The way I was figuring is that the geo and grav ships use commercial engines for fuel economy but are classed as military with military jump engines which  I think cost more to build.  In my limited experience I have needed more military slips anyway to build and maintain my military fleet and in a pinch my survey ships have acted as jump ships for small military fleets without needing a dedicated military jump cruiser until the military fleet has needed a dedicated support vessel. 

This doctrine may be well off the mark in efficiency, but in my current game my auto generated SY was 3 navel yards and 1 comm yard so this doctrine fit RP wise.  It was also made possible via starting RP and further assisted by having no propulsion researchers.  So I started with military jump drives but lack an efficient researcher to develop a commercial drive so never committed the research facilities to it.

The M/C difference was irritating between them, I just add a random sensor to make the geo ship military so i can use the same jump drive.  Or am I missing a toggle switch where I can specify a design as military without adding military parts to it?

I think I've had the AI do some stupid rammings, like trying to ram a ship twice its size and exploding while doing no damage to my ship.

A ramming would be rather fun.   I armored up that Geo ship for nebulea survey work.   He was a bit tougher then his size and mission would have implied.   Do ship explosions have an area effect?  If my ship was rammed would the attacking ship be damaged not from the impact but from the systems explosions, such as engines or magazines?  I think someone mentioned a collier or missile cruiser or something being rammed and the rammer died, but it was non-specific on if the impact damage or resulting magazine explosion is what killed it.

On a completely off-topic thought:  Why are unarmored grav ships military vessels and the same identical (copied) config modified with geo sensors classed as commercial ships?

Thermal signature is only produced by engines, right? I don't know how the signature works with the engine, but they might have a smaller engine that is higher tech than yours and a bigger ship. The only way to know how big it was is by painting it with active sensors until your intelligence officers give you a size.

I think I've had the AI do some stupid rammings, like trying to ram a ship twice its size and exploding while doing no damage to my ship.

Maybe, who knows why xenos do what xenos do?  They're about as predictable as khornate cultists, and generally run screaming into your missiles with just about as much tactical sense.  

When I have ships without sensors, I note strange behavior.  The alien approaches, though it could fire missiles from far away, as if to give the crew a chance to look out the window to see the ship-- and thats what happens.  Then, generally, my ship dies.  In this case it did not.  Weird!

Crazy xenos.

Purge em with nuclear fire. (its the only way to be sure)

They might simply not be able to shoot you.   As in out of missiles.   Usually they have missiles in system that they can go reload from, but maybe they're weaponless troopships or something.

In this instance what you say may well have been the situation.   My ship was slow and the first contacts may have been unarmed or ammo depleted.  In the intervening time frame equipped warships were able to reach missile range.


Thank you for the relations score info.

As far as the numbers go,

199 to -100 is Neutral
200 is Trade allowed
800 is Friendly & Geo-survey info can be traded
2400 Gravsurvey sharing allowed
4000 Allied Status allowed
6000 Research can be shared

As far as the negatives go, generally once you go hostile, its pretty much war from then on.

Things like painting their ships with actives sensors, having military ships in their systems, all contribute to a negative gain every month. Thats offset by having Diplomatic teams working on improving the relationship.

I think if communications are impossible, they are precursors.