CT Only: MCr 28 for a Modular Cutter

[atpollard]

I can't imagine that this hasn't been discussed to death, but has anyone ever been able to figure out how they came up with the MCr 28 price tag for only 20 dTons of cutter without its custom module. I tried plugging the known prices from LBB 2 (like hull, MD-A, PP-A) and could get pretty close with tonnage (looks like about a 10 dTon bridge) but nowhere near the official MCr 28 price tag.

Then I took a look at Book 5: High Guard and the 'official' rules for designing small craft and my first pass still didn't come close to MCr 28 for a Modular Cutter (without the module). This was not a big surprise, LBB2 vs HG compatibility issues are hardly news to anyone. I was a bit disappointed to discover that there was nothing in the errata on Small Craft prices, so those prices are still thought to be 'correct'.

I have some basic issues when 20 dTons of a 50 dTon Cutter costs more than an entire 100 dTon Scout that appears to use the same drives, far more hull, and adds a jump drive, but I am willing to give the numbers a chance to speak for themselves. So far, they are talking gibberish.

Just for laughs, I looked up the 50 dTon Modular Cutter in Mongoose Traveller Core Rules ... It still costs MCr 28 plus the cost of the module. I have no idea how the pricing works out under MgT Small Craft design, and my focus at the moment is on Classic Traveller. I just found it interesting that the price remained across the jump to a new edition.

So does anyone have a design breakdown for a 50 dTon Modular Cutter that adds up to MCr 28?

[As an aside, the T5 Modular Cutter design posted on COTI was interesting ... and far less than MCr 28.]

 

[Matt123]

FWIW, this is what I worked out a few months ago.

Cutter, modular, Cutter Auxiliary
50 ton, TL 9 Civilian Design, 28.30 MCr
1 crew (Command: 1+0)

_Ton.____MCr.____EP.____
| __.__ | _5.50 | _.__ | Cone, streamlined, fuel scoops
| _1.00 | _0.05 | _.__ | 2 x control couches, no bridge
| _1.00 | _2.00 | _.__ | computer model 1, rated as model 0 (no bridge)
| _5.50 | _2.75 | _.__ | drive maneouver #4
| _6.00 | 18.00 | _.__ | power plant #4
| __.__ | __.__ | 2.00 | agility #4
| _2.00 | __.__ | _.__ | fuel, PP endurance 4 weeks (16 weeks powered down)
| _1.00 | __.__ | _.__ | weapon mounts and fire control
| 30.00 | __.__ | _.__ | cutter module, berth
| _3.00 | __.__ | _.__ | 1 ton reserved computer space3 ton
‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒
| 49.50 | 28.30 | 2.00 EP used, PP generates 2.00 EPs

28.58 MCr (first ship, includes architect fees) built in 24 weeks
22.64 MCr (20% discount in volume, TCS) built in 20 weeks
CT Ship Designer by Matt. Visit https://tca-2014-12.herokuapp.com

And these are the notes I made at the time on the differences.

Cutter, modular (50 ton)
Book 2 (1981, p18), The Traveller Book (1982, p63)

Differences:
• Hull: streamlined, cone.
• No bridge: means the computer is rated one level lower.
• Reserved computer space: 3 ton, allows for upgrade to model 4.
• Unused space 0.5 ton (may purchase crew couch or use for light cargo)
• cost: 25.47 MCr (CT Ship Designer, no weapons, 10% discount for standard design)
• cost: 28.00 MCr (Book 2, The Traveller Book).

Variants [1]:
• computer: #1 -> TL 9, agility 0 with two lasers else agility 4, cost 25.47 MCr (no weapons, 10% discount for standard design)
• computer: #2 -> TL 9, agility 0 with two lasers else agility 4, cost 31.77 MCr (no weapons, 10% discount for standard design)
• computer: #3 -> TL 9, agility 0 with one laser else agility 4, no second laser, cost 39.87 MCr (no weapons, 10% discount for standard design)
• computer: #4 -> TL 10, agility 0, no lasers, cost 50.67 MCr (no weapons, 10% discount for standard design)

[1] The Traveller Book details four Cutter variants with computer models 1-4.
v110515

I found across several book 2 designs that the biggest difference was official descriptions not including a 10% discount for a standard design. The same analysis on the Shuttle came out at 37.55MCr (after 10% discount) versus the 33MCr published price. Meaning the Shuttle is more incorrect than the Cutter . Happy to post that as well if you are interested.

Feedback welcome on this interpretation and I'm especially interested in any CT sources I have missed that have offered prices or stats on the Cutter (got Book 2 and The Traveller Book). Cheers.

 

[Matt123]

Oops, you were comparing it with the Scout, not the Shuttle.

The Scout hull is cheaper by 2.5MCr by virtue of being a standard hull. Small craft all use custom hulls. This accounts for a large part of its relative cost and soaks up much of the increase in cost, for example, with drives (~1.25MCr) and computer (~2MCr).

 

[TNE2300]

JTAS #5 (1980)
has an article for the LSP Modular Cutter

"Base price is MCr9.25, excluding modules."

it is listed as having 15 dtons fuel
so looks like it is still a LBB2/77 design
the original cutter was not modular

 

[Matt123]

JTAS #5 (1980)
has an article for the LSP Modular Cutter

"Base price is MCr9.25, excluding modules."

it is listed as having 15 dtons fuel
so looks like it is still a LBB2/77 design
the original cutter was not modular

Well spotted, it'll take some interesting mental gymnastics to replicate this version . 15 dtons fuel is mentioned at least twice in the article, so it seems pretty deliberate. However at one point it claims the cutter without a module is 30dton which only leaves room for 20dton modules. Yet the fuel module carries 26dton and the cargo module 24dton.

After some experimentation, the killers price wise are the pp4 and the price of the custom hull. The 15dton of fuel while a little OTT, doesn't impact the price, but I wouldn't hesitate to reduce it for engineering space. My best effort drops maneouver down to 2G and crew to 1 and it still costs 11.05MCr after discount. So not very close...

JTAS #5 was published in 1980, well after book 2 in 1977. I'm not aware the price changed between the 1977 and 1981 printings. Any other ideas anyone?

 

[TNE2300]

JTAS #8 (1981) and Adv #7 Broadsword (1982)

"The cutter has a four ton bridge installed
and mounts a Model/1 computer.
It is armed with a single missile rack."

per JTAS8
"Total craft cost, less module: MCr30.75"
per Adv7
"Total craft cost, less module: MCr31.5"
but shows 30.75 under HG stats

per High Guard the 4 dton bridge is an error
4 dton is the minimum size allowed
small craft bridges are 20% of craft tonnage
so should be 10 dtons

also note
fuel is now 2 dtons not 15
I do not see a reference to a small craft bridge in LBB2/81
don't see a small craft bridge tonnage requirement in TTB

 

[boomslang]

I can't imagine that this hasn't been discussed to death, but has anyone ever been able to figure out how they came up with the MCr 28 price tag for only 20 dTons of cutter without its custom module. I tried plugging the known prices from LBB 2 (like hull, MD-A, PP-A) and could get pretty close with tonnage (looks like about a 10 dTon bridge) but nowhere near the official MCr 28 price tag.

I once half-seriously considered that the spinal brace linking the Cutter's command pod to its drive pod must be made of precious, tempered Unobtanium or something; it is simply too spindly looking to convince me that ordinary TL9 materials technology could handle the 6G loads expected of it when a Module is not present.

 

[whulorigan]

I once half-seriously considered that the spinal brace linking the Cutter's command pod to its drive pod must be made of precious, tempered Unobtanium or something; it is simply too spindly looking to convince me that ordinary TL9 materials technology could handle the 6G loads expected of it when a Module is not present.

I seem to have the vague recollection in the back of my head that when a module is not loaded, the Cutter is limited to 2g.

 

[Travellerspud]

I seem to have the vague recollection in the back of my head that when a module is not loaded, the Cutter is limited to 2g.

You may be thinking of the GURPS Modular Cutter version, which has various G-limits depending on which module you have loaded (and no module was 2g IIRC)

 

[atpollard]

I thought that it looked pretty skinny as well, so I ran some rough structural calculations on it. It helps that most of the mass is together in the rear and the cockpit is pretty light. My back of the envelope calculations show that a 1 meter spine should span a 20 meter gap with even TL 4 steel and 6G loading.

I suspect that having the support so far off axis of the thrust will make it a rather 'bouncy' craft, but it should support the load without shearing, bending or buckling. (At least to a first order approximation).

 

[Matt123]

JTAS #8 (1981) and Adv #7 Broadsword (1982)...

Ta for those. I just whiled away a couple of hours looking for others and found a few more. My notes have expanded somewhat.

Cutter, modular (50 ton)
JTAS #5 (1980, p6)[1] , Traders and Gunboats (1980, p41), Book 2 (1981, p18), JTAS #8 (1981, p26), The Traveller Book (1982, p63), Adv 7 Broadsword (1982, p19), Spinward Marches Campaign (1985, p35), Challange 25 (1985?, p8)

Differences:
• Hull: streamlined, cone.
• No bridge: means the computer is rated one level lower. [2]
• Reserved computer space: 3 ton, allows for upgrade to model 4.
• Unused space 0.5 ton (may purchase crew couch or use for light cargo)
• cost: 25.47 MCr (CT Ship Designer, no weapons, 10% discount for standard design)
• cost: 28.00 MCr (Traders and Gunboats [3], Book 2, The Traveller Book).
• cost: 30.25 MCr (Spinward Marches Campaign, Challange 25 [4])
• cost 30.75 MCr (JTAS #8, Broadsword prices 30.75MCr and 31.5MCr, both sources include a single missile rack, note bridge size used is illegal [2])

Variants [5]:
• computer: #1 -> TL 9, agility 0 with two lasers else agility 4, cost 25.47 MCr (no weapons, 10% discount for standard design)
• computer: #2 -> TL 9, agility 0 with two lasers else agility 4, cost 31.77 MCr (no weapons, 10% discount for standard design)
• computer: #3 -> TL 9, agility 0 with one laser else agility 4, no second laser, cost 39.87 MCr (no weapons, 10% discount for standard design)
• computer: #4 -> TL 10, agility 0, no lasers, cost 50.67 MCr (no weapons, 10% discount for standard design)

Extra information:
• Without modules it's 4G acceleration is increased to 6G, for limited periods (JTAS #5 p6, JTAS #8 p26, Broadsword p19)
• Second hand Cutters in poor condition may be available ~25% of original cost (JTAS #5 p6, note concerns [1])

30ton Modules:
• ATV cradle. 1.2MCr, excluding ATV (JTAS #5 p6)
• ATV cradle. 1.8MCr, including ATV (Book 2 p18, The Traveller Book p63, JTAS #8 p26, Broadsword p19 [6])
• Personal transport (x60). 2.0MCr (JTAS #8 p26, Broadsword p19)
• Passenger and Cargo module (24 passengers or 24 tons of cargo). 3.0MCr (JTAS #5 p6)
• Cargo transport (25 tons plus 10 passenger seats) 1.0MCr (JTAS #8 p26, Broadsword p19)
• Open module (30 ton customisable). 2MCr. (Book 2 p18, The Traveller Book p63)
• Fuel Skimmer (30, 26, 28 tons fuel). 1.0MCr (Book 2 p18 30ton, The Traveller Book p63 30ton, JTAS #5 p6 26ton, JTAS #8 p26 28ton)
• Assault boat (16 troops). 2.5MCr (JTAS #5 p6, JTAS #8 p26, Broadsword p19)
• Pressurized shelter (8 persons at double occupancy. Surface, orbit or ship. Endurance: months). 4.5MCr (JTAS #5 p6, JTAS #8 p26, Broadsword p19)
• Weapons module (orbital, independent, missile or dual beam laser, life support 4 crew). 7.2MCr (JTAS #5 p6)[7]
• Weapons module (orbital, independent, triple beam laser). 8.0MCr (JTAS #8 p26, Broadsword p19)[7]
• Fighter frame (four 6ton fighters). 2.0MCr (JTAS #8 p26, Broadsword p19)
• Zero-G mining module (2 persons). 3.5MCr (JTAS #5 p6)

[1] The JTAS #5 design is deeply flawed, claiming similar specifications as later books, plus carrying 15tons of fuel (+13ton) and costing around a third of the price at 9.25MCr. Note that if acceleration is dropped to 1G, 15ton fuel can be carried and cost can be reduced to 12.2MCr after discount.
[2] JTAS #8 states a 4ton bridge is present, while HG (p34) requires a 10ton bridge, 20% of the ships design tonnage.
[3] Traders and Gunboats includes a bridge, but no computer per it's HG USP (p47). See note [2].
[4] Mineral Class, TL 9, includes triple missile rack plus module allowing 12 passengers, 15ton cargo, 13.5ton fuel --- this might utilise the spare 0.5ton in the cutter
[5] The Traveller Book details four Cutter variants with computer models 1-4.
[6] Broadsword specifies wheeled ATV only.
[7] Weapons module likely warrants an independent design requiring PP, computer 1, accommodation, fuel and turret.
v291115

After all that, I made no changes to the version I created. It seems to capture the role ok and allows for computer and weapons upgrades to make it reasonable competent in combat.

The 4ton bridge might be a hang-over from 1st edition rules (which I don't have, must update my CDs...), while the weapons module I thought also strictly speaking, breaks the design in a way much more subtly than does the famous Gazelle. I like the weapons module but I would treat it as a carried craft, meaning it cannot fire while mounted.

As before, very interested in comments, stuff I missed.