Give the abilities to Buy/ Rent ship hulls/ blueprints, so that you can design and build ships based on those hulls/ blueprints, as well as retrofit ships you own that are based on those hulls/blueprints. 

You can tie this to the market place or diplomacy terms, where you permanently or temporarily get access to certain ship hulls in exchange for something. You may even sell or rent the ship blueprints of your faction/ you own at the market place, or give them to other players/ AI via diplomatic terms. 

Pirate ships at the market place are really bad, but they have standard slots, which make for decent ships if you can retrofit them. Maybe make it so that you can buy/ rent their blueprints at the market place so you can. 

Also, you can capture ships, with the DLC. The same applies to the captured ships if the AI didn't equip them well: potentially good and interesting addition to your fleet, but you can't retrofit them to be so.  

Player may have the option of choosing to sell the upgraded hulls or just the base hulls. You can hardcode to exclude certain hulls that may break the game if buildable by other factions (like Ark) from purchase all together. 

All in all, I think having more options with ships ad fleet compositions, and the potential to build ships of other factions are fun to have. 

I like it! Would be a cool addition.

why did you feel the need to post that

just thought it is random and silly, and fun to point out. 
Am I in trouble officer?

Yes

CaptainCobbs wrote:

Yes

My liege, I was but tempted! I'm sorry. Please forgive me. 

No

I just found out that re-skinned ships and original ships are considered different hulls. 
I play as a custom Vodyani faction with heretic re-skin, and captured some AI Vodyani ships. Their designs cannot be editted. 
Where as when I received a heretic Vodyani ship via the rescue mission quest, I can edit its design. 

All the more reasons to give more ship hulls access to players I think.