Pondering starship evolution

[Spinward Flow]

I like the shift on the suite box. Nice.

It's one of those things where I had to do the "across the hall" version first in order to find this new one.

 

[Spinward Flow]

So here's a fun little bit of math (and the rabbit holes it opens).

I'm looking at the TL=9 D/D/D starship and I've basically got "two goals" to shoot for as far as performance goes.

• 800 / 1 = 800 tons = J1/1G/PP1
• 800 / 2 = 400 tons = J2/2G/PP2
• 800 / 3 = 266 tons = J3/3G/PP3

As worked out previously ... I can build a 250 ton starship, strap a 16 ton Escort Fighter to the exterior and get a 266 combined tons for a J3/3G performance profile. But what's especially interesting is how adding more 16 ton modules to that basic setup modifies drive performance as the external load increases.

• 250 + 16 = 266 = J3/3G/PP3
• 250 + 16 + 8*16 = 394 = J2/2G/PP2
• 250 + 16 + 33*16 = 794 = J1/1G/PP1

Where things get really interesting is in the realm of "buddy towing" other starships of the same class (up to 2!), externally. Some of the other "not the same starship class" alternatives get interesting as well.

• 250 + 1.1*100 + 2*16 = 392 = J2/2G/PP2
• 250 + 1.1*250 + 17*16 = 797 = J1/1G/PP1
• 250 + 1.1*250 + 1.1*250 = 800 = J1/1G/PP1
• 250 + 1.1*400 + 6*16 = 786 = J1/1G/PP1
• 250 + 1.1*500 = 800 = J1/1G/PP1

The downside to having a 250 ton starship design is the limited internal capacity for Boxes (no more than 4), which must be used for crew quarters (1 Box, minimum!) along with Passenger and Cargo capacity. So 3 Boxes for revenue tonnage @ J3 is a very tight fit, and remarkably limiting!

However, for J2 performance, the revenue tonnage increases from 3 Boxes to up to 11 (3 internal, up to 8 external).
The internal hangar bay is 64 tons.

---

Compare and contrast that with what happens in a 350 ton starship that can strap on 3 more Boxes to the exterior and get a 398 combines tons for J2/2G performance profile.

• 350 + 3*16 = 398 = J2/2G/PP2
• 350 + 28*16 = 798 = J1/1G/PP1

In this case, the "buddy towing" capacity of other starships of the same class, externally, is limited to just 1 ... but at the same time, the math is working out such that it is still possible to do some rather interesting combinations.

• 350 + 1.1*350 + 4*16 = 799 = J1/1G/PP1
• 350 + 1.1*400 = 790 = J1/1G/PP1

What gets interesting here is the revenue tonnage fraction. To keep the comparison equal, assume a single Box must be used for crew quarters (minimum 1!) and another "Box slot" will be available to the Escort Fighter so it can be docked internally. The internal hangar bay space is 176 tons (11x Boxes worth) total, and there is still capacity for up to 3 more Boxes to be docked externally while retaining a J2 drive performance output.

So for J2 performance, the revenue tonnage starts at 9 Boxes (internal) and can be increased to as many as 12 (9 internal, up to 3 external).

---

As you can see, from the way that the math is adding up, the 250 ton J3/3G version is possible to do ... technologically ... but the economics may dictate (if not subsidized) that the starship operated in a J2 (privately owned, paid off on delivery) or in a J1 (bank financed) capacity in order to make ends meet on ticket revenues alone. The drawback is a small internal load capacity (64 ton hangar bay).

Conversely, the 350 ton J2/2G version has a much larger internal load capacity (176 ton hangar bay) and doesn't need to dock the Escort Fighter to the starship's exterior during interstellar jumps. That larger revenue tonnage fraction then makes it a lot easier to sell more passenger and cargo freight tickets, but that larger capacity can potentially be "wasted" on routes with immature markets on low population worlds (a "right sizing" to demand issue).



The trick here is to realize that rather than designing for a single starship design, I've accidentally stumbled onto a design concept that ideally wants to be TWO starships, not just one.

The 350 ton J2/2G design is better for "high end" markets with larger volumes of trade ... while the 250 ton J3/3G design is better for "low end" markets with smaller volumes of trade ... so as to be able to better balance the competing signals of supply versus demand. Both designs use the same set of standard drives (D/D/D), but the 350 ton design works better on "preset routes" to fill its J2 capacity, while the 250 ton design works best as a speculative goods arbitrage tramp that can sell tickets (and move xmail) to prop up the bottom line between lucrative arbitrage runs.



It's also not lost on me that the 250 ton J3/3G design would also happen to be the "better choice" as a Corsair for a professional pirate.
Why?
Because of the larger external load capacity, enabling entire starships to be taken as prizes and jumped to unscrupulous shipyards that can liquidate the value of captures so as to turn them into credits and keep the party rolling. The Escort Fighter is just "too good" for most commercial shipping and thus there will always be the temptation to use them for nefarious ends. Also, the 3G maneuver performance is "what you'd want" in a Corsair anyway, in order to be able to intercept unsuspecting merchants more easily.

 

[Spinward Flow]

Taking a peek @ TL=10 once again, and THIS tumbled out of the math ...

---

307 tons starship hull
55 tons for LBB2.81 standard E/E/E drives (codes: 3/3/3, TL=10)
122.1 tons of total fuel: 307 tons @ J3 = 92.1 tons jump fuel + 30 tons power plant fuel
8 tons for TL=10 fuel purification plant (200 ton capacity is minimum)
20 tons for bridge
2 ton for model/2bis computer
97 tons for hangar berths capacity

1. Stateroom Box = 16 tons
2. Stateroom Box = 16 tons
3. Laboratory Box (Type V-c regenerative biome life support) = 16 tons
4. Environmental Box = 16 tons
5. Cargo Box = 16 tons
6. Cargo Box = 16 tons
7. 97 tons capacity Collapsible Fuel Tank = 0.97 tons

External Docking Capacity: 672 tons

1. Escort Fighter = 16 tons

2.9 tons for Cargo Hold(s)

= 55+122.1+8+20+2+97+2.9 = 307 tons + 16 tons (Escort Fighter) = 323 tons
5 Crew: Pilot/Navigator, Ship's Boat/Gunner, Engineer/Engineer, Steward/Steward, Medic
Revenue Tonnage: 3x high passengers + 16 tons environmentally controlled cargo + 32 tons standard cargo
Escort Fighter external

---

So why might that be an interesting result (mathematically speaking)?
Well ...

• 307 + 1*16 = 323 tons = J3/3G/PP3
• 307 + 12*16 = 499 tons = J2/2G/PP2
• 307 + 43*16 = 995 tons = J1/1G/PP1

Okay, that's "nice" for 16 ton small craft in modular blocks (of no more than 6x 16 tons = 96 combined tons each), but what about needing to externally tow big craft?

• 307 + 1.1*100 + 5*16 = 497 tons = J2/2G/PP2
• 307 + 1.1*160 + 1*16 = 499 tons = J2/2G/PP2
• 307 + 1.1*307 + 1.1*307 + 1*16 = 998.4 tons = J1/1G/PP1
• 307 + 1.1*600 + 2*16 = 999 tons = J1/1G/PP1

---

Compare and contrast that kind of performance with what is possible @ TL=9.

---

250 tons starship hull
45 tons for LBB2.81 standard D/D/D drives (codes: 3/3/3, TL=9)
105 tons of total fuel: 250 tons @ J3 = 75 tons jump fuel + 30 tons power plant fuel
9 tons for TL=9 fuel purification plant (200 ton capacity is minimum)
20 tons for bridge
2 ton for model/2bis computer
64 tons for hangar berths capacity

1. Stateroom Box = 16 tons
2. Stateroom Box = 16 tons
3. Cargo Box = 16 tons
4. Cargo Box = 16 tons

External Docking Capacity: 550 tons capacity

1. Escort Fighter = 16 tons

5 tons Cargo Hold

• 4 tons for Air/Raft
• 0.36 tons for 54 person/weeks Life Support Reserves
• 0.64 tons for 64 tons capacity Collapsible Fuel Tank

= 45+105+9+20+2+64+5 = 250 tons
4 Crew: Pilot/Navigator, Ship's Boat/Gunner, Engineer/Engineer, Steward/Medic
4 high passengers, 32 tons standard cargo internal
Escort Fighter external

---

For the external towing of small craft, the breakpoints fall out like so:

• 250 + 1*16 = 266 = J3/3G/PP3
• 250 + 9*16 = 394 = J2/2G/PP2
• 250 + 34*16 = 794 = J1/1G/PP1

And for big craft, you get the following:

• 250 + 1.1*100 + 2*16 = 392 = J2/2G/PP2
• 250 + 1.1*250 + 17*16 = 797 = J1/1G/PP1
• 250 + 1.1*250 + 1.1*250 + 0*16 = 800 = J1/1G/PP1
• 250 + 1.1*400 + 6*16 = 786 = J1/1G/PP1
• 250 + 1.1*500 + 0*16 = 800 = J1/1G/PP1

---

So while it is POSSIBLE to build a J3/3G Clipper @ TL=9, it's really "too cramped for its own good" in terms of hangar bay capacity (and thus revenue tonnage fraction) when compared to the TL=10 alternative.

In terms of ticket revenues on a 100% manifest @ J3/3G:

• TL=10 ... Cr30,000 for 3x high passengers + Cr48,000 for 48 tons cargo freight = Cr78,000 per jump
• TL=9 ... Cr40,000 for 4x high passengers + Cr32,000 for 32 tons cargo freight = Cr72,000 per jump

However, a BIG difference is going to be the life support expenses between the two designs.

• TL=10 ... Cr0 for 8 single occupancy staterooms (Type V-c regenerative biome life support) every 2 weeks
• TL=9 ... Cr16,000 for 8 single occupancy staterooms every 2 weeks

Which means that the net balance (unsubsidized) at a 1 jump per 2 weeks tempo starts looking like this:

• TL=10 ... 78,000 - 0 = Cr78,000
• TL=9 ... 72,000 - 16,000 = Cr56,000

Subsidized service (50% rake of ticket revenues) makes the comparison look even worse for the TL=9 version's economics:

• TL=10 ... 78,000/2 - 0 = Cr39,000
• TL=9 ... 72,000/2 - 16,000 = Cr20,000

That's because under subsidy, the ticket revenues are cut in half (50% rake for the subsidizing government) but the operating expenses (crew salaries, life support, berthing fees, annual maintenance, etc.) all remain at 100%.

So on the TL=9 version, if you swap out 1 of the 2 Cargo Boxes for a Laboratory Box (Type V-c regenerative biome life support, you cut your cargo capacity IN HALF from 32 tons (barely adequate for speculative goods opportunities) all the way down to 16 tons (you'll miss out on a lot of speculative goods opportunities due to a lack of transport capacity).

Your ticket revenues would do this:

• TL=9 ... Cr40,000 for 4x high passengers + Cr16,000 for 16 tons cargo freight = Cr56,000 per jump

Your unsubsidized net balance at 1 jump per 2 weeks tempo looks like this:

• TL=9 ... 56,000 - 0 = Cr56,000

And your subsidized net balance at 1 jump per 2 weeks tempo looks like this:

• TL=9 ... 56,000/2 - 0 = Cr28,000

So better on the ticket revenues, but (much) worse on the speculative goods arbitrage front due to the reduction in cargo capacity (hence why I considered and discarded the option for the TL=9 design @ 250 tons, there just isn't enough "spare room" to make it practical). However, this IS an example of how investment into regenerative biome life support options can "pay for themselves" in terms of offsetting life support overhead expenses for starship operators.



Obviously both ships would be working the "small time/low end" trading market, going to low(-ish) population worlds with limited demand for ticket services while configured for J3/3G. However, when the opportunity (or market demand) rises, loading up with external third party Boxes that need to be towed to a destination will always be an option, increasing ticket revenues in exchange for a reduction in drive performance.

It also highlights the notion that starships "need to be a certain minimum size" (and therefore, technology level) before a whole range of options for business models become available and/or practical.

 

[Spinward Flow]

97 tons for hangar berths capacity

1. Stateroom Box = 16 tons
2. Stateroom Box = 16 tons
3. Laboratory Box (Type V-c regenerative biome life support) = 16 tons
4. Environmental Box = 16 tons
5. Cargo Box = 16 tons
6. Cargo Box = 16 tons
7. 97 tons capacity Collapsible Fuel Tank = 0.97 tons

Okay.
Now I think I'm onto something here.

This 97 ton hangar bay for 6x 16 ton Boxes plus a 97 tons capacity Collapsible Fuel Tank is just ... elegant ... as a bit of mathematical design. Enough so that I'm thinking it ought to be the "standard feature" for a J2/2G design @ TL=9 AND for a J3/3G design @ TL=10. This would then create an "upgrade path" in capabilities when moving from TL=9 to TL=10 and represent a sort of natural progression.

Here's how the "spreadsheet math" for all of that works out on the napkin.

---

232 tons starship hull
35 tons for LBB2.81 standard C/C/C drives (codes: 2/2/2, TL=9)
67 tons of total fuel: 232 tons @ J2 = 46.4 tons jump fuel + 20 tons power plant fuel
9 tons for TL=9 fuel purification plant (200 ton capacity is minimum)
20 tons for bridge
2 ton for model/2 computer
97 tons for hangar berths capacity

1. Stateroom Box = 16 tons
2. Stateroom Box = 16 tons
3. Laboratory Box (Type V-c regenerative biome life support) = 16 tons
4. Environmental Box = 16 tons
5. Cargo Box = 16 tons
6. Cargo Box = 16 tons

• 97 tons capacity Collapsible Fuel Tank = 0.97 tons

External Docking Capacity: 368 tons capacity

1. Escort Fighter = 16 tons
2. 
   
3. 
   

2 tons for Cargo Hold
= 35+67+9+20+2+97+2 = 232 tons + 16 tons (Escort Fighter) = 248 tons

Crew = 5
1. Pilot-2/Navigator-2
2. Ship's Boat-2/Gunner-2
3. Engineer-1
4. Steward-1/Steward-1
5. Medic-3
Revenue Tonnage @ J2
• 3x high passengers
• 16 tons environmentally controlled cargo
• 32 tons standard cargo
• 48 tons additional cargo (when 1x Environmental and 2x Cargo Boxes moved to exterior)
Revenue Tonnage @ J2+2
• 3x high passengers
• 16 tons environmentally controlled cargo
• 32 tons standard cargo
Escort Fighter external

---

And to do the (now obligatory) math for external towing:

• 232 + 1*16 = 248 tons = J2/2G/PP2
• 232 + 4*16 = 296 tons = J2/2G/PP2
• 232 + 23*16 = 600 tons = J1/1G/PP1
• 232 + 1.1*200 + 9*16 = 596 tons = J1/1G/PP1
• 232 + 1.1*232 + 7*16 = 599.2 tons = J1/1G/PP1
• 232 + 1.1*300 + 2*16 = 594 tons = J1/1G/PP1

---

The incredible thing about THIS iteration is that it is capable of J2+2 by moving 3x Boxes (usually the Environmental and Cargo) from the interior hangar to exterior docking points, freeing up 48 tons of internal hangar volume to be occupied by a partial fill of the collapsible fuel tank with 48 tons of fuel.

• 67 + 48 = 115 tons of combined total fuel load

Where things get interesting is computing the jump fuel demands.

• (232+4*16)*0.2 = 59.2 tons for first J2 ... move 3x Boxes from exterior to interior during 16 hour routine drive maintenance after jump
• (232+1*16)*0.2 = 49.6 tons for second J2

59.2+49.6 = 108.8 tons of jump fuel required for J2+2
115 tons of combined total fuel from point of origin

In other words, this design can J2+2 @ TL=9 at a "cost" of 48 tons of cargo freight ticket(s) revenue.



This looks REALLY PROMISING as a Long Trader design.
Being able to get 4 parsecs of range out of a TL=9 design makes all kinds of speculative goods arbitrage opportunities possible within reasonable time frames for tramp merchant operators.

---

---

---

The "upgrade" to that then becomes THIS @ TL=10 ...

---

307 tons starship hull
55 tons for LBB2.81 standard E/E/E drives (codes: 3/3/3, TL=10)
123 tons of total fuel: 307 tons @ J3 = 92.1 tons jump fuel + 30 tons power plant fuel
8 tons for TL=10 fuel purification plant (200 ton capacity is minimum)
20 tons for bridge
2 ton for model/2bis computer
97 tons for hangar berths capacity

1. Stateroom Box = 16 tons
2. Stateroom Box = 16 tons
3. Laboratory Box (Type V-c regenerative biome life support) = 16 tons
4. Environmental Box = 16 tons
5. Cargo Box = 16 tons
6. Cargo Box = 16 tons

• 97 tons capacity Collapsible Fuel Tank = 0.97 tons

External Docking Capacity: 693 tons

1. Escort Fighter = 16 tons

2 tons for Cargo Hold(s)

= 55+123+8+20+2+97+2 = 307 tons + 16 tons (Escort Fighter) = 323 tons
Crew = 5

1. Pilot-2/Navigator-2
2. Ship's Boat-2/Gunner-2
3. Engineer-2/Engineer-2
4. Steward-1/Steward-1
5. Medic-3

Revenue Tonnage @ J3

• 3x high passengers
• 16 tons environmentally controlled cargo
• 32 tons standard cargo

Escort Fighter external

---

And to do the (now obligatory) math for external towing:

• 307 + 1*16 = 323 tons = J3/3G/PP3
• 307 + 12*16 = 499 tons = J2/2G/PP2
• 307 + 43*16 = 995 tons = J1/1G/PP1
• 307 + 1.1*100 + 5*16 = 497 tons = J2/2G/PP2
• 307 + 1.1*400 + 15*16 = 987 tons = J1/1G/PP1
• 307 + 1.1*600 + 2*16 = 999 tons = J1/1G/PP1

---

The interesting thing here is that this TL=10 upgrade is capable of doing a J2+3 using its collapsible fuel tank, among other possible permutations depending on external load factors, making this upgrade version "even better" for a lot of speculative goods arbitrage tramp merchant operators. More range and increased load capacity (because of more powerful drives) makes for enough of a "step change" in capability as to be worthy of a revised and updated design.



Which means that I think I've finally got my TL=9-10 design path details settled (finally).

 

[aramis]

Spinward Flow - which ruleset are you using for these? (it makes HUGE differences in the math.)

 

[kilemall]

Piracy is just servicing an alternative market for goods at a low fiscal but high risk rate.

Star Citizen has a starship builder that specializes in dual purpose ships that can be rescue, haulers, LE, defense etc but has found a ready market in pirates. So they even play to that market with named ship classes like Cutlass, Corsair, etc.

Drake Interplanetary - Star Citizen Wiki

Drake Interplanetary is a Human spacecraft manufacturer that designs, manufacturers and sells spaceships in the Star Citizen universe. It is headquartered in Odyssa...

starcitizen.tools

 

[Spinward Flow]

Spinward Flow - which ruleset are you using for these? (it makes HUGE differences in the math.)

LBB2.81 (drives and weapons)
LBB3.81 (drive TLs and vehicles)
LBB5.80 (hull configurations, EP system, computers, fuel purification plants, sub-craft and hangars, etc.) (all the stuff that LBB2.81 "doesn't do")
LBB A5 (collapsible/demountable/drop fuel tanks)

Homebrew (to interpolate the gaps in CT RAWs)

• LBB2.81 Drive Performance Formula plus External Load Towing Capacity rules for starships
• Regenerative Life Support Biome rules for starships

ALL of these sources have been consistent (from me) during the continuity of this thread.

The reason why I didn't put a "CT Only" or even a "Rules Only" marker on this thread is because I'm blending in some homebrew into CT, so from a strictly purist/fundamentalist point of view, what I'm doing is merely "CT Adjacent" because I'm doing things that the RAW doesn't address (properly) in order to make a Cool New Thing™.



As for any kind of precedent to the notion that it's possible to "tow" external loads through jump (like I'm appealing to here) ... I give you LBB S9, p22-23 ... the Jump Ship ... which is a 5000 ton starship class designed to "tow" 1000 ton external pods or other "bulk matter" as needed.

There's also the precedent (exceedingly poorly explained!) of External Demountable Tanks as well as Drop Tanks, both of which alter the displacement of craft and both of which can be retained through jump (Demountable Tanks must be retained, Drop Tanks can be optionally retained). The (confusing in its particulars) Gazelle-class is an example of a starship that has different drive performance levels depending upon external loading kept close to the hull.



Does that answer your question?

 

[Spinward Flow]

97 tons for hangar berths capacity

1. Stateroom Box = 16 tons
2. Stateroom Box = 16 tons
3. Laboratory Box (Type V-c regenerative biome life support) = 16 tons
4. Environmental Box = 16 tons
5. Cargo Box = 16 tons
6. Cargo Box = 16 tons

• 97 tons capacity Collapsible Fuel Tank = 0.97 tons

Here's what the contents of such hangar bays look like when drawn as deck plans, so that the context of what I'm building towards starts getting clearer.

You have a double deck height hangar bay (left of picture is forward, right of picture is aft).

• 3 Boxes dorsal (environment, cargo, cargo)
• 3 Boxes ventral (stateroom, laboratory, stateroom)

Right now, I'm thinking that you would want to have a single aft door (horizontal axis hinge, ventral) which can be used as a ramp for loading/unloading from the ground ... while also having clamshell doors (split down the middle, open to port/starboard) on the dorsal for vertical "crane" lifting in/out of the hangar bay, such as by the Escort Fighter while the starship is parked in a gravity well or by starport facilities when in a berth.

Obviously, the next step is to start drawing the hangar bay facilities "around" the Boxes, which will also include the built in collapsible fuel tank "stuffs™" ... but this at least forms the core of what the rest of the starship design(s) needs to get built around. It therefore makes for a decent beginning for everything that follows after as I build towards completed deck plans for TWO starship classes that will have this specific hangar bay detail in common between them.

• 232 ton starship with C/C/C drives delivering J2/2G/PP2 performance @ TL=9
• 307 ton starship with E/E/E drives delivering J3/3G/PP3 performance @ TL=10

---

Out of curiosity, I test the notion of "extending the run" to J/J/K drives delivering J4/4G/PP4 performance @ TL=11 ... and ran into a problem.

98 tons for LBB2.81 standard J/J/K drives (codes: 4/4/4, TL=11) (Agility=4)
40 tons power plant fuel
7 tons for TL=11 fuel purification plant (200 ton capacity is minimum)
20 tons for bridge
4 ton for model/4 computer (requires EP=2, hence why power plant-K is required)
97 tons for hangar berths capacity

1. Stateroom Box = 16 tons
2. Stateroom Box = 16 tons
3. Laboratory Box (Type V-c regenerative biome life support) = 16 tons
4. Environmental Box = 16 tons
5. Cargo Box = 16 tons
6. Cargo Box = 16 tons

• 97 tons capacity Collapsible Fuel Tank = 0.97 tons

98+40+7+20+4+97 = 266 "uncompressible" tons

If I take that 266 tons number and then divide by 0.6, so as to calculate the minimum tonnage needed to include a 40% jump fuel fraction, the answer that comes out of the math is ... 266/0.6 = 443.333 ... round up to 444 tons minimum.

J-drives for jump and maneuver have the following performance breakpoints:

• Code: 1 @ 1800 tons
• Code: 2 @ 900 tons
• Code: 3 @ 600 tons
• Code: 4 @ 450 tons

The problem is that there isn't enough "margin" left over, between 444 and 450 tons, for the Escort Fighter to be carried externally any more.

At that point, you either have to trade in one (or both) of the Cargo Boxes for either a TL=9 Escort Fighter (1 Box) or a TL=11 Escort Fighter (2 Boxes) so that the Escort Fighter can be carried internally.

In other words, "carrying the trend this far forward" into TL=11 is ... problematic ... especially since +1 Engineer position is required for drives of that size, reducing the high passenger stateroom accommodations from 3 to 2, so not only is the starship getting a LOT more expensive, the revenue tonnage fraction is dropping as well, pushing everything towards being uneconomical @ J4 on ticket revenues alone (which is not surprising, all things considered).

---

Alternatively, I could do this:

105 tons for LBB2.81 standard K/K/K drives (codes: 4/4/4, TL=11) (Agility=3, Emergency Agility=4)
40 tons power plant fuel
7 tons for TL=11 fuel purification plant (200 ton capacity is minimum)
20 tons for bridge
4 ton for model/4 computer (requires EP=2, hence why power plant-K is required)
97 tons for hangar berths capacity

1. Stateroom Box = 16 tons
2. Stateroom Box = 16 tons
3. Laboratory Box (Type V-c regenerative biome life support) = 16 tons
4. Environmental Box = 16 tons
5. Cargo Box = 16 tons
6. Cargo Box = 16 tons

• 97 tons capacity Collapsible Fuel Tank = 0.97 tons

105+40+7+20+4+97 = 273 "uncompressible" tons

If I take that 273 tons number and then divide by 0.6, so as to calculate the minimum tonnage needed to include a 40% jump fuel fraction, the answer that comes out of the math is ... 273/0.6 = 455 (exactly).

K-drives for jump and maneuver have the following performance breakpoints:

• Code: 1 @ 2000 tons
• Code: 2 @ 1000 tons
• Code: 3 @ 666 tons
• Code: 4 @ 500 tons

From a "buddy towing" other starships of the same class perspective, 460 tons is probably the "sweet spot to land on, because:

• 460 + 1.1*460 + 2*16 = 998 tons = J2/2G/PP2 (Agility=1, Emergency Agility=2)

Once you go past 1000 tons of combined displacement, small craft stop being carried at their own tonnage (LBB5.80, p32) ... but if they're "docked together" in sufficient quantities (100+ combined tons per "block" of Boxes), then they can be externally towed as Big Craft (110%) rather than as Small Craft (130%) due to packing efficiencies.

And it's at this point that 460 tons of starship with K/K/K drives starts looking like QUITE the "sweet spot" mathematically speaking.
Why?
Well ... because ...

• 2000 - 460 = 1540 / 1.1 = 1400 tons of big craft external towing capacity @ J1/1G/PP1 (Agility=0, Emergency Agility=1)

The math starts getting a bit complex with all of the possible permutations of external loading , but suffice it to say that 460 tons @ TL=11 is looking like the "natural end point" for the Trend Line of capabilities that I've been researching here. The revenue tonnage fraction of the overall hull (at J-max) is getting increasingly small, while the construction costs are ballooning quite dramatically(!) ... so RANGE HAS ITS PRICE in this context. However, it would be possible (potentially even desirable!) to operate such a starship as a speculative goods arbitrage tramp, in order to sustain a profitable merchant operation. Additionally, the external load capacity starts getting SO LARGE that you start moving out of the ACS realm of penny ante Free Trader operations and start needing to move into the structured merchant company operations model that needs more extensive "support" in terms of outside expertise (and third party relationships) in order to fill manifests economically.

In other words, the "small time operator" paradigm starts breaking down by TL=11 and you start needing to move towards more of a "bulk freighter" mindset that the Big Boys™ use (see: megacorporations). At that point, the "speculative goods arbitrage" is what is driving everything, but the starship operators aren't "controlling" the production and procurement of the speculative goods ... instead, third parties are doing that (or in the case of megacorporations, other divisions within the same company). That way, the starship (and her crew) can be operated "at a loss" on the books, while the (speculative goods cargo) freight gets transported at a profit ... potentially enough of a profit to cover the operational overhead expenses incurred by the operation of the starship ... at which point net profits turn into a bit of a shell game going on between multiple aligned interests/divisions within the same company (or affiliated companies). Even a profit sharing arrangement with third parties, allowing starship operators to "take a cut" of any speculative goods arbitrage the third party is engaging in, can easily manage to "balance the books" for a tramp merchant that is prioritizing partner business relationships on each world that the starship routinely visits (one of those "keep it in the family" deals).

 

[Spinward Flow]

Okay.
Now I think I'm onto something here.

This 97 ton hangar bay for 6x 16 ton Boxes plus a 97 tons capacity Collapsible Fuel Tank is just ... elegant ... as a bit of mathematical design. Enough so that I'm thinking it ought to be the "standard feature" for a J2/2G design @ TL=9 AND for a J3/3G design @ TL=10. This would then create an "upgrade path" in capabilities when moving from TL=9 to TL=10 and represent a sort of natural progression.

I was looking at math for both of these designs ... and thinking that I was close to optimal, but there was still a little bit of wiggle room to squeeze out a smidgen more capability.

The key point was the "leftover 2 tons" for the cargo hold in both designs, which seems like a strange thing to quibble over, I know.

But after taking some more time to think about it, I realized that what I REALLY wanted there was actually a 5 ton cargo hold, not just 2 tons.
So why 5 tons?
Well ...

A 5 ton cargo hold is "conveniently sized" to be either an x-mail vault ... or an air/raft berth with a 1 ton remainder for anything else that might "fit" into that space (including 2x low berths or 1x emergency low berth). The convenience there is that not every starship is going to be eligible for postal contracts (or want to deal with the "hassles" of carrying x-mail), or the mission profile for an individual starship will make a poor fit for making x-mail deliveries (such as a Search & Rescue equipped ship and crew). The important point is to make the OPTION available, even if that option is not exercised in every instance by every operator of the class. The flexibility to make that choice an option is what is important.

Likewise, for some tramp operators (particularly those who flirt with illegality), when speculative goods arbitrage on the fringes of civilization is a priority, being able to dabble in the "small package trade" (a euphemism for smuggling) from time to time starts becoming rather attractive. Operators who intend to service "austere" locations (D and E starports mainly, but we don't talk about type X starports) where local services can be "lacking" ... bringing along your own air/raft as a vehicle runabout and cargo marshaling assistant makes a lot more sense.

So I bumped the tonnages for both designs upwards just enough to be able to fit a 5 ton cargo bay into the J2/2G/PP2 TL=9 and the J3/3G/PP3 TL=A versions. Here's how the spreadsheet for both classes shakes out when doing the math.

---

Rule of Man Long Trader (TL=9)
236 tons starship hull, configuration: 1
35 tons for LBB2.81 standard C/C/C drives (codes: 2/2/2, TL=9)
68 tons of total fuel: 232 tons @ J2 = 47.2 tons jump fuel + 20(.8) tons power plant fuel
9 tons for TL=9 fuel purification plant (200 ton capacity is minimum)
20 tons for bridge
2 tons for model/2 computer
97 tons for hangar berths capacity

1. Environmental Box = 16 tons
2. Cargo Box = 16 tons
3. Cargo Box = 16 tons
4. Stateroom Box = 16 tons
5. Laboratory Box (Type V-c regenerative biome life support) = 16 tons
6. Stateroom Box = 16 tons

• 97 tons capacity Collapsible Fuel Tank = 0.97 tons

* External Docking: 364 tons capacity

1. Escort Fighter = 16 tons
2. 
   
3. 
   

5 tons for Cargo Hold

= 35+68+9+20+2+97+5 = 236 tons + 16 tons (Escort Fighter) = 352 combined tons

Crew = 5

1. Pilot-2/Navigator-2
2. Ship's Boat-2/Gunner-2
3. Engineer-1
4. Steward-1/Steward-1
5. Medic-3

Revenue Tonnage @ J2

• 3x high passengers
• 16 tons environmentally controlled cargo
• 16+16+5=37 tons standard cargo
• 48 tons additional cargo (when 1x Environmental and 2x Cargo Boxes moved to exterior)

Revenue Tonnage @ J2+2

• 3x high passengers
• 16 tons environmentally controlled cargo
• 16+16+5=37 tons standard cargo

Escort Fighter external

Drive Performances with External Loading

• 236 + 4*16 = 300 tons = J2/2G/PP2
• 236 + 22*16 = 588 tons = J1/1G/PP1
• 236 + 1.1*100 + 15*16 = 586 tons = J1/1G/PP1
• 236 + 1.1*200 + 9*16 = 600 tons = J1/1G/PP1
• 236 + 1.1*236 + 6*16 = 591.6 tons = J1/1G/PP1
• 236 + 1.1*300 + 2*16 = 598 tons = J1/1G/PP1

---

Escort Fighter (TL=9)
16 ton small craft hull, configuration: 1
5 tons for LBB2.81 standard A/A drives (codes: 6/6, TL=9, EP=2) (Agility=6)
1 ton for fuel (09d 21h 17m endurance)
4 tons for bridge (includes 2x acceleration couches for 2x workstations)
3 tons for model/3 computer (TL=9, EP: 1)
1 ton for mixed triple turret: missile, sandcaster, missile (TL=9, codes: 1/2/1, EP: 0)
2 tons for 1x small craft stateroom
* External Docking: 184 tons capacity

= 5+1+4+3+1+2 = 16 tons

Crew = 1

1. Ship's Boat-2/Gunner-2

---

---

Rule of Man Clipper (TL=10)
310 tons starship hull, configuration: 1
55 tons for LBB2.81 standard E/E/E drives (codes: 3/3/3, TL=A)
123 tons of total fuel: 310 tons @ J3 = 93 tons jump fuel + 30 tons power plant fuel
8 tons for TL=10 fuel purification plant (200 ton capacity is minimum)
20 tons for bridge
2 tons for model/2bis computer
97 tons for hangar berths capacity

1. Stateroom Box = 16 tons
2. Stateroom Box = 16 tons
3. Laboratory Box (Type V-c regenerative biome life support) = 16 tons
4. Environmental Box = 16 tons
5. Cargo Box = 16 tons
6. Cargo Box = 16 tons

• 97 tons capacity Collapsible Fuel Tank = 0.97 tons

* External Docking: 690 tons capacity

1. Escort Fighter = 16 tons

5 tons for Cargo Hold

= 55+123+8+20+2+97+5 = 310 tons + 16 tons (Escort Fighter) = 326 combined tons

Crew = 5

1. Pilot-2/Navigator-2
2. Ship's Boat-2/Gunner-2
3. Engineer-2/Engineer-2
4. Steward-1/Steward-1
5. Medic-3

Revenue Tonnage @ J3

• 3x high passengers
• 16 tons environmentally controlled cargo
• 16+16+5=37 tons standard cargo

Escort Fighter external

Drive Performances with External Loading

• 310 + 1*16 = 326 tons = J3/3G/PP3
• 310 + 11*16 = 486 tons = J2/2G/PP2
• 310 + 43*16 = 998 tons = J1/1G/PP1
• 310 + 1.1*100 + 5*16 = 500 tons = J2/2G/PP2
• 310 + 1.1*200 + 29*16 = 994 tons = J1/1G/PP1
• 310 + 1.1*300 + 22*16 = 992 tons = J1/1G/PP1
• 310 + 1.1*310 + 21*16 = 987 tons = J1/1G/PP1
• 310 + 1.1*400 + 15*16 = 990 tons = J1/1G/PP1
• 310 + 1.1*500 + 8*16 = 988 tons = J1/1G/PP1
• 310 + 1.1*600 + 1*16 = 986 tons = J1/1G/PP1

---

Escort Fighter (TL=A)
16 ton small craft hull, configuration: 1
5 tons for LBB2.81 standard A/A drives (codes: 6/6, TL=9, EP=2) (Agility=6)
1 ton for fuel (09d 21h 17m endurance)
4 tons for bridge (includes 2x acceleration couches for 2x workstations)
3 tons for model/3 computer (TL=9, EP: 1)
1 ton for mixed triple turret: missile, sandcaster, missile (TL=A, codes: 1/3/1, EP: 0)
2 tons for 1x small craft stateroom
* External Docking: 184 tons capacity

= 5+1+4+3+1+2 = 16 tons

Crew = 1

1. Ship's Boat-2/Gunner-2

---

---

The tech levels (9-A) on these designs are "low enough" to be plausible Solomani Second Imperium (pre-Long Night) tramp merchant classes competing with the older Vilani J1 Free Trader and J2 Far Trader class designs.

There isn't anything "inherently special" about these starship classes, in terms of unique technologies that are only found in limited pockets of charted space (or whatever). There's no "hyper military grade" technology involved (necessarily) which can be classified as "state secrets" that would prevent the class details from being copied/duplicated/recreated by different shipyards in different regions in different eras using local industrial bases. By the time that TL=C is starting to become widespread, both of these starship classes (TL=9-A) would very much be considered "civilian commercial grade" tech.

The Escort Fighter will undoubtedly have paramilitary (if not outright military) tech involved with its bridge/computer and weapon systems, since it IS a fighter design (go figure... ), but as technology levels advance beyond 9-A it will rapidly become "obsolete" in comparison to (cutting edge, higher tech level) military fighters on par with their tech level (which will need bigger displacements to accommodate increasingly powerful computers and larger power plants to supply the necessary EP for everything).

 

[Spinward Flow]

So I bumped the tonnages for both designs upwards just enough to be able to fit a 5 ton cargo bay into the J2/2G/PP2 TL=9 and the J3/3G/PP3 TL=A versions. Here's how the spreadsheet for both classes shakes out when doing the math.

And ... I just finished doing up the construction costs for both versions.

---

J2/2G/PP2 TL=9 @ 236 ton starship + 16 ton Escort Fighter + 2x Stateroom Box + 1x Laboratory Box + 1x Environment Box + 2x Cargo Box
Single Production (100% construction cost): Cr155,881,700
Volume Production (80% construction cost): Cr125,394,000

---

J3/3G/PP3 TL=10 @ 310 ton starship + 16 ton Escort Fighter + 2x Stateroom Box + 1x Laboratory Box + 1x Environment Box + 2x Cargo Box
Single Production (100% construction cost): Cr218,857,700
Volume Production (80% construction cost): Cr175,774,800

---

All things considered, that is not too shabby ... even if I do so say so myself.

The J2/2G/PP2 version is not that far off the construction price of a J1 Fat Trader @ MCr101.035 (LBB2.81, p19 and LBB S7, p47) plus the MCr14 for the latter's 20 ton Launch small craft (LBB S7, p47).

So, basically, the Rule of Man Long Trader class costs MCr10.359 more in volume production construction price ... but you get a much more capable and well protected ship that can "survive" more easily on routes to backwater/low population star systems and operate more "easily" as a tramp merchant pursuing speculative goods arbitrage opportunities in "less permissive/friendly environments" when compared to Vilani designs. Being able to J2+2 also makes a pretty significant difference in "reach" capabilities, compared to the J1 Fat Trader when it comes to "marrying up" sources of supply with destinations of demand in the arbitrage of speculative goods.

The J3/3G/PP3 version, known as the Rule of Man Clipper class, is commensurately more expensive than its predecessor (+40.2% actually), but the increase in external load capacity and/or range makes the upgrade a rather dramatic improvement in capabilities and options, even at these relatively modest tech levels.



Of course, rivals to and detractors of the classes will style them as the Ramshackle Long Trader and the Ramshackle Clipper classes (respectively), but that's typically taken as a sign of envy and jealousy (of the "telling on yourself" variety) towards the classes and their crews, rather than as an honest criticism of the merits of each class (let alone their capabilities).

 

[Spinward Flow]

Was doing a little bit more Review & Evaluation of the deck plans for the core of this modularized Box transport idea and decided to "shave off the corners" of those TL=9 Boxes. I would like to think that the results, while superficial (and superfluous) to spreadsheet work in the Naval Architect's Office, will make for an overall much more pleasing presentation when I start building everything up into actual deck plans for the TL=9 and TL=10 starships.

Cargo and Environment Boxes

Laboratory Box (regenerative biome life support type)

Stateroom Box (multiple types)

So the modification at the outer corners can barely be seen in the above images. The bevel/rounding of the outer corners is extremely easy to overlook, but it is there.

However, it gets a lot easier to discern and see when the Boxes get put into their proper context of a 3x2 double deck stack of them for loading into a hangar bay (or cargo hold) as a 6x16=96 tons combined "package" of Boxes.

So it's still a subtle change, but one that modifies perception just enough to be aesthetically pleasing.
For comparison, here is the previous "hangar bay layout" image with rigidly square outer corners on the Boxes.

Just wanted to share that extremely minor tidbit of deckplan design engineering.

 

[atpollard]

Was doing a little bit more Review & Evaluation of the deck plans for the core of this modularized Box transport idea and decided to "shave off the corners" of those TL=9 Boxes. I would like to think that the results, while superficial (and superfluous) to spreadsheet work in the Naval Architect's Office, will make for an overall much more pleasing presentation when I start building everything up into actual deck plans for the TL=9 and TL=10 starships.

I remember reading about a discussion concerning the original "Macintosh" operating system and the [ROUNDRECT] function. There was an internal debate about the importance of the ability to create a rectangle with rounded corners as innate to the operating system. The one designer that was adamant that it MUST be included dragged the design team outside for a tour of the real world to point out just how many objects are actually rounded corners rather than sharp angles. That convinced the team and the rounded corner buttons became iconic to GUI.

This is similar. Real modules [unless made by Tesla ] will have non-sharp edges. So WELL DONE!

 

[Spinward Flow]

So I had a bit of free time and decided to start plotting out the main deck features for where "everything has to go" in order to make stuff fit together. This is just the first draft (obviously) and features only the main deck hangar bay (without the side wall automation bits and collapsible fuel tank storage, yet) so as to get myself oriented as to how things "need" to fit together this time.

Reminder for anyone who needs it that this is an overhead "top-down" view:

• Left = Forward
• Right = Aft
• Bottom = Port
• Top = Starboard
• Near (out of the screen) = Dorsal
• Far (behind the screen) = Ventral

Now, I'm sure that some followers (if there are still any ... ) of this thread will be looking at that preliminary image and wondering ... why THAT arrangement?

Well, this is where Picture vs 1000 Words comes in handy, to make things clear(er) ... but words still help with the explanation.
So ... picture first.

What you're looking at in this second image is overlaying the Cargo Box iconography on top of the first image that I showed above.
This is how the position for the vertical access points got determined.

The hangar bay itself is only 3x Boxes long, but I then positioned 2x Boxes forward of the hangar bay so as to determine where the furthest forward (probably forward of the bridge, now that I think about it) vertical access point is going to need to be. This "forward-most" grav lift point then becomes the natural external docking point for the Escort Fighter on the dorsal outer hull when the two are hard docked to each other.

The port/starboard vertical access points (over/under the wings) have the Boxes rotated 90º so they will "stack outboard" in groupings of up to 3 long by 2 high, so that each "array" of linked Boxes is no more than 6x16=96 tons per vertical axis docking point via the wing.

Previous designs arrayed the Boxes in a longitudinal arrangement stretching from fore to aft. The downside of the fore/aft arrangement was that it "forced" large arrays of Boxes to be compiled into blocks exceeding 100 tons per grouping over/under the wings. This new arrangement will enable 2 dorsal and 2 ventral block arrays of 6x16 ton Boxes on both the port and starboard wings (for a total of 8 wing docking locations). The forward (of the bridge?) docking point on the centerline will permit both dorsal and ventral docking with the 16 ton Escort Fighter (dorsal) and any "remainder" of 16 ton Boxes that cannot be evenly divided between the wing docking points for specific external load configurations.

Obviously, the streamlined hull of the starship becomes "unstreamlined" while external loads are docked to it (just like is the case with External Demountable Fuel Tanks, see: LBB A5, p14 if unsure of the precedent). This means that the external docking points are only used while in orbit.

In order to transfer external loads between orbit and a world surface, the external load (of 16 ton Boxes) needs to be transferred into the internal hangar bay (3 on the upper deck, 3 on the main deck) for any orbit to surface/surface to orbit transfers. Basically, the starship operates as its own 2G/3G "orbital shuttle service" for moving Boxes (6 per shuttle run) up/down a planetary gravity well (regardless of atmosphere). This allows the Configuration: 1 starship to cleanly maneuver through atmosphere, unencumbered by external factors and complete orbital transport relays until all of the external load of Boxes have been moved.

The Escort Fighter typically remains in a classical High Guard position during such orbital shuttle relays, since the Escort Fighter is capable of docking with arrays of Boxes (themselves linked together) to provide the necessary fine tuning of inertial trajectories and station keeping while orbital transfer operations are ongoing in order to prevent excessive drift and/or mitigate the dangers of on-orbit collisions between arrays of Boxes during multiple orbital transfer runs. The Escort Fighter is also designed to assist with the necessary marshaling and movement of Boxes around the starship for both internal and external loading, after arriving on orbit (usually from a jump point) or prior to breaking orbit (for a jump point or other in-system transfer orbit trajectory).

As was done in previous iterations, the twin drive bays will lie port/starboard between the centerline hangar bay and the port/starboard docking points fore/aft on the wings.

Going to want to work out "alternate drive bay" arrangements, such that I can drop C/C/C or E/E/E drive bays into the available requisite spaces around the hangar bay. One of those "measure twice, cut once" kinds of deal, so I don't have to completely redesign EVERYTHING when moving from TL=9 to TL=10 and will be able to reuse MOST of the work I'll be doing with the TL=9 design ... even though I will have to redraw everything outside the hangar bay contents, because TL=9 means Composite Laminate bulkhead thickness (8 pixels wide) and TL=10 means Crystaliron bulkhead thickness (4 pixels wide). Point being that even if a redraw of all starship components is necessary, I won't need to to a complete layout rework of "where everything goes" when moving from TL=9 with C/C/C drives to a TL=10 with E/E/E drives when doing up the deck plans.



Also, at some point I'm going to have to design the (new) 16 ton Escort Fighter to fit into the 16 ton Box form factor (for reasons of interchangeability).

Be nice to see what that looks like.

Also, since the Escort Fighter is intended to have a pilot/gunner Crew=1 ... instead of a pilot, gunner Crew=2 arrangement ... I'm thinking I'd like to use a different shape of bridge than the one I've been working with during the last several iterations. Thinking I'd like to use Bridge 007 out of Geomorphs this time (which I'll need to resize for the scale I'm working at, obviously).

 

[Spinward Flow]

Next step with the deck plan is to implement the Hangar Services into the walls of the hangar bay (upper deck + main deck). Getting that done then helps define the boundaries that the drive bays will need to be fit into in the port and starboard wings.



So among other things, I needed to work out how the transverse access corridor connects to the wing mounted docking ports.

In previous iterations, I just had the transverse access corridor stretch to a single port/starboard grav lift docking points and then stop. This meant that the grav lift was the furthest forward/furthest outboard point in the deck plan nearest the leading edge of the wings, helping to define where the leading edge of the wing could be placed on the deck plans.

In this iteration, the grav lift docking points are closer to mid-wing rather than near the leading edge. This means that I don't need to have a "hard corner" in the deck plan up near the leading edge of the wing like I did previously. So this time, I decided to create a rounded curve in the access corridor to the 2 grav lift docking points in the port and starboard wings ... which I honestly think looks a bit better than the hard right angles I was limiting myself to in the previous iterations of deck plans.



Another point was that I wanted to change the shape of the robotic arm "slots" in the walls of the hangar bay(s).

In previous iterations, this was essentially a trapezoidal "bump" outwards in the hangar bay walls, which then created a somewhat "unwieldy" appearance for the robotic arms that were needed to guide boxes to their hold down points inside the hangar bay.

In this iteration, I moved to a more custom design implementation, which would avoid "bounding around windows" of the Stateroom Boxes and which would have (more obviously) easier access to the corner attachment points of the Boxes loaded into the double deck hangar bay. What I wound up with were essentially triangular "bumps" outwards in the hangar bay walls, rather than trapezoids like I had been working with previously.

Also, because of the change in armor material to Composite Laminates (and a corresponding increase in bulkhead thickness), I needed to redo the distributed Collapsible Fuel Tanks arrangement integrated into the (now 97 tons) "standard" hangar bay deck plan arrangement for all of this. The net result is that each Box location within the hangar bay gets two ~8 ton Collapsible Fuel Tank storage points to port/starboard. The idea is that if empty Cargo or Environment Boxes are loaded into the hangar bay, the port/starboard side hatches can be opened on those Boxes and the Collapsible Fuel Tanks can balloon into the empty Cargo or Environment Boxes with additional fuel, extending range (interplanetary or extra jumps) when appropriate and/or called for.

---

So when I'm talking about what the previous iteration looked like for these details, I'm referring to THIS:

Notice how the robotic arms are in trapezoidal bumps along the hangar bay walls?
Also, the collapsible fuel tank storage points are asymmetrically located ... as are the robotic arms. The reason for why that was done had to do with the 20 ton Box modular standard that I was working with back then. It makes more sense when you can see the two decks of hangar bays stacked with the Cargo Box located aft on the upper deck.

As you can see, the positioning of the collapsible fuel tank storage points were set to match up with the port/starboard manual hatch locations on the Cargo/Environmental Boxes.

You can also see that the previous iteration featured a hangar bay designed to accommodate 2 decks of 4x 20 ton Boxes, with one of those 20 ton Box form factor "slots" being occupied by the (previous) Escort Fighter design (TL=10 with a Model/4 computer) inside the hangar bay.

---

Now compare all of that legacy design work with what I'm doing now using a 6x 16 ton Boxes in a 97 ton hangar bay form factor in a TL=9 starship design.

I needed to get the main deck hangar bay features dialed in so that I would be able to copy those features into the upper deck of the hangar bay (shown above) where the Environment Box (forward) and the two Cargo Boxes (mid, aft) that sit above the Stateroom/Laboratory/Stateroom Boxes on the main deck.

Overall, I'm rather pleased with how all of this is developing up to this point.

Fun facts about the port/starboard drive bays and their respective sizing.

• The 236 ton TL=9 starship has C/C/C drives installed that deliver J2/2G/PP2 performance with up to 64 tons docked externally (with the 16 ton Escort Fighter being a part of that docking capacity allowance).
  • C/C/C drives = 20+5+10 = 35 tons
  • 35*14/3/1.5/1.5 = 72.6 deck squares
    • 72/2 = 36 deck squares per drive bay (port/starboard)
    • 18 long x 2 wide = 36 deck squares for drive bays to port/starboard of the central hangar bay
• The 310 ton TL=10 starship has E/E/E drives installed that deliver J3/3G/PP3 performance with up to 26 tons docked externally (with the 16 ton Escort Fighter being a part of that docking capacity allowance).
  • E/E/E drives = 30+9+16 = 55 tons
  • 55*14/3/1.5/1.5 = 114.07 deck squares
    • 114/2 = 57 deck squares per drive bay (port/starboard)
    • 19 long x 3 wide = 57 deck squares for drive bays to port/starboard of the central hangar bay

So it looks like I'm going to be doing drive bays that that are almost equally as long (18 vs 19 deck squares), with the primary difference being that the more powerful engines go into "wider" drive bays (2 vs 3 deck squares). However, the distance from the transverse access corridor to the aft end of the hangar bay is ~23 deck squares of distance. So the 16-17 deck squares aft of the transverse corridor point is right around the aft robotic arm "triangle bumps" in the hangar bay walls.



I'm also thinking of moving the 5 ton Cargo Hold to the starboard wing aft of the second grav lift, and balance it (somehow) with the 9 ton TL=9 Fuel Purification Plant in the port wing aft of the second grav lift. This is why I left the aft iris valves in the enclosures around those grav lifts, in order to have access to these features outboard of the drive bays towards the aft ends of the wings, rather than putting them forward up around the leading edge and near the bridge on this iteration.

 

[Spinward Flow]

Overall, I'm rather pleased with how all of this is developing up to this point.

Still quite pleased, now that I was able to work out the "engineering machinery" layout for the TL=9 C/C/C drives J2/2G/PP2 version.
Took quite a few hours to get it all figured out, but I'm really liking the results so far ... enough so that I'm honestly contemplating KEEPING the (thicker) Composite Laminate hull material bulkheads for the TL=10 E/E/E drives J3/3G/PP3 follow on version as well. My rationale for that choice is that the class is intended to be (substantially, if not completely/entirely) Civilian Grade construction. Additionally, the class is intended to "go out into the wilds" and economic backwaters to ply their trade in the low end of interstellar markets. That means needing to be able to find support (industrial, technological, etc.) at the VERY low end of interstellar tech levels in order to be able to source parts and spares from as wide a variety of locations as possible. Yes, Crystaliron becomes "available" as a hull material at TL=10, but if your starship gets disabled and needs repairs somewhere "out in the boonies" it's going to be "easier" to obtain Composite Laminate replacement materials (TL=7-9) than it will be to obtain Crystaliron replacement materials (TL=10-11) ... and that's not even counting the potential issue of Military versus Civilian restrictions that could potentially be a problem, in addition to sources and tracing if needing to remain a step ahead of the competition (or adversaries).

In other words, while Crystaliron is essentially a "wonder material" at TL=10, it could potentially come with "strings attached" for starship operators who would prefer NOT to leave too much of a logistics tail behind them (if they don't have to) which could become a liability, rather than an asset, under challenging circumstances. By contrast, at TL=9 Composite Laminates ought to be effectively "old hat" and relatively obtainable (with few questions asked, if push comes to shove). As a hull material choice, it broadens the possibilities for ease of repairs and is correspondingly "less suspicious" to obtain and maintain along the fringes of settled space.

Anyway, here's the latest update to the aft end of the main deck ... now with the C/C/C drive bays added in.

Think I'll do the 5 ton Cargo Hold as basically a 2.5x4 deck squares Grav Lift floored pressure compartment ... sort of like a glorified freight elevator large enough to park an air/raft in. That way the deck of the Cargo Hold can be lowered to the surface for loading/unloading of the platform, or can be raised to the dorsal of the wing for the launching and recovery of an air/raft berthed in that space.

Yeah, that'll play.
I'll just need to find the right Geomorphs icon to adjust into the necessary graphical element for the form factor I'll be using.

 

[Spinward Flow]

Think I'll do the 5 ton Cargo Hold as basically a 2.5x4 deck squares Grav Lift floored pressure compartment ... sort of like a glorified freight elevator large enough to park an air/raft in. That way the deck of the Cargo Hold can be lowered to the surface for loading/unloading of the platform, or can be raised to the dorsal of the wing for the launching and recovery of an air/raft berthed in that space.

Even worked out the fuel purification plant system(s) in a way that maintains some semblance of bilateral symmetry.

 

[Spinward Flow]

Well I wasn't expecting THAT to happen ...

---

All of my previous spreadsheet (in the naval architect's office) analyses of J3 Clipper designs have been "limited" to only J2+3 performance when double jumping. I could never figure out a way to reach for J3+3 performance while still having an "acceptable" remainder of revenue tonnage fraction that would keep the design economically viable (the compromises to achieve that result were just way too steep). The ... balance point ... just "never aligned" in a way that allowed everything to "fit" together neatly/nicely.

But I think I've actually "cracked" that issue now, but it took a bit of insight in order to achieve it ... which also meant shifting some boundaries on expectations in order to get everything to "settle into place" properly.

The first thing that I was noticing when moving from J2 (@ 236 tons) to J3 (@ 310 tons) and then notionally trying to extend all the way out to J4 (@ 460 tons) was that there was a "curious symmetry" building up in the details.

• J2 = C/C/C drives @ 236 tons (64 tons external capacity unused)
• J3 = E/E/E drives @ 310 tons (23 tons external capacity unused)
• J4 = K/K/K drives @ 460 tons (40 tons external capacity unused)

What made this progression so interesting was the code: 1 drive performance limits:

• Drive-C = code: 1 @ 600 tons ... code: 2 @ 300 tons
• Drive-E = code: 1 @ 1000 tons ... code: 3 @ 333 tons
• Drive-K = code: 1 @ 2000 tons ... code: 4 @ 500 tons

In other words, ~2x the drive power = +1 Jump number in slightly larger hulls.



That C/C/C drive mix really hits multiple sweet spots in the design sequence. It's 35 tons of drives, so only 1 Engineer crew position is required. The 236 ton form factor those drives can be installed into leaves 64 tons of external load capacity available, which in turn makes it possible to achieve J2+2 performance with a Collapsible Fuel Tank.

• J2 @ 300 combined tons = 60 tons fuel consumption
• J2 @ 252 tons = 50.4 tons fuel consumption

In other words, moving 3*16=48 tons of Boxes (Environment, Cargo, Cargo) plus the 16 ton Escort Fighter to the starship's exterior, that frees up 48 tons of internal hangar bay volume to be filled by the Collapsible Fuel Tank.

• 68 tons internal fuel tank + 48 tons collapsible fuel tank = 116 tons combined fuel capacity
• 68+48-60-50.4 = 5.6 tons fuel remaining after J2+2

So after the second jump, the starship would be "motivated" to maneuver to refuel, but at a consumption rate of 2.266 tons of power plant fuel per week under EP=6 maneuvering power, or 0.166 tons of power plant fuel per week under EP=0 "housekeeping" load only during jumps, there would be ~16 days of maneuvering reserve fuel outside of jumps after breakout following the second J2, 4 parsecs away from the point of origin. Absent a "combat damage" result, this ought to be sufficient maneuver endurance reserve to be able to refuel safely under most circumstances.



The E/E/E drive mix can achieve J2+3, but cannot stretch to J3+3 without seriously compromising some design fundamentals that I wasn't willing to budge on.

But then I thought about the possibility of an F/F/F drive mix instead ... ran the numbers ... and got a satisfying result after shifting a few things around a bit.

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Rule of Man Clipper
320 tons starship hull, configuration: 1
65 tons for LBB2.81 standard F/F/F drives (codes: 3/3/3, TL=10)
126 tons of total fuel: 320 tons @ J3 = 96 tons jump fuel + 30 tons power plant fuel
8 tons for TL=10 fuel purification plant (200 ton capacity is minimum)
20 tons for bridge
2 tons for model/2bis computer
97 tons for hangar berthing capacity

1. Escort Fighter = 16 tons
2. Environmental Box = 16 tons
3. Cargo Box = 16 tons
4. Stateroom Box = 16 tons
5. Laboratory Box (Type V-c regenerative biome life support) = 16 tons
6. Stateroom Box = 16 tons

• 97 tons capacity Collapsible Fuel Tank = 0.97 tons

* External Docking: 880 tons capacity
2 tons for Cargo Hold

= 65+126+8+20+2+97+2 = 320 tons

Crew = 5

1. Pilot-2/Navigator-2
2. Ship's Boat-2/Gunner-2
3. Engineer-2/Engineer-2
4. Steward-1/Steward-1
5. Medic-3

Revenue Tonnage @ J3

• 3x high passengers
• 16 tons environmentally controlled cargo
• 16 tons standard cargo
• 5*16 = 80 tons flex cargo capacity in hangar bay (when 5x 16 ton Box form factors are docked externally)

Drive Performances with External Loading

• 320 + 1.0*5*16 = 400 tons = J3/3G/PP3
• 320 + 1.0*17*16 = 592 tons = J2/2G/PP2
• 320 + 1.1*50*16 = 1200 tons = J1/1G/PP1
• 320 + 1.1*100 + 1.0*10*16 = 590 tons = J2/2G/PP2
• 320 + 1.1*200 + 1.0*3*16 = 588 tons = J2/2G/PP2
• 320 + 1.1*200 + 1.1*37*16 = 1191.2 ≈ 1192 tons = J1/1G/PP1
• 320 + 1.1*300 + 1.1*31*16 = 1195.6 ≈ 1196 tons = J1/1G/PP1
• 320 + 1.1*320 + 1.1*30*16 = 1200 tons = J1/1G/PP1
• 320 + 1.1*320 + 1.1*320 + 1.1*10*16 = 1200 tons = J1/1G/PP1
• 320 + 1.1*400 + 1.1*25*16 = 1200 tons = J1/1G/PP1
• 320 + 1.1*500 + 1.1*18*16 = 1186.8 ≈ 1187 tons = J1/1G/PP1
• 320 + 1.1*600 + 1.1*12*16 = 1191.2 ≈ 1192 tons = J1/1G/PP1
• 320 + 1.1*700 + 1.1*6*16 = 1195.6 ≈ 1196 tons = J1/1G/PP1
• 320 + 1.1*800 + 1.1*0*16 = 1200 tons = J1/1G/PP1

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The way the J3+3 fuel load would work is that 5x Box form factors get moved (by the Escort Fighter) to the exterior of the 320 ton starship.

• F/F/F drives are code: 3 up to 400 combined tons.
• 320 ton starship + 5*16=80 tons of Boxes = 400 tons = J3/3G/PP3

That opens up 80 tons of unoccupied volume in the internal hangar bay.

Leave the Cargo Box inside the internal hangar bay, but leave the Cargo Box empty so it can be filled with collapsible fuel tank fuel capacity, rather than carrying cargo (for ticket revenues). That then permits 97 tons of fuel to be loaded into the internal hangar bay (with 1x Cargo Box kept internal, filled with fuel).

The other 4x Boxes plus Escort Fighter are moved to dock externally with the hull.
A 320 ton starship with LBB2.81 F/F/F drives with codes: 3/3/3 has a design requirement of 96 tons for jump fuel and 30 tons for power plant fuel, for a combined 126 tons of integral main tank fuel capacity in the starship.

• J3 @ 400 combined tons = 120 tons fuel consumption (integral main fuel tanks are 126 tons, so this works)

Following the first J3, the 97 tons of collapsible tank fuel is pumped (over 3 hours, LBB A5, p13) into the integral main fuel tanks during the 16 hours of routine drive maintenance following breakout from jump. During those 16 hours of routine drive maintenance, all 5x Box form factors get moved (by the Escort Fighter) from the exterior of the starship into the internal hangar bay in preparation for the next jump.

• J3 @ 320 combined tons = 96 tons fuel consumption

The combined fuel load of 126 tons (main tanks) plus 97 tons (collapsible) yields a total fuel load aboard prior to departure of 126+97=223 tons.

• 223 - 120 - 96 = 7 tons of power plant fuel endurance remainder during J3+3 transit

Housekeeping power (EP=0) fuel demand will be (320+16*5)/2000=0.2 tons of fuel consumption per week.
Maneuvering power (EP=12) fuel demand will be 12*0.35=4.2 tons per week.

Fortunately, model/2bis computers consume EP=0, or that housekeeping fuel demand would be higher (0.55 tons of fuel per week to sustain the EP=1 demand of a model/3 computer plus housekeeping load).

In other words, after 2 weeks in jump (consuming 0.4 tons for housekeeping power), ~10 days of maneuver endurance will remain upon arrival at the destination after a J3+3 transit across 6 parsecs.

Revenue tonnage for the voyage would be "minimal" ... at 3 high passengers and 16 tons of environmentally controlled cargo ... but if you REALLY NEED to transit 6 parsecs as quickly as possible with a high value "precious" cargo ... you can do it with this redesign.



The other thing that "popped out of the math" with this redesign is:

• 310 ton E/E/E drive version can move 3x high passengers and 37 tons of cargo @ 1J3
• 320 ton F/F/F drive version can move 3x high passengers and 114 tons of cargo @ 1J3

Needless to say, THAT kind of a "performance bump" was unexpected and totally justifies dropping the E/E/E drives configuration for the more powerful/capable F/F/F drives alternative.

And just for funzies ... as detailed above, the 320 ton F/F/F drives design can externally tow up to 800 tons of Big Craft @ J1.

Deal ... sealed ... on the J3 design.
It loses the 5 ton cargo hold which can be repurposed as a Mail Vault or a Vehicle Berth ... but that's a SMALL PRICE TO PAY for being able to enable J3+3 fuel endurance and the ability to externally tow up to 800 tons of Big Craft, without needing to increase the number of crew positions required to crew the starship!