Is there a way to disable automatic ship designs?

Mod a custom faction and erase all blueprints in their FactionShipStyleSetDefs.xml (or mod the file completely with the original factions)

Just keep these things: (faction specific obviously)

<ShipClass>YorStartingScout</ShipClass>
<ShipClass>YorStartingSurvey</ShipClass>
<ShipClass>YorStartingColony</ShipClass>
<ShipClass>YorDroneInterceptor</ShipClass>
<ShipClass>YorGuardianFighter</ShipClass>
<ShipClass>YorAssaultFighter</ShipClass>
<ShipClass>AwardYorScout</ShipClass>
<ShipClass>AwardYorCutter</ShipClass>
<ShipClass>AwardYorDefender</ShipClass>
<ShipClass>AwardYorGunboat</ShipClass>
<ShipClass>AwardYorSurvey</ShipClass>
<ShipClass>AwardYorFrigate</ShipClass>
<ShipClass>AwardYorOverlord</ShipClass>
<ShipClass>AwardYorColony</ShipClass>
<ShipClass>AwardYorConstructor</ShipClass>
<ShipClass>AwardYorFreighter</ShipClass>
<ShipClass>AwardYorTransport</ShipClass>

It's not easy, but it was great once it worked

I'm pretty sure that could mess with the AI's ability to produce default ship designs.

I think a safer method is to open ShipClassDefs and for the chosen race, insert or modify the line "isAIonly" from "false" to true.

No?

That is why I did it on a custom faction I modded myself and not the original ones. (the AI is not allowed to touch that one ) However your solution is probably friendlier for the AI in the long run if it works. 

Yeah, my method seems to work well, my mod (Gauntlet's Race Mod) utilizes this method on 9 ship sets. AI still has access to all its crummy default designs, whilst my list is clean.

I am confused.  If i  obsolete a ship, any ship it stays obsolete any you never see it again in that game even after  I research a new technology.   Yes it is a lot of ships to obsolete but it keep my list V short

That has not been my experience. Each new relevant tech triggers a "respawn" of the undesired design.

G, V V Strange.   Just went back in and tested it to make sure i was not dreaming.   In designer i select a ship > obsolete it.  Researched next engine, life S, & weapon.   Ship did not "respawn" 

Isn't the easiest way to simply just use the tab "user" and forget the "core" and "all" tabs?

I'd like to see an option to turn off the auto ship designer.  I never, ever build a game designed ship, but when I go to upgrade a ship in the field, I have to scroll past those annoying designs.  Maybe I'm missing it, but I only see and "ALL" tab when I upgrade.  I'll look harder next time.

I obsolete the designs, but new ones keep popping up.  It's not the same as the previously obsoleted design, but a new one that takes its place.

It's a small thing, but annoying nevertheless.

...or just mod them to make the default designs work the way you would make them, and save yourself hundreds of hours of busywork in the ship designer.

I am still really confused here, or really dumb and missing what ya'all are saying.  I have played dozens of games.  If i obsolete say the default ai colony ship and research new engines / sensors/ life support, the AI colony ship NEVER comes back.  Same with any other default ship.  Now the first time i research a new hull; e.g. med/lrg/huge;  all the new hulls do show up, but i obsolete them and never see them again.  So do i just have a lucky bug on 2 different machines, or am i misinterpreting "new ones keep popping up"?

Maybe not a colony ship, but something of that size will infiltrate the upgrade box when a new tech is researched. I can always tell because it's name will be something "cute".  Granted, there aren't many cargo class ships, but there are plenty of small, med and large ones.

But i have done on ALL types & classes of ships, cargo, transports, tiny/sml/med/lrg/huge war ships.   Everyone i don't want (which is most) i obsolete and I NEVER see them again, no matter how many tech upgrades i research. 

So, they don't come back the next game?

Perhaps it's because I've been playing different races per game.  I'm almost done with all of them, so it won't be long.  Thanks for the heads-up.

OOOOoooH  said the blind men to the deaf person. .  Yes they always come back at the START of the next game.   Is that what you were referring to?  The way i read it was Default ships were repopulating the shipyard list each time a new tech leveled the up ie scout M1 to scout M2.  If i obsolete the M1 i never see the M2 for the rest of that game

I was actually so frustrated by the clutter and constantly clicking the 'Obsolete' button that I made a mod that disables the default ship designs for all the vanilla races, the AI still use them obviously. http://www.nexusmods.com/galacticcivilizations3/mods/39/?