Aurora C# Propulsion Design Theory

[Pedroig]

This might be veering a tad off topic, apologies in advance if so.

In general, a "balanced" warship would devote about 30% of its mass to defense, offense, and power, with the remaining 10% for sensors, accommodations, etc.  Each of those categories can have a fairly "loose" definition, defense can be armour, shield, PD, AMM, and Stealth for example.  Likewise making "specialists" like Battlecruisers (Pocket Battleships) with Battleship guns with Cruiser defense, or Sensor/Scout ships like an AWACS aircraft can be done as well.

Now since in the game, accommodation is more or less a set "ratio" of mass taken, it can really bite into the 10%, unless it doesn't as one can count it in the other category as well.  Which leads to the interesting quandary that speed can be a type of defense as well, both in regard to a base hit chance as well as the ability for one's PD to be more effective.  So making a "Fast BB, CA, CV, or even DD" can be done by combining the power and defense aspects without much effect on the overall offensive output.

On the tanker issue, the problem is that realistically one would be required to support/guard the logistical supply line, else a smart enemy would simply sever the chain, and play an attrition game.  So by increasing operational range by the use of tankers, one reduces the offensive weight of any action, since some portion must be used to escort the tankers.  Only if one has reasonable "space superiority" can one "risk" not escorting them.  (static defense JP's which are not stabilized for example)

Overall, I find myself using even engines on civilian commercial vehicles, and odd engines on military, with only Fighters having a single engine, the loss of optimal output is outweighed by the redundancy of reliability, same thing goes for reactors, RP-wise I find having a port and starboard or fore and aft reactior, each being able to handle the load of the entire ship, "right" for a warship.

In closing, thanks to nuclearslurpee for putting on a maths treatise.  Could have jumped to the final answer of 42 though... 

[nuclearslurpee (OP)]

In general, a "balanced" warship would devote about 30% of its mass to defense, offense, and power, with the remaining 10% for sensors, accommodations, etc.

I would push back on this bit. 30% dedicated to propulsion is much too low in most cases, unless you are using highly boosted engines in which case your expenditure in fuel and logistics will be proportionally greater. From general experience* I would say that anywhere from 30% to 40%, roughly, should be dedicated to engines, and once you add fuel load you may be pushing close to half of your tonnage dedicated to propulsion. For weapons I consider 20% a minimum, but if I can get 30% that ship is usually slow or a glass cannon. Defenses, 30% is far too much even if you are counting a nominal PD capability on every ship. Outside of very low-tech or specialist designs I wouldn't want more than 10% armor by mass, and similar for PD unless it is of course a dedicated escort class.

*NPR warship designs use between 30% to 42% engines, and this is a good benchmark for player-designed ships as well.

More generally, I don't think it makes a lot of sense to prescribe rigorously the percentages involved. Warship design should be determined by the balance of strategic, operational, and tactical concerns of the race first and foremost - hence why, while the 3:1 ratio is an important theoretical limit, in practice one should incorporate fuel loading into the design specification.

[Jorgen_CAB]

The most "balanced" multi-purpose ships are about 35-45% (Propulsion, Fuel), 25-30% Weapons, 15-25% Defence (Armour, Shields, AMM, PD etc...), 15-20% (Sensors, Hangars, Command etc...). That is also only about 80% of the ship of the ship as you also need crew, maintenance and supplies too.

If you only spend less than 30% on missions tonnage because more than 50% is engines and fuel I think the design generally is not well constructed. I would only consider that if speed is extremely important. 50% mass to engine and fuel will be more like 70+% when you add all the crew, maintenance and armour you need as well. The only ships I have in my fleets with 40% engine mass are huge carriers with commercial engines, but that is more of a special case for me.

For the most part... I consider overall fuel use less important than manage to fit as much mission tonnage in the ships... I need after all maintenance facilities for them as well. This is why I often look at the fuel efficiency of engine design as one of the important metric.