CT Only: Spinward X-Courier

[Spinward Flow]

Spinward X-Courier
:alpha: TL=11 (LBB5.80)
Ship Type: XF (Express, Fast)

Tonnage: 194 (custom hull)
Configuration: 6 (Streamlined, 15.52 MCr)
Fuel Scoops (MCr 0.194)
Armor: 0

Jump-2 (5.82 tons, MCr 23.28, Capacitor storage: 69.84 EP maximum)
Maneuver-5 (27.16 tons, MCr 13.58, Agility: 5 requires 9.7 EP)
Power Plant-5 (29.1 tons, MCr 87.3, EP: 9.7)
Fuel: 48.5 tons (2 parsecs = 38.8 tons, 4 weeks operations = 9.7 tons, up to 24 weeks powered down)
Fuel Purification Plant: 200 ton fuel capacity (7 tons, MCr 0.034) (LBB5.80, p27, 36)

Dual Turret (1 ton)
Missile Rack: 1 (Code: 1, Battery: 1, MCr 0.75)
Sandcaster: 1 (Code: 3, Battery: 1, MCr 0.25)
Bridge (20 tons, MCr 0.97)
Computer: 2 (Code: 2, 2 ton, MCr 9, TL: 7, EP: 0)

Crew: 2 (Pilot, Gunner)
Staterooms: 2 (8 tons, MCr 1)
Cargo: 45 tons (5 ton Mail Vault, 40 tons internal cargo remaining)
Collapsible Fuel Tank: 40 ton capacity (0.4 tons, MCr 0.02)
Waste Space: 0.02 tons

Spinward X-Courier   XF-1626621-030000-00001-0   MCr 121.5184  194 tons
    batt bearing                   1         1                   TL=11.
    batteries                      1         1                  Crew=2.
Passengers=0 (1 possible). Cargo=45. Fuel=48.5. EP=9.7. Agility=5. FPP.
Jump-1, Maneuver-4 with 0.1-52.9 tons external cargo added.
Jump-1, Maneuver-3 with 53-97 tons external cargo added.
Jump-0, Maneuver-3 with 97.1-145.5 tons external cargo added.
Jump-0, Maneuver-2 with 145.6-349.2 tons external cargo added.
Jump-0, Maneuver-1 with 349.3-1164 tons external cargo added.

Interplanetary Travel (distance, acceleration, time) (link)



Total Cost (first in class): MCr 151.898
20% Down Payment (first in class): MCr 30.3796
Architect Fees (first in class): MCr 1.51898
Construction Time (first in class): 47 weeks
Annual Overhaul (first in class): Cr 151,898 (LBB2.81, p8)

Additional Ships Cost: MCr 121.5184
Additional Ships 20% Down Payment: MCr 24.30368
Additional Ships Construction Time: 38 weeks
Additional Ships Annual Overhaul: Cr 121,519 (LBB2.81, p8)



Bank Financing (1st ship): Cr 316,455 per 2 weeks for 50 weeks per year
Bank Financing (2nd+ ships): Cr 253,164 per 2 weeks for 50 weeks per year

Maintenance (1st ship): Cr 6076 per 2 weeks for 50 weeks per year
Maintenance (2nd+ ships): Cr 4861 per 2 weeks for 50 weeks per year

Life Support: Cr 4,000 per 2 weeks (LBB2.81, p7-8)
Crew Salaries: Cr 3640 per 2 weeks (including 2 weeks annual overhaul) (LBB2.81, p8, 11, 16, 23)

Berthing Costs: Cr 100 for 6 days, plus Cr 100 per day after 6 days (LBB2.81, p8)
Surface to Orbit Shuttle Costs: Cr 10 per cargo ton, Cr 20 to 120 per passenger (LBB2.81, p9)
Fuel: Cr 500 per ton (refined), Cr100 per ton (unrefined), Cr 0 (skimmed) (LBB2.81, p7)

Mail Delivery: Cr 25,000 revenue per delivery (LBB2.81, p9)
Interstellar Cargo Transport: Cr 1000 per ton (LBB2.81, p8-9)
Interplanetary Charters: Cr 1 per hour per ton of ship (Cr 194 per hour), minimum 12 hours (LBB2.81, p9)
Interstellar Charters (2 weeks): Cr 900 per ton of cargo, Cr 900 per low passage berth, Cr 9000 per high passage berth (LBB2.81, p9)
Subsidy reduces gross revenue receipts by 50% for passengers, cargo and mail (LBB2.81, p7)

 

[Spinward Flow]

Under the heading of ... well I wasn't expecting to see that happen ... o:

So last night as I was dropping off to sleep, I started wondering if it might be possible to "backwards compatible port" the Spinward Flex Courier from TL=13 back down to TL=11 (required for Jump-2) ... and if so, what would need to happen to the design (and what would those changes cost)?

Well ... here's the answer ... and once again, remarkably enough ... the solution winds up being a 194 ton hull, which is just bonkers.

The basic idea was to maintain the missile/sandcaster dual turret (1 ton), bridge (20 tons), model/2 computer (2 tons), 2 staterooms (8 tons), 45 tons of cargo space (5 tons of which become the x-mail strongroom, leaving 40 tons of cargo capacity) and a 40 ton collapsible fuel bladder that can fill the cargo bay (0.4 tons when empty). The starship would also need to have a fuel purification plant, but at the lower TL=11 it would require 7 tons instead of the 5 tons of the TL=13 version.

Total fixed tonnage = 83.4 tons (TL=11)
Total fixed tonnage = 81.4 tons (TL=13)

Since TL=9-12 power plants require 3 tons per EP instead of only 2 tons per EP like TL=13-14 power plants do, it was kind of obvious that a reduction in maneuver drive would be necessary in order to fit everything inside of the under 200 tons hull form factor.

However, the balancing factor for the TL=13 version was jump-2 (3%), maneuver-6 (17%), power plant-6 (12%), fuel (26%) added up to being 58% of the starship tonnage in aggregate.

For the TL=11 version, IF the maneuver drive and power plant were reduced by -1 you wind up with jump-2 (3%), maneuver-5 (14%), power plant-5 (15%), fuel (25%) adding up to being ... 57% of the starship tonnage in aggregate.

TL=11 ... 83.4 / (1-0.57) = 193.953488 tons (minimum)
TL=13 ... 81.4 / (1-0.58) = 193.809523 tons (minimum)

In other words, both the TL=11 and TL=13 versions basically wind up at exactly the same 194 tons of optimal hull size ... and the only performance difference between the two versions is that the TL=11 version has 5G maneuver instead of 6G maneuver, the missile rack does not get the TL=13 +1 modifier (so code: 1 instead of code: 2) ... and because power plants cost more per ton than maneuver drives do, the TL=11 version costs slightly more to purchase (MCr 121.5184 instead of MCr 109.8752 to purchase in volume production, an increase of MCr 11.6432).

This then suggests to me (as a Traveller universe world builder) that despite the fact that I (as a ship designer) came to this conclusion from the high tech level and worked my way backwards to achieve this result, in the "actual" Traveller universe the development cycle would no doubt have been the reverse ... the TL=11 version would have been the first to be put into production, with the TL=13 version then being a later refresh/upgrade to slightly improve performance (6G vs 5G maneuver, fuel purification, missile tech) over the "original" TL=11 version of the 194 ton Spinward X-Courier.

So ... slightly pricier (by MCr ~11.64) to buy, slightly reduced performance (5G instead of 6G) ... but no loss in cargo/x-mail capacity or even cargo/fuel flex capacity, while being 2 tech levels lower to manufacture and maintain, making the TL=11 version even more of a frontier/provincial starship with a wider variety of possible construction yards and opportunities for annual maintenance along preferred routes. Ironically, this might make the higher priced yet lower tech level version of the ship even more common along the fringes of Imperial space in the Spinward Marches due to the "relative ease of maintenance and support opportunities" a lower tech level design offers, opening up even more potential backwater systems and subsectors to increased x-mail and cargo traffic (looking at you, Five Sisters, Sword Worlds and District 268 subsectors!), helping to "bind" those backwater systems better into the interstellar commerce networks of their respective subsector and sector governmental authorities.



So ... yeah.
TL=11 @ J-2, 5G = 194 tons
TL=13 @ J-2, 6G = 194 tons

Boom.



And oh hey look, the TL=11 version is perfectly usable (probably under a different ship class name, such as perhaps the Fringe X-Courier in an example of convergent evolution in starship designs) in the Distant Fringe Traveller setting with its TL=12 and Jump-2 limits.

Distant Fringe Map

If anyone maintaining the travellerwiki pages for the Distant Fringe would like to work with me at the task of adding the TL=11 version to the Starships of the Distant Fringe, send me a PM and we can work together on adding this unique starship design to the resources available to the Distant Fringe setting.

 

[Spinward Flow]

perhaps the Fringe X-Courier

It's only AFTER writing the above that I started looking into the Distant Fringe as a setting ... and what do I find?

X-Range Starship

X-Range Starship: A designation applied to starships within the Distant Fringe region: vessels fitted with drop-tanks or collapsible fuel tanks in order to increase their operational range.

Starships are limited by the performance of DeVoss-type jump drives - the so-called Jump-2 Barrier.
Ships equipped with temporary additional fuel tankage are referred to as being "X-Range", an abbreviation for "Extended Range Vessels". Most classes of military scouts are designed this way.

I swear I was thinking in terms of x-mail (since that's kind of been my "thing" with my ship designs on these forums), rather than in terms of extended range, when thinking the ship class might be called the Fringe X-Courier if built out in the Distant Fringe setting o: ... but now that I know this bit of lore for the setting, the X-Range designation becomes even more fitting of a starship type name for a merchant/courier that can achieve 2 jump-2 (when needed) in order to link star systems together via x-mail deliveries.

Doing a cursory look around the Type A starports, although multiple worlds would be capable of producing the design ... I'm thinking that the most likely locations for the design to be in near continuous rollover production (replacing older ships that have worn out and needed to be scrapped) would be found at:

• Nexus / Sena / Halcyon
• Pador / Orret / Far Home
• Sudi Verisia / Aredian / Far Home

Funny how "the stars align" like this when you have trouble falling asleep at night because of an untapped possibility in a variation of an existing design you've made that just has to get out of your head and be shared somewhere like this. Somehow I started out in the Spinward Marches and wound up building something that not only "works" there, but also thousands of parsecs away in the Distant Fringe too.

Sometimes, you just can't help but make this stuff up ...