Splitting off from the Jump Gate thread.
A fourth option for balance would be that construction ships (or whatever they're to be called) would require more resources to build something than a shipyard would. That way you pay for your flexibility in mobility and not needing to retool with a resource surtax.
That's a possibility, though I personally don't like it.
How about just don't allow construction ships to build engines? That way they can't build ships, and you'll still need shipyards.
Yeah, that definitely seems like an option, assuming it's not difficult to program. The main thing for me is that I'd like to have construction ships that can build stations, and the reason for that is the lack of mobility. Stations definitely look like they'll be more important, but if you have to rely on tugs to get them anywhere other than a colony with a large shipyard, I feel like that will limit their usefulness. If you can build them on site, however, that's a different story. At the same time, ships that can actually move around don't really need this, so preventing construction ships from building ships seems like it would prevent a lot of any potential abuse construction ships might otherwise allow.
Perhaps construction ships could be handled like combat engineers assembling PDCs? The components for the construction would need to be built planet-side, and a construction ship could only assemble them in space?
That also definitely seems like a good limitation. Should definitely help to cut down on the versatility of construction ships. I guess you could still manufacture a bunch of parts for different things to try and maintain that versatility, but that would require a significant amount of minerals, so I think it should be fine.
Conversely(or additionally), perhaps construction ships should need to be tooled at shipyards for specific projects? And that the project they're tooled for has to be done at a shipyard that could have done the construction itself(that way you can't have a 500 ton shipyard tool a construction ship for a 100k ton project). It makes them more of an extension of a shipyard in that sense: a mobile slipway with the same costs and limits associated with the shipyard, but the advantage of being able to lay down construction at a specific location.
I feel like requiring premade components serves more or less the same purpose, and in a more elegant way (though of course that's just my opinion).
Though maybe with a construction speed penalty added, to represent a lack of easy access to experts and specialized equipment if(when) problems during construction come up? That way there's at least some incentive to still use shipyards most of the time, and make construction ships only appealing for projects that simply can't be done at a colony.
Well, if construction ships can only build stations, you'll definitely still be using shipyards to make your actual ships. I do like the idea that shipyards do have an advantage in building stations if you are willing to actually make a shipyard big enough to do so, so a bit of a speed reduction on construction ships might be a good idea. Of course,