I'll admit I find your idea intriguing, but it doesn't seem like it could fit my current concept very well.

In a "sandbox" game, it would fit (and would even bridge efficiently with my energy system) allowing any ship to become anything.

My concept revolves around hull types that are much more restrictive. I really want to build the lore/feel/gameplay around these specific hulls.

Each faction have few hulls which they can customize a bit, but not too much as to derail them from their original purpose: a science ship can't be turned into a missile frigate, etc.

Each of these hulls should contribute to the overall strengths and weaknesses of their faction and cover some of the basic roles (leave some opened) etc.

As a result, being able to field any amount of weapons on any ship would be too customizable, and though interesting as a system, it wouldn't support the current design I have in place.

To be in-line with my current approach, not only do I need to have specific slots in place, but ideally, these slots should not only be labeled as "weapon", but rather, as a class of weapon I can use in this slot (energy-powered weapons such as beams, for example, would only theoretically require an energy port, whereas missile launchers would require some form of "door" to the inner cargo rooms of the ship and only minimal power). Since each weapon type plays a much different role, I need to limit the amount of customization a player can make to the core craft's functionality without making it too hermetic...

To be in-line with my current approach, not only do I need to have specific slots in place, but ideally, these slots should not only be labeled as "weapon", but rather, as a class of weapon I can use in this slot (energy-powered weapons such as beams, for example, would only theoretically require an energy port, whereas missile launchers would require some form of "door" to the inner cargo rooms of the ship and only minimal power).

But it would make these slots meaningless (no choice at all then, you put beam weapons in beam slots and missile weapons in missile slots). Why not get rid of these slots then? Just say this hull has 6 beam and 2 missile weapons (and the player chooses what specific beam/missile they want from a drop down list).

As a result, being able to field any amount of weapons on any ship would be too customizable,

Not exaclty. The hull can hold 100 beam weapons maximum, and the player decides it will have only 80 and remining 20 "space" will be used for some special module.

You don't need to touch weapons at all here nor give any weapon customization to the player (just modules and ratio of weapons to modules).

General thought, if you want to "limit the amount of customization" slots make no sense, use some different system (the strongest point of slots is customization, no point implementing these if you want low customization).

OK, maybe I will post what I plan to use in my game since it should be compatible.

- you research hulls, each hull is unique (identical to your premise)

- a hull can have X beam weapons, Y torpedoes (missiles), Z fighter bays; you select from a drop down list (or something similar) what kind of beam weapon you want (laser, proton, gauss) and what torpedoes (MRV, antimatter, tracker)

- a hull has 2-3 slots for special modules, you can put there shields, electronics, boosters, etc

- a hull has several standard pieces of equipment (like scanner, targetting computer, ECM, escape pods, communications array, reactor) and you can toogle if you want an advanced version installed (basic/advanced), there either be a hard limit how many advanced pieces you can have (like 3 basic and 2 advanced) and/or advanced one would increase the ship's production cost

- a hull has 3-5 layers of armour (more layers does not necessarily mean more thick, a primitive hull could have one super thick layer only for example), you can choose what these layers (each separately) can be (standard, antiradiation, antineutrino, antimatter absorber), so you can for example go for 2x standard and 1x antiradiation layer (which would be weaker than x3 standard but also protects against radiation weapons)

You have been reading mu threads too much.
By slots I did mean select from a list. I just call it slot because from a logoc perspective it is the same.
I took use the same approach:
x beams y cannons z missiles B fighter hangars

Most ships have up to 3 system upgrades (better thrusters for maneuverability or speed, better sensors, etc.)

Each of these system upgrades are either new modules, or upgrades to pre existing "stock" modules (sensors, generator, engines, etc.)

And thats it: simple as that. But obviously the upgrades vary based on the systems the ship has / hasn't and the weapons actually equipped.

Oh, I see.

My older idea for "limiters"

The ship design is constrained by:

- weight/tonnage (or slots or whatever that represents available space - you always want to fill it 100%)

- energy (trivial, just like you described)

- crew

The crew one is special here and is not working as you would expect. First of all a hull has quite a lot of crew space and in a typical situation it should operate way below max crew limit. The crew here is a strategic resource, you want you fleet as a whole use as few crew as possible (it's a resource shared between all ships, and you can't produce crew, so it kind of limits your total fleet size).

So, when you install modules (like targetting system/weapons) you could either go for fancy computers that use a lot of energy but do not require much crew to operate or manual targetting systems/manual ammo loading/manual cannons operating and that would mean a lot of crew used up.

What to do with excessive energy

Yeah, I was thinking about it too... But couldn't find a great solution :(

I think crew could partially fix it (you install "automatic" modules to use 100% of energy the reactor provides and the rest is filled by "manual" modules), but I'm not so fond on that concept (automatic vs manual).

Another idea is to "damage reactor in battle" and therefore you can't predict how much energy you will have in a battle, so having an excessive energy is a desired safeguard.

Booster for shields (excessive energy multiplies shield's efficiency). With a limit, like unused energy grants maximum +50% boost to shields, to prevent players go crazy with reactors.

Players can manually disable/enable specific components on their ships (shield generators, sensors, even engines!) which allows them to manage power shortage

Manually? That's excessive... Make it simplier, like insufficient energy reduces (not disables) beam weapons rate of fire, shields, combat speed (in equal proportions).

Having more energy allows you to sustain generator damage for sure, and makes you more versatile and mobile, but it is a limited advantage to not using the extra power you have onboard. If you would spent it on weapons or passive defenses instead, you wouldn't need to worry about getting damaged anyway...

A but lame idea: the ship enters combat with random status of the reactor (50%-100%), like if space travel could discharge the reactor temporarily and you can't predict but how much.

(I'm not a fan of this but it should work)

Note not necessarily reactor damage is needed to reduce power available, like power circuits, power lines in the hull, etc could be destroyed making loses in energy.

Another idea, beam weapons overheat the longer the combat lasts and require more power per shot each combat round OR reactor gradually lowers efficiency each combat round (overheated or something).

I feel that such a system would force players to design 'energetic ships' (those with shields and weapons) around a single beam weapon to maximize their lasting power, whereas other ships should maximize power output of their guns/missile launchers.

Maybe you are exaggerating? First the player would try to put a proper reactor to not have excessive energy in the first place. Second, if that's a problem you could simply make beam/shields designs less efficient/more expensive.

Also, do you really see a space ship that would not require energy to operate? Missile launchers should require some energy too, also all these targetting computers, ECMs, communication arrays, combat scanners, etc. In theory, I can see a scenario where a beam weapon ship uses not that much more power that one without these (I mean energy used mostly by non weapon components), althrough I agree it's a bit of stretching the energy rules :D

Players can manually disable/enable specific components on their ships (shield generators, sensors, even engines!) which allows them to manage power shortage

Manually? That's excessive... Make it simplier, like insufficient energy reduces (not disables) beam weapons rate of fire, shields, combat speed (in equal proportions).

Having more energy allows you to sustain generator damage for sure, and makes you more versatile and mobile, but it is a limited advantage to not using the extra power you have onboard. If you would spent it on weapons or passive defenses instead, you wouldn't need to worry about getting damaged anyway...

A but lame idea: the ship enters combat with random status of the reactor (50%-100%), like if space travel could discharge the reactor temporarily and you can't predict but how much.

(I'm not a fan of this but it should work)

Note not necessarily reactor damage is needed to reduce power available, like power circuits, power lines in the hull, etc could be destroyed making loses in energy.

Another idea, beam weapons overheat the longer the combat lasts and require more power per shot each combat round OR reactor gradually lowers efficiency each combat round (overheated or something).

I feel that such a system would force players to design 'energetic ships' (those with shields and weapons) around a single beam weapon to maximize their lasting power, whereas other ships should maximize power output of their guns/missile launchers.

Maybe you are exaggerating? First the player would try to put a proper reactor to not have excessive energy in the first place. Second, if that's a problem you could simply make beam/shields designs less efficient/more expensive.

Also, do you really see a space ship that would not require energy to operate? Missile launchers should require some energy too, also all these targetting computers, ECMs, communication arrays, combat scanners, etc. In theory, I can see a scenario where a beam weapon ship uses not that much more power that one without these (I mean energy used mostly by non weapon components), althrough I agree it's a bit of stretching the energy rules

While I agree that micro-managing every component can be troublesome, I can see value in turning on/off a cloaking device for example. Also, I like the idea that components become less efficient as they take damage, but still consume the same amount of energy. In many cases, turning off a low-producing shield generator to revert all power to weapons or engines may be advisable. I'm trying to come up with something that sums it up more efficiently than a list of on/off switches (like some sort of Bridge Order) but it's proving a bit difficult.

Remember here that my actual game will generally won't allow you to control above 100 ships (and only in the late game!). I want each ship to feel unique, and I feel this is one way to achieve that (helping them with damage taken, etc.)

Having ship systems overheat as combat proceeds feels gimmicky at best, but it does serve a function. I wonder if it could be rationalized in a different way? Perhaps treating energy as a short-term finite resource would help (aka, every shot depletes from the energy pool, and the energy pool only refreshes once per game turn).

I'll tinker with this possibility and see whether it affects other mechanics negatively.

Re: ship design, the reactor is not actually chosen by the player, it comes as a stock component aboard a specific hull. The player has little control over the entire energy output of each hull design (unless they "sacrifice" their special components slots to add extra energy instead of valuable sub-systems).

Making beam weapons less efficient is already part of the plan: since they don't consume ordnance and pool from infinite reserves of energy, they need to be less efficient. My means of achieving this currently is to have damage that scales up over time, the longer they hit the same target.

In this given approach, this makes them drastically less efficient than guns and cannons at short range (which deliver full damage from the first second) and hardly compete with longer ranged missiles which deliver more damage (but can be intercepted). They do serve a purpose however as they can effectively intercept missiles or focus fire on larger threats and eventually get to higher damage outputs.

But it's a strong weapon to deal with, as it can effectively wreck balancing plans.

Other weapon systems do use energy, but much less. In fact, it isn't about how much energy you have dedicated to your beam weapons, but how much idle power you can reroute to recharge or cool down your actual beam weapons. Beam weapons are nothing but focused directed energy after all. I anticipate that while cooling down, they would leave the ship in a pretty tight spot (all excess energy has been unleashed and the ship is recharging from the reactor). Any hit on shields at that point could be decisive, so perhaps that is one way of balancing this out (shields power oscillating with energy reserves and becoming extremely weak when beams are done firing and need to cooldown).

Food for thought.