Engineering Options

[potrero]

Having recently been going down a deep rabbithole on design choices of various warships between 1905 and 1915, I had a thought about something to add some depth to ship design.  How about including a drop-down menu to pick the type of machinery your ship will run on.  Options would be vertical triple-expansion, direct-drive turbines, geared turbines, turboelectric drive, and marine diesels (for however many different major types of diesel machinery there were--not my area of expertise).  VTE would be the only option available at the start of the game, with the rest unlocked via research, and each has pros and cons.  Whatever you decide to go with, that's what the class is stuck with for the duration.  Replacing the machinery won't change it, though it will probably improve reliability.

Direct-drive turbines will be more expensive and more likely to develop engine problems requiring yard time, and poorer fuel economy, meaning greater tonnage increase necessary for medium/long range.  They will also have slower acceleration than turboelectric propulsion due to the necessity to build steam pressure.  The tradeoff will be better high-speed performance, and they should be available several years at least before geared turbines.  

Geared turbines will initially be even less reliable that direct-drives and share their slower speed changes, but will drastically improve their fuel economy, being a more fuel-efficient option than direct-drive or VTE for a long-range ship.  Machinery research will incrementally improve their reliability until they become your best overall option, but also the most expensive (you get what you pay for).

Turboelectric drive, once unlocked, will have the advantages of good fuel economy (not as good as improved tiers of geared turbines), the shortest time needed to increase speed, and the least vulnerability to being knocked out by penetrating hits due to their redundancy.  The drawback will be that they are good for ships designed for 20-25 knots (Standard-Type battleships), but need too much additional tonnage to be a really good option for anything faster.

Diesels will sip fuel for long-range cruising, but have substantial speed and tonnage restrictions.

VTE will be lower-maintenance until turbine technology matures, and will be the cheapest option.  However, its power-to-tonnage ratio is craptastic.  It can't maintain prolonged high-speed runs until forced lubrication is developed, and its reliability advantage will eventually be surpassed by turbines.  Additionally, the large internal volume required by VTE machinery will limit your centerline gun mounting options on smaller (relatively speaking) capital ships (CA, BC, BB).  Designs will have to be larger in order to accommodate midships centerline barbettes and magazines alongside propulsion machinery.  This should probably also be affected by the design speed, i.e. a faster ship needs more machinery space (hey, battlecruiser design paradigm! ), so a table would probably have to be worked out.

Possible VTE values:
Under 18,000 tons:                          A, B, X, Y, and wing mounts only
18-21,000 tons, under 21 kts:           A, B, C, R, X, Y, and wing mounts
18-21,000 tons, over 21 kts:             A, B, X, Y, and wing mounts only
21-24,000 tons, under 23 kts:           A, B, C, Q, R, X, Y, and wing mounts
21-25,000 tons, over 23 kts:             A, B, C, R, X, Y, and wing mounts
Over 25,000 tons, under 24 knots:    All mounts available
25-30,000 tons, over 24 knots:         A, B, C, Q, R, X, Y, and wing mounts
Over 30,000 tons:                            All mounts available

These values are just a basic idea of what I have in mind.  Somebody who knows more about engineering may feel free to provide more realistic values.

The goal of all of this would be to throw in another layer of considerations in designing your ships.  Players will have to configure their ships according to available technology, much as the designers of the Kawachi, Helgoland, and Nassau classes did.  You will need to rely on wing turrets for a heavier broadside if you can't build engines that don't take up all the space you need for centerline mounts.  It wouldn't affect destroyers so much since they don't have armored barbettes, and even when you reach a point where they would probably have shell hoists instead of crew carrying shells topside by hand, their magazines and handling spaces take up a lot less space, and you'll almost certainly have turbines and/or diesels available by then.  Light cruisers would see little effect for mostly the same reasons.

What do y'all think?

[Adseria]

I like the basic idea, but I'm not sure about restricting available turret mounts based on the engine type, it feels like it's getting a bit too into the intricate details of the internal ship layout. I'd prefer being able to build my ship however I like, and RPing this kind of limitation. Also, I think that it should be possible to rebuild to different engine types, since engine rebuilds in the game effectively involve stripping the ship down past the armoured deck, removing the existing engines, adding new ones, then building the upper decks back up.

That said, I do like the general idea. I'd love to see different types of engines, particularly being able to choose reciprocating vs turbines.

[potrero]

Re: machinery replacement, keep in mind that different engine types required substantially different internal layouts. VTEs need lots of vertical depth. Turbines don’t need to be as tall, but they will be at least somewhat long horizontally. Turboelectric plants will be more compartmentalized. Switching out one type of machinery for another means rearranging the guts of the ship, which were designed to take certain loads a certain way to support everything above and around them. Not saying it’s impossible, just that it’s a huge and expensive enterprise to do so for anything with an armored citadel.

I suppose that could be reflected in-game. Replacing machinery would give the option of changing machinery types, but changing it on anything bigger than a destroyer will incur a significant cost and time penalty. So if you’re like me and like to keep your first-gen DDs around in the mothball fleet as wartime sub hunters, you can tear out the VTEs and stick turbines or diesels in them easily enough, but trying to do the same on your 28,000-ton second-gen dreadnought battleship will be slow and expensive enough that new construction really might be a better option.

As for restricting gun mounts, I’ll be honest: I kinda wish the game had a super-detailed ship design mechanic where you could arrange individual compartments, pick boiler types beyond just whether they burn coal or oil, place rangefinders and AA mounts, design more detailed armor schemes, etc. But that’s just me. I recognize that most people probably wouldn’t be interested in playing that game. I figure the gun mount restrictions would add a little bit of the “Springsharp on meth” level of detail I secretly wish for without going too deep or crazy. It’s another set of tradeoffs for designing your ships.

For example: it’s 1910 and I’m laying down a new armored cruiser. I have 4 centerline turrets researched, but not superfiring. Do I go tried-and-true VTE that will be cost-efficient and low maintenance, but will require wing turrets if I want any speed above “glacial?” Or do I try those expensive new direct-drive turbines for a more streamlined gun layout and slimmer citadel at the cost of increased yard time and more fuel tonnage needed to get long range?