B483 and ISW223 has the rules for damage and effects.
Repairs Cost = dDmg*(Ship Value/dHPx6)*Ship Condition
Ship condition is the HT rolls of the ship, as it takes damage in B483 and ISW223
Functional - repairs are non-critical systems so the cost is about 20% or 1/5 the amount.
Disabled - Many critical systems were damaged. Cost of repair is 100% or 1/2 the amount.
Destroyed - All the ship's critical systems is down, cost of repairs is at 200% repair cost.
Lightning Class Frontier Merchant takes 20 dmg, the ship is ($250M/45*6) = $0.93M which is equal to $18.5M in repairs. Since the ship is in functional condition, it is assumed no critical systems were hit so it is mostly hull and armor damage. So the damage is now at $3.7M.
Example 2. A HT10 Terran Fighter ISW202 takes 20 dmg, damage is 0.183M. If the Fighter failed its HT roll after taking 20dmg and was disabled, but got back for repairs, the cost of repairs would be $3.66M
Example 2. A HT10 Hero Class Merchant ISW206 takes 60 dmg, damage is $0.377M per dHP. If the Hero failed its HT roll after taking 60dmg and was "destroyed", if a retrieval operation went underway it would cost (22.6*200%) $45.3M to repair her.
Note, It is possible for a ship to take dHPx3 dmg but have made all its HT rolls. the ship is disabled and the cost of repairs does not go up yet.
The Cheapest Solution
Rent a Berth, Source Parts (Salvage it when you can), and make the engineer earn his keep. Simple isn't it? In B474 materials are ~20% the cost of a product, parts can be a sourcing/trade roll like in Finding Goods for Sale ISW180. Of course its less time consuming if your ship has a:
- Techbots, a lot of Tech Bots.
- Heavy Exo-Skeleton 6-arms and designed to use harness to move around in 3d space on Gravity or M-drives to move around in 0G. Consider it a Fine Quality Heavy Exo Skeleton.
- Light Exo-Skeleton with 4 arms and designed to use
- Microboats with Mecha Arms that plug in to Hardpoints (x9 arms).
- Cargo Super Strong Netting - help haul stuff through space and has other miscelaneous uses.
- 1% of the ships value in equipment and supplies is minimal, ideal is up to 3%.
- The Cheapest Solution is also one of the Funnest Solution because its kinda DIY and a lot of Engineering and Merchant Rolls. In its own its actually an adventure.
Note: Finding Goods for Sale in the Real world is called Sourcing. I'm sure you can find out more if you use the key word sourcing.
Salvaging Rules is simply an extension of the repair rules. Usually when the ship takes dHPx3 worth of damage and it is destroyed, it now costs as much to buy one brand new (assumiing ship and market price is stable).
Basically the remaining Material Floating around is equal to the remaining dHP per cost to repair x 10% or 0.1 because its considered scrapped.
Retieval vs Scrapping - this is basically an Accounting distinction. To differentiate Salvage is for scrap while Retrieval is for repairs. They are two different ways of reporting a loss, it really depends on what favors which business how to report this.
Example 3A 10k Dton Freighter ISW217 with 120dHP has $3.4M per dHP. It was destroyed after taking 360dmg, repairing it would be more expensive than building a new one. The remaining derilict is now considered scrapped and is worth ($1,249M x 0.1) $124M as scrap.
There are some salvage rules in JTAS Cortez-Class Salvage Ship by Brandon Cope (you need to have a JTAS account to access). But basically Salvagers, the "State" (because they provide the berthing via Starport and adjudication), and of course the other parties involved each have their own commission.
Note it is a great use of Scrounging but what is more appropriate is Two stage roll Sensors + Per & Engineering/Mechanic + Per.
Note also that if you got the Microboats with arms or Heavy Exo-Sk maybe you can do some salvaging.
In light of how much repairs cost, there is a lot of risks in going into space - so charge it to your clients. Risk vs Reward is a factor in Market prices and again I emphasize "Market Rate" is arbitrary, when the GM all of a sudden throws a Pirate Infestation or WAR in the region Prices do not stay the same/static.
When there is criminal space activity, there are market forces that instigate Imperium to act on it. For one thing, what good is a technological and trade monopoly when you cannot squeeze profits out of an entire system. The funny thing about the Space Navy is that Nobles with Corporations Own the ships, and their revenues are what gets hit with Piracy.
Again my Ship Spreadsheet