2300 Rocinante project

[tytalan]

So I’m working on making the Rocinante from the Expanse in 2300. It’s going to be a shutterwarp ship but my goal is a reasonable version of the ship. In the series it’s classified as a Frigate which i think would work well. So here’s my starting point
TL 12 military
Hull 300 dt, composite space frame: Armor 12 pt (-18 dt), Advance, Radiation Shielded, Stealth.
Here’s the first question drive I’m thinking a Advance Nuclear OMS drive what’s everyone thoughts on this

 

[boggo2300]

I thought it was an MCRN Corvette

 

[Condottiere]

The Corvette-class light frigate[1] is a class operated by the Martian Congressional Republic Navy (MCRN).

The most widely known ship of this class was originally called the MCRN Tachi and was carried in the main hangar bay of the MCRN Donnager. Later, after surviving the attack on the Donnager, this same ship was renamed Rocinante by her new captain, James Holden.


I admit I'm also guilty of deliberately screwing with, and double entendreing, class names.

 

[boggo2300]

The Corvette-class light frigate[1] is a class operated by the Martian Congressional Republic Navy (MCRN).

The most widely known ship of this class was originally called the MCRN Tachi and was carried in the main hangar bay of the MCRN Donnager. Later, after surviving the attack on the Donnager, this same ship was renamed Rocinante by her new captain, James Holden.


I admit I'm also guilty of deliberately screwing with, and double entendreing, class names.

if thats the case, I'll yell at James on Bluesky

 

[Condottiere]

Normally, you wouldn't want a dreadnought to sink.

 

[boggo2300]

Normally, you wouldn't want a dreadnought to sink.

submerge<> sink

Submarines also sink, usually with very few to no survivors....

 

[Takei]

So I’m working on making the Rocinante from the Expanse in 2300. It’s going to be a shutterwarp ship but my goal is a reasonable version of the ship. In the series it’s classified as a Frigate which i think would work well. So here’s my starting point
TL 12 military
Hull 300 dt, composite space frame: Armor 12 pt (-18 dt), Advance, Radiation Shielded, Stealth.
Here’s the first question drive I’m thinking a Advance Nuclear OMS drive what’s everyone thoughts on this

My back of a fag packet calculation put it closer to 400 dT.
A quick Google shows the Roci to be about 46m long and from various pictures seems to be about four times longer than it is wide:
11,5 x 11,5 x 46 =6 083,5m3 / 14 =434,536 m³
The grognard in me likes 400 dT as it's the classic SDB size, which also seems to be close to MCRN Tachi's role

 

[tytalan]

My back of a fag packet calculation put it closer to 400 dT.
A quick Google shows the Roci to be about 46m long and from various pictures seems to be about four times longer than it is wide:
11,5 x 11,5 x 46 =6 083,5m3 / 14 =434,536 m³
The grognard in me likes 400 dT as it's the classic SDB size, which also seems to be close to MCRN Tachi's role

It’s also only supposed to have a crew of 20 including its 6 marines. Also it’s only a SDB because in the series they don’t have a real FTL and I definitely am expecting this one to have more than just system legs. Though I do agree that 400 dt might be a viable option I also want to keep the crew down to the 20 if possible.

 

[Bryn the 2300AD guy]

A post of mine from the facebook group from 2021:

I got to watch the latest season of The Expanse the other day, because the previous occupant of our holiday flat didn't log out of Amazon. It got me thinking, in 2300AD terms what sort of ship is the Roccinate?

Scaling of Expanse ships matches 2k3 pretty well, with PDC numbers being in the same range as 2k3 turrets. Expanse battleships have 40-60 PDC's (the Donnager class having the most at 59), whilst torpedo boats and patrol ships have 2. The Roccinate has 6 PDC's, which would equate to 6 lasers.

The number of torpedoes on Expanse ships is a little nebulous. The Roccinate has magazine space for 20, and can fire a pair at once from a side mounted single launcher, of whch she has two (4 torps per max. salvo on screen). The "heavy frigate" has 40. When Donnager took on the stealth ships, she launched 20 torpedoes at them from her 6 very large launchers. The stealth ships fired 2 torpedoes each in every encounter.

The converted belter ships fired many more torpedoes, but it should be noted they weren't Epstein drive torpedoes (cf the yellow rather than blue [exhausts]) and so have far less capability. In the attack on the Ring gate you can see the CL Pella fire ca. 12 blue drive torpedoes, and other ships firing salvoes of yellow drive torpedoes (4, 9, 8, 10, 10 and 8 onscreen) within railgun range. These > 61 torps (since some salvoes aren't seen) were defeated by the BB PDC's. Medina station fired 6 blue drive torpedoes into the Martian BB, killing her. The Laconian torps are difficult to separate, but it looks like the Barkeith (a Donnager) fired 10 blue drive torps at each of the remaining BB's.

In the Zmeya fight, the Zmeya has 24 torpedoes in her forward bay (in six quad packs), and fires 23 yellow drive missiles at the Roccinate, and a blue drive "stealth torpedo" with the protomolecule away from the fight. Drummers ships had 8 torps (Tynan), 17 torps (DeWalt) and an unknown no. (Mowteng, 23 can be counted on the hull of the concept art and she likely had ca. 30-35). All simply strapped torpedoes outside of the hull.

Missiles thus seem to be more common in the Expanse than 2k3.

The other weapons system, railguns, could perhaps be represented by the large lasers the Kafers and a few Terran ships (Piedrabuena) have. This would be especially true if you use house rules that allow large arrays to focus further.

Anyway with 6 laser turrets, and a pair of missile launchers fed by a significant magazine, the Roccinate is roughly equivalent to a Kiev type destroyer in 2k3. No wonder it was missed.

 

[Condottiere]

In theory, you could supplement armament with groundscale weapon systems.

 

[tytalan]

A post of mine from the facebook group from 2021:

I got to watch the latest season of The Expanse the other day, because the previous occupant of our holiday flat didn't log out of Amazon. It got me thinking, in 2300AD terms what sort of ship is the Roccinate?

Scaling of Expanse ships matches 2k3 pretty well, with PDC numbers being in the same range as 2k3 turrets. Expanse battleships have 40-60 PDC's (the Donnager class having the most at 59), whilst torpedo boats and patrol ships have 2. The Roccinate has 6 PDC's, which would equate to 6 lasers.

The number of torpedoes on Expanse ships is a little nebulous. The Roccinate has magazine space for 20, and can fire a pair at once from a side mounted single launcher, of whch she has two (4 torps per max. salvo on screen). The "heavy frigate" has 40. When Donnager took on the stealth ships, she launched 20 torpedoes at them from her 6 very large launchers. The stealth ships fired 2 torpedoes each in every encounter.

The converted belter ships fired many more torpedoes, but it should be noted they weren't Epstein drive torpedoes (cf the yellow rather than blue [exhausts]) and so have far less capability. In the attack on the Ring gate you can see the CL Pella fire ca. 12 blue drive torpedoes, and other ships firing salvoes of yellow drive torpedoes (4, 9, 8, 10, 10 and 8 onscreen) within railgun range. These > 61 torps (since some salvoes aren't seen) were defeated by the BB PDC's. Medina station fired 6 blue drive torpedoes into the Martian BB, killing her. The Laconian torps are difficult to separate, but it looks like the Barkeith (a Donnager) fired 10 blue drive torps at each of the remaining BB's.

In the Zmeya fight, the Zmeya has 24 torpedoes in her forward bay (in six quad packs), and fires 23 yellow drive missiles at the Roccinate, and a blue drive "stealth torpedo" with the protomolecule away from the fight. Drummers ships had 8 torps (Tynan), 17 torps (DeWalt) and an unknown no. (Mowteng, 23 can be counted on the hull of the concept art and she likely had ca. 30-35). All simply strapped torpedoes outside of the hull.

Missiles thus seem to be more common in the Expanse than 2k3.

The other weapons system, railguns, could perhaps be represented by the large lasers the Kafers and a few Terran ships (Piedrabuena) have. This would be especially true if you use house rules that allow large arrays to focus further.

Anyway with 6 laser turrets, and a pair of missile launchers fed by a significant magazine, the Roccinate is roughly equivalent to a Kiev type destroyer in 2k3. No wonder it was missed.

While I understand where your coming from a Destroyer is way too large and is more likely to have a crew of 40+ not the 20 that the Rocinante is supposed to have also its six guns are point defense not attack weapons. Now I know it’s got 6 turrets in the show but it’s also been pointed out in the show that only about half can fire in any one direction so I believe that 3 ODC Type 29 can easily represent those 6 guns (if I remember right though a PDD does require a HardPoint it does not require a Turret). As for torpedoes that’s the same thing as drones which are commonly used in 2300, I think 2 40 ton drone bays will cover this (most attack drones are 4 or less tones) and a 20 ton drone bay for their other drones. Probably have to go with takei suggestion and go 400 dt. I can still probably get the crew down to 20 with this but there’s no way a 700dt ship is going to have a 14 person crew and 6 marines.

 

[Condottiere]

Twenty tonnes of point defence represent multiple turrets.

 

[tytalan]

Twenty tonnes of point defence represent multiple turrets.

??? What are you talking about a PDC Type 29 is 2 dt 3 would be 6 dt, point defense only needs a hard point not a turret. Please explain

 

[Condottiere]

A point-defence laser battery consists of linked short-ranged laser turrets controlled by their own automated computer.

...

Point-defence gauss batteries are also available but primarily serve as a defence against torpedo attacks.

 

[tytalan]

A point-defence laser battery consists of linked short-ranged laser turrets controlled by their own automated computer.

...

Point-defence gauss batteries are also available but primarily serve as a defence against torpedo attacks.

I don’t see either in the Aerospace Engineering Handbook. I think your looking at High guard which is not used in 2300

 

[Condottiere]

High Guard being the basis of Traveller associated or adjacent settings for spacecraft design.

Personally, I don't particularly agree with how point defence batteries rules are set up, but it does explain multiple turrets, on a limited hardpoint budget.

 

[MasterGwydion]

High Guard being the basis of Traveller associated or adjacent settings for spacecraft design.

Personally, I don't particularly agree with how point defence batteries rules are set up, but it does explain multiple turrets, on a limited hardpoint budget.

2300 has its own version of High Guard. That replaces the regular High Guard.

 

[tytalan]

High Guard being the basis of Traveller associated or adjacent settings for spacecraft design.

Personally, I don't particularly agree with how point defence batteries rules are set up, but it does explain multiple turrets, on a limited hardpoint budget.

I suspect you don’t have a copy of the Aerospace Engineering Handbook if you did you would know that it completely replaces HighGuard for 2300 and HighGuard is not the basis for spacecraft rules for the 2300 setting. You can’t use anything from HighGuard in 2300 it even has its own space combat rules. No system is the same and weaponry is completely different, for example both turrets and barbettes only have one weapon each (no double, triple or quadruple turrets). There are no sandcaster, fusion, there are lasers and particle weapons.

 

[Sigtrygg]

AEH page 67

"Point defence weapons are clusters of fast-cycling lasers intended to engage drones and fighters at close range"

For a 400t version that gets you 4 hardponts - pd, 2x launcher, (railgun)

 

[Bryn the 2300AD guy]

Rocinate has a volume of about 750 dTons +/- 50. In Traveller terms she'd be an 800 dTon ship due to the 8 hardpoints. In the Expanse universe a frigate is simply a warship without a railgun, vs a destroyer (spinal mount railgun), cruiser (single turreted railgun) or battleship (2 turreted railguns). PDC's are abolutely an offensive weapon - see the spin station battle or Rocinate vs Pella.

The entire idea of "point defence" is 2300 is silly. The missile weapons used do not impact the target, but fire blasts of X and gamma radiation from a significant distance away, although less than you'd think. Bomb-pumped nuclear "lasers" are not focused but instead are collimated. They are reasonably narrow at 100 km or so, but quite broad at 1,000 km. Any anti-missile defense has to hit the missile whilst still warping towards the target. Remember, warp 1 is 1,200 km/s. An attacking missile is only within 1,000 km for a fraction of a second before detonating. Compare with a modern sea-skimming missile which can be engaged effectively for at least 10 seconds by CIWS.

The Mongoose 2k3 laser is a different beast to the GDW one. The latter is a 6 m focal array firing hard X-Rays with a focal range of 2 light-seconds (1.2 million km). The Mongoose laser weapons use multiple small focal arrays and UV, and range is determined by the diameter of an individual FA element and the frequency. Given 2 m FA elements with UV, the focal range of a Mongoose laser is about 100 km. Normal guns are outranged by bomb-pumped nukes, and thus even with "area-defence" lasers, there is no defence against missiles.

Point-defence lasers are defined to have a range of adjacent (< 50 km in the AEH, < 100 km in the boxed set), and so are useless in all circumstances, especially as bomb-pumped nukes are defined as having a range of "close" (i.e. 150,000 km, which is unrealistic).

As a note, travel times are inconsistent in Mongoose, and apparently combat speeds are slower.

Anyway, the Mongoose turret lasers defy physics, since their stated range is far beyond what is possible with the frequencies involved. However, within the rules, they can at least attempt to engage incoming missiles, since they have the range range as det-warheads. However, the time needed to develop a firing solution means that counter-missile laser fire is going to be ineffective.

In the Mongoose rules, submunitions will be decisive. Cheap, a lot of damage, no range disadvantage, and no chance of point-defence.