So, what all is needed to maintain your voidship? I know if I look in the book, it'll tell me some of the bits, but lots of people have some variety of ship, and many don't have the resources of a Rogue Trader. Take the pirates, for instance. If you are not a Chaos Cult, turned to piracy, how do you keep your ship working? Do you still have AdMech to maintain the most complicated/arcane systems? Do you just park over a world you don't fear, and spend weeks slapping on new kibble and paint? I suppose most pirates don't have the best, and the biggest of craft, but they are somewhat more likely to be fired upon, and I'm not sure where they go for repairs. Are there pirate-stronghold shipyards out in the Expanse? I'd think some of the more pirate, less privateer examples might not even be able to enter port at Port Wander, or Footfall, without various people they once skirmished with just waiting for them to withdraw, and then blast them. I imagine that this is one reason most Rogue Traders are well-served by making friends, and keeping at least the worst of their character flaws in check, but what does it actually take to keep the ship in good shape? I imagine you could raid some worlds, and other small vessels, for food, water, some supplies, and the occasional crew restock, but how much can you avoid shipyards, the AdMech, and the authorities who want to kill you for piracy?

I see one option would be the good old "make a place up!" option, but they sometimes actively flesh this stuff out, so you can sometimes more readily see how it is associated with the other entities in the locale. Thanks much!

The Breaking Yard would be a good spot since they eject any party's who cause trouble in the system so a pirate could go their to get parts and supplies. But most likely they do most of the work themselves perhaps forcing captured Techpriests or hiring tech heretics

Well ,if your pirates did not turn to chaos there is a very good chance that your ad-mech contingent on board wont even notice and just keep doing their jobs.

RAW, Tech Use is the skill accessed for repair work. Multiple professions have access to this skill, and Voidmasters get complimentary skills even Explorators don't have access to sans Elite Advance. And then there's Hereteks....

Also, reclaimators are the lowest in the Adeptus Mechanicus hierarchy with skill significant enough to get them into trouble with the actual tech-priests.

Nabbed from the 40k wiki which sourced the DH Inquisitor's Handbook:p 76-77

"Reclaimators are the the most-skilled and certainly least trusted of the Adeptus Mechanicus ' minor ranks of Tech-priests . It is their task to redeem raw materials from old and damaged systems, to scavenge parts and be tasked with the endless cycle of minor repairs needed to keep a starship flying or a hive city ’s infrastructure from collapsing under its own weight. By necessity, a Reclaimator’s skills begin to stray into a higher understanding of machinery and technology than most of their brethren and many learn to worship the Machine God in a fragmentary and superstitious manner, marking them apart from their fellows. Reclaimators themselves are often sent into dangerous or unsafe areas with little direct supervision, and they scavenge and salvage a good deal more than their masters know. As a result, most Reclaimators have a well-deserved reputation as suspicious, shifty characters who sell their skills and the items they retrieve or repair for a good profit on the Imperial black market. Many have links to criminal gangs and more than a few are willing to resort to robbery and even murder to build up their spoils if they think they can get away with it."

I'm betting many ships, as well as non-Imperial shipyards, would have a large number of reclaimators to begin with and that they were used to operating beyond the dictates of the AD.

Also, the RT Battlefleet Koronus book states that Iconoclast class destroyers are far more often used by pirates and such who are not servants of the Ruinous Powers. The book then goes to state they are often built in shadow ports and orbital shipyards not affiliated with the AD, many of which are scattered in the Koronus Expanse. So, theser would be ideal spots for repair. Also, a bit of the history of the Calixis sector and Koronus Expanse dating back to the Angevin crusade shows that there was significant technology in the region prior to the Crusade- void ship as well as cybernetics.

Self-reliance and self-improvement are constant bedfellows. Just because the AdMech has monopolized technological production, maintenance, and development (as well as stagnated it), doesn't mean it is solely their purveyance. Though people aren't allowed to learn these things in the Imperium without being part of the AdMech, why does someone outside of both care for those laws, especially if they are wanted for breaking so many more? They learn these things as they go, or they fail to survive.

Into the Storm has a ship starting package, 'Reaver of the Unbeholden Reaches', which gives the vessel the 'self-reliant' rule. The description of it states that the reaver crews seldom have anywhere to take their ships for repairs, and pretty much have to do things themselves with whatever materials they have at hand. I can imagine a lot of jury-rigging and modification away from the holy templates when people are left to fend for themselves away from the AdMech, causing a lot of consternation between them on top of their other crimes.

Lastly, I wouldn't discount places like Footfall. Footfall is RIFE with crime and corruption. So long as they're not a crew of psycho reavers, or chaos marauders, I'm sure a pirate crew can get along just fine at Footfall so long as they promise to keep on their best behavior and have something to pay with. Same with the Breaking Yards. That these places possess groups willing to take their stolen goods certainly helps towards this end.