While the Bastion sounds promising, there was a fair amount of talk earlier that we should start working on a boarding craft, so I'd suggest switching the Bastion for the Narwhale boarding craft. Also maybe one of the better engine modules instead of an upgraded Warp Drive?
Our current engines are pretty decent though? We've already upgraded them, and they've got better stats then all the chaos merchant ships we've been fighting and are generally equal to the ork ships (one point better maneuvering, one point worse acceleration, and ours don't have the Volatile trait so don't randomly explode) while keeping the 'good fuel efficiency' ability of the base merchant engines, which I don't really want to loose right now because we're in the middle of a succession of sieges so operating efficiency is a good thing. Even for potentially sending some raiders out to, say, do some relief operations and support some of those forge worlds, I'm of the opinion that long distance operations can really benefit from fuel efficiency. But we've not upgraded our FTL engines at all, and we've been described as coming out of the warp all over the place and needing to reform the unit before we can do anything and the merchant FTL is outright called slow, so I'd prefer to upgrade our warp engines before going back to our normal engines.
The 'no need to double up on anti-boarding' point is a fair one though, I mostly just put them in because they were the life support and crew quarters upgrades that seemed most relevant out of what had been written up. There is the Oasis I guess...
I don't think we need both the Bastion housing and the AirGuard ventilation, or at least not on the same turn. We did pretty well over Uniary this turn, and they had a ton of dedicated boarding ships. I'd also like to see a shield upgrade; we really need that before we can do anything with the Bulk Hauler or other LC-sized vessels.
Point taken.
How's this look?
Potential Plan Airguard and Other Things
(Life Support) AirGuard Ventilation: What is, apart from expanded oxygen stores, a completely standard life support has been altered to provide a deadly last-ditch deterrent against boarding parties. If boarders have occupied a chamber, it can be isolated from the rest of the system, flooded with oxygen and have a spark introduced within. Gas baffles will disperse the explosive force without damaging internal bulkheads. It is also noted that the description of such serves as an excellent deterrent for crew mutinies.
(Boarding Craft) Narwhale Breacher Craft: The first dedicated boarding craft developed in the Crusade, the Narwhale outwardly bears a great deal of resemblance to the Harbinger Transport, because it uses the same hull configuration. Internal space has been sacrificed to add additional reinforcement to the superstructure, more powerful engines, and even install a small Void Shield. An array of hull cutters is affixed to the prow to force entry onto an enemy vessel and deliver its cargo of boarding parties.
(Warp drive) 'Longstride' Warp engine. While the typical drive utilized in merchant shipping suffices, the minimal use of technology and advanced components to save costs caused them to have slow charge times, greatly limited speed through the Warp and not being suited for fast/emergency jumps. The Longstride was Calavar's first attempt at improving their engines to something closer to what is utilized on Imperial Navy ships.
(Defence) Haptrix-Alpha Interlock Shields: The Haptrix-pattern shields are a serviceable design, but are fairly expensive, and have proven somewhat unreliable in practice. Perhaps worse, they are projected to scale up poorly both in terms of cost and in ability to stop capital-scale weaponry. This redesigned version uses a smaller number of larger shields to simplify the design and strengthen each pane, and arranges them in two concentric shells with the panes offset like bricks to provide redundant coverage.
Though if we do the boarding part, i want to really push people to either look at doing the Combat Servitor Bay soon, or another design that adds dedicated boarding troops to a ship. Something based off the army deck but for Naval Armsmen instead? (I'd use the word marines, but that might lead people to think I think we have access to the Astartes. Which we don't.)
(Utility) Combat Servitor Bay: While all ships carry armsmen aboard, they are primarily meant to combat human-scale opponents and lack the strength and melee prowess of some xenos and heretic forces. Supplementing onboard troops with monotask combat servitors outfitted with integrated chain-weapons and heavy firearms will give our troops means to contend with hostile invaders and supplement our boarding forces with readily available and obedient forces stationed across the ship. Their numbers can also be maintained by a built-in servitor processing facility where Adeptus Mechanicus adepts can recycle the gravely wounded into functional combat servitors.
Also if more people want a better normal engine instead of a better warp engine, here's the current write up suggestion for a better normal engine.
(Engine) Plasma Pulse Drive Array: One means of increasing the thrust of the merchant grade drives is to compress the expelled plasma and propel it through a narrower aperture in the drive nozzle. Such would even theoretically allow the new drives to retain much of the original's fuel efficiency, more so than simply making the drives bigger. The only complication to doing so is the increased thermal stress on the components, which made long burns infeasible without access to more advanced materials. Instead, the reduced size has been taken advantage of to include a greater amount of thrusters in the drive assembly, firing in short pulses in tandem to facilitate greater speed without risk of melting the drive. Because of the smaller size, each nozzle can now also be mounted on a gimbal, which allows for greater fine maneuvering mid-burn.
I'm not entirely happy about taking out the sensor upgrade, but it's not like we've been having sensor problems yet. Even if better sensors would probably help protect against the enemy raiders that are now showing up.