So its kind of a long term goal for my character to acquire a Ramilies-Class Star Fort and tow it into orbit around his chosen world. I know there was a write up of one a while back, but that was before BFK, so I was wondering if anyone had a better one.

I don't even think I've seen the first write-up of it, and certainly not one recently.

The Bulwark in Frozen Reaches is probably the closest approximation to a Ramilies in published canon.

A Ramiles class Star Fort? Well, that is quite a goal as each of them is a vital part of Imperial Fleet strategy, so getting one will be very hard indeed if not impossible. Realistically, I'd say that you should lead a Crusade to conquer the expanse for the Imperium of Man before they might even consider handing one over. In the old BFG game there were rules for requesting them. To have a chance, you needed enormous renown, or alternatively, you would need to trade in a forge world or hive world. As such, it is even beyond the league of battleships and feels to me quite a bit too grand for even the epic Rogue Trader game. But, of course, in your game you call the shots.

But, after procuring a Ramiles, there is the thorny problem of getting it into the expanse. The Imperial Navy has done it once, with the goal of supporting the full blown Crusade in the Jericho reach. Just a quick reminder, this was decided on no lesser level then that of the Lords of Terra themselves. After arrival at station 15 they determined that it was too dangerous to tow this craft through the portal and had to decide what to do with it. The voyage through the maw had been so hair raising, that the navy was loath to try and pull it back, as the chances were too high losing it. Thus, by default, it became Fleet Base Metis. Getting one into place over a planet in the expanse should thus involve a hair raising passage through the Maw, where even with the best Navigators there should be a serious risk of losing the base. Then, there is getting this ship deeper in the Koronus. While not as hard as the Maw, this is still a wild area, so makes the passage of this expedition a continuous risk. The longer the voyage would take, the higher the risk would be of still losing it.

Of course, there is not just the Ramiles. Most orbital stations are far smaller, but still are good space ports that offer good defence and repair facilities above a planet. The problem is that they seem to have to be constructed in place, so that is only an option above a well developed world. But nothing stops you from trying to get a pseudo-Ramiles and negotiate with the Adeptus Mechanicus and have a gellar field installed.

I myself would go for an easier solution and take a page from the Ork book (well, they are not the only ones, obviously): find a suitable asteroid near your planet, get it in orbit and build it out as you wish. A whole lot easier then negotiating with the Lords of Terra for a strategic piece of the first order and then having to tow it through one of the most hazardous parts of warp space.

Friedrich van Riebeeck, Navigator Primus, Heart of the Void

I've seen nothing official. Per request, I did write a totally unofficial version a while back, and I updated it once BFK came out. The updated version is reposted below, make of it what you will.

Cheers,

- V.

Quick stat and descriptive writeup of a Ramilies Class Star Fortress. The Ramilies is a vast and powerful space station, with extensive armaments and repair bays. Despite its colossal bulk, the Ramilies is designed to be moved over interstellar distances, though it takes a team of six battleship sized tugs and seventeen senior navigators to transport it through the warp. The Imperial navy uses them as mobile bases when a major crusade is in the offing, though a few have fallen into the wrong hands and support a Black Crusade of Chaos, or are used as pirate bases.

It goes without saying that an unclaimed Ramilies is a valuable prize indeed. An intact Ramilies class is too powerful for even a strong Rogue Trader vessel to defeat in a fair fight, though subterfuge or sabotage are certainly options; a GM who wants his players to think of creative solutions instead of relying on brute force could certainly make use of a Ramilies in his campaign. Of course, a Ramilies might well be damaged, and getting it repaired could well be an adventure in itself.

Tabernacle of Lord Angevin
Class: Ramilies Class Star Fortress
Speed: 0 [1 under tow]
Maneuverability: N/A [-40 under tow]
Void Shields: 4
Detection: +30
Armor: 24
Hull Integrity: 400
Turret rating: 4

Equipment: Ramilies Hyper Plasma Reactor[*1], Ramilies Warp Bubble Generator[*2], Gellar Field, Quad Void Shield Array, Command Bridge, Hydroponics Decks[*3], Voidsmen Crew Quarters, Command Station Auger Array[*4], Small craft repair deck, Repair Docks[*5], Munitorium, Servitor Reclamation Facility, Civitas Decks[*6], Medicae Deck, Barracks, Temple-Shrine to the God-Emperor, Librarium, Murder-Servitors, Observation Dome, Teleportarium, Astropathic Choir-Chambers, Cogitator Interlink
Machine Spirit Oddities: Martial Hubris
Past History: Haunted
Maximum Morale: 94 (losses 1/4 normal, +1)
Max Population: 105 (losses 1/4 normal, -3)
Crew Quality: Competent (Skill 30)

Weapons, Each quadrant arc (4):
Sunsear Las-broadside - Macrobattery; str 6; Dmg 1d10+3; Crit 4; Range 9
Hecutor Plasma broadside - Macrobattery; str 5; Dmg 1d10+3; Crit 4; Range 11
Godsbane Lance Battery (x2) - Lance; str 2; Dmg 1d10+2; Crit 3; Range 12
Jovian pattern Landing Bay (x2)

Weapons, Basilica (keel):
Ryza Plasma cannon battery (x2) - Macrobattery; str 4; Dmg 1d10+5; Crit 4; Range 5
Mars pattern torpedo tubes (x2) - Torpedoes; str 6 each [*7]

Special Rules:
Four equal quadrants - Due to the Ramilies' huge size and symmetric construction, all four arcs, port, starboard, prow, and aft, use the rules for side arcs. In other words, the Ramilies has four equal sides; weapons in each can only fire into their own 90 degree arc, but all four sides can, and do, mount broadside weapons.

Big as a Hive Spire - Due to the Ramilies vast bulk and huge population, morale losses from damage are only 1/4 normal, rounded down, before applying any modifiers for equipment. Also, it may mount systems for any size ship, but must always mount the largest if there is a choice.

Space station - Unless it is under tow, the Ramilies Class does not move or turn in combat, and cannot be moved by an outside force. The station's massive banks of position keeping thrusters and grav stabilisers ensure that it will stay in a stable orbit.

Stable firing platform - The huge bulk and massive inertial dampers provide a superb platform for accurate, long range fire. The Ramilies has a +10 bonus to all ballistic skill tests with macrobattery and lance weapons.

* Special Systems:
1 - Ramilies Hyper Plasma Reactor. This immense generatorium uses principles poorly understood by the Mechanicus. It provides more than enough power for all the fort's systems. Unfortunately, if it ever goes critical, the resulting explosion will be colossal. If the Ramilies ever suffers a plasma drive explosion, apply the following changes: The test to avoid damage is Arduous (-40), the blast radius is 1d10 + 10 VU's, and the damage is 2d10 macrobattery hits.
2 - Ramilies Warp Bubble Generator. This arcane device allows the Ramilies to be towed through the warp. Unfortunately, it requires vast quantities of bottled warp energy to function, with horrific effects if the device is ever destroyed. If the Ramilies ever suffers a Warp Drive Explosion, double the radius and damage of all effects.
3 - Hydroponics Decks. These provide fresh air, clean water, and food, even if it is only algae paste. The Ramilies suffers no penalties to crew population or morale no matter how long it stays in the void.
4 - Command Station Auger Array. The Auger Arrays on the Ramilies are not only high quality, they are far larger than anything a ship could mount. They provide a +20 bonus to detection (already included) and score one extra degree of success on a successful roll.
5 - Repair Docks. The Ramilies can completely repair docked ships or itself with enough time and effort. A Ramilies has four docking spines. Each of these allows a vessel of Grand cruiser size or smaller to dock. Additionally, a Ramilies can dock twelve frigate or smaller size vessels internally. Each docking spine is a huge version of a manufactorum. Internally docked ships (and the Ramilies itself) receive a +10 bonus to Tech-Use tests for all repairs as the internal docks have air and gravity, allowing the laborers to work in shirtsleeves. These can also be used to build frigates or smaller vessels given enough time and resources.
6 - Civitas Decks. The Ramilies is, in effect, a small city in space. The Civitas Decks can comfortably house a half million or so civilians, with all the amenities you'd expect in a modest city.
7 - The Ramilies' command basilica has a cluster of anti-ship torpedo tubes. These have triple the normal torpedo stores due to the vast size of the station.

Relevant Modifiers:
+20 to Ballistic tests with ship's weapons from bridge (still +15 if Bridge is disabled)
+5 to all Command from bridge
+20 to Hit and Run tests.
+10 to Tech Use tests for repairs on itself or escort sized ships.

Bonuses from equipment are already included in the above statistics.

History:
The Ramilies Class Star Fortress named "Tabernacle of Lord Angevin" was recovered and reconsecrated by Imperial forces just in time for service in the Angevin Crusade. (Its history prior to the Crusade has been sealed by a high level Inquisitorial writ, but it is believed to have been transferred from the Mandragora sector in late M37.) The Mechanicus lavished much attention on the refurbished fortress, declaring it sacred and equipped it with the best manufactoria plus an exceptionally high proportion of servitors. Though it was never on the front lines, the Ramilies orbited Solomon for much of the Angevin Crusade, providing a vital link in supply lines and critical repairs to the Imperial Navy. It was never a popular post during the Angevin's Crusade, with officers preferring the chances of glory in a ship command, and the enlisted crew constantly muttering that the fort was cursed. The Tabernacle saw two significant Xenos raids during the fighting, as well as one major sabotage attempt, but the fort survived.
In the millennia since, the fort has served Battlefleet Calixis well, being moved from Solomon to Malfi in 891.M39. It remained around Malfi, supporting naval operations in the Malfian Sub until 772.M41. In that year, it was reassigned and sent into the Koronus expanse to support the increasingly troubled Margin crusade. (This was done by order of Lord Sector Marius Hax, over the vocal protests of many Malfian nobles, an act which further soured political relations between Malfi and Scintilla.)
In 788.M41, the Imperium lost contact with the forces of the Margin Crusade. The Tabernacle of Lord Angevin was but one of many losses suffered by the Imperium in that ill fated venture. The surviving Imperial records do not show where the fortress was located in the Koronus expanse, or even if it arrived.
Today, the Tabernacle of Lord Angevin drifts in the Koronus Expanse. The crew are all long dead, though the fortress is still blasphemously active... The station is haunted or controlled by some unknown entity. Perhaps it is the ghosts of former crew from the Margin or Angevin crusades. Perhaps it is some warp entity or insubstantial xenos (Cryptos?) that possesses systems and motivates them to function. Or perhaps the Cogitator Interlink is, in fact, an AI. Whatever the cause, systems still function, and servitors walk the halls, mindlessly carrying out their allotted tasks. From a distance, the station appears mostly powered down, though a few eldritch lights still shine in the windows. However, a successful active augury reveals void shields and weapons are active, and the fort will fire on any ship that gets close. (Broadcasting the correct Imperial Navy access codes might allow a ship to dock, though these should be very hard to get... and this only works if the controlling entity is the AI. Warpspawn or Cryptos will feign compliance, and then Lock-On with all available weapons at point blank range.) The safest way to board is probably to take a small shuttle on silent running and sneak in. The interior has moderate damage; some areas of old damage have not been repaired, and the fort suffered considerable fighting when the possessing entity took control and exterminated the remaining humans. There are many, many active servitors on board, some of them blasphemously corrupted or heretek designs, and these will oppose any attempt at recovery. A brute force solution will be very expensive. The elegant solution is to find and eliminate whatever entity is possessing the station... Once it is defeated or placated, then the fortress can be salvaged without resistance.
Naturally, the Tabernacle of Lord Angevin contains a vast amount of Imperial military hardware. It is unlikely to have very rare items, but it has squadrons of small craft, plus enough tanks, transports, weapons, and other materiel to equip several regiments. Returning it to Imperial control would earn a big reward for the explorer's dynasty, and attract the attention of several prominent noble houses on Malfi.

Why do they want a giant, 'Kick Me!' sign attacked to their backs?

Its not as if I planned on towing this thing with me everywhere. It will probably end up sitting above a world somewhere (probably a resource rich one important to my dynasty) and guarding it and acting as a base for my fleet. In all likelihood, its acquisition will probably mark my character's retirement as well.

It also helps that my character has contacts within the Mechanicus, Administratum, and Inquisition. Furthermore, my dynasty was founded (a long time ago, mind you) with the purpose of reclaiming STC fragments. Recovering one of those would definitely help my chances. But I think I could settle for a huge space station too.

Sounds like a great adventure. But instead of towing this thing to a unclaimed world to claim it? Why not tow it someplace to like Lucien's Breath? This way ships from Lady Chorda or Lord Winterscale could stop and repair before heading back to sell their wares. Or help tip the balance in who controls the world below...

Mainly because my GM doesn't run our group in the Expanse, but in a homebrew sector.

That would be a great idea however....