically the correct figure for first-generation turbines like those mounted in Invincible.