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MGT Only: 50 ton jump cutter (1e, variant rules)

Brandon C

SOC-13
Yes, this breaks one of the biggest rules of the Traveller universe. This is based on a ship I designed in the mid-80's, with the idea of jump torpedoes fresh on my mind. I will note, however, that to prevent the abuse of very small ships having J-drives. the minimum size for a J-drive is 2 tons (a J-1 drive in a 100-ton ship under CT HG rules). So, a 10-ton craft can mount a J-drive -- but it will take up 20% of the space available. Anyway, this is for my IMTU pocket empires campaign.;)

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50-ton jump cutter

This light starship is used to transport small but important cargoes or 1-3 passengers. In some ways, it is a smaller, cheaper and slower alternative to the 200-ton fast courier. It is used by the Navy and Scouts and is sometimes handed out to a favored member of either service when retiring (under the same conditions as the 100-ton scout/courier). The jump cutter was designed with the same dimensions as the 50-ton modular cutter, allowing it to use the same small craft bays.

The jump cutter has maneuver drive-sE, jump drive-2 and power plant-sG, giving Jump-2 and 2G acceleration. 11.5 tons of fuel supports the power plant for 2 weeks and one Jump-2. A fuel processor is installed. A Model 2 computer and basic military electronics are located in the two-man control cabin. There are 3 staterooms. The ship has one hardpoint, with a double turret holding a beam laser and missile rack (12 missiles). A compact air/raft is carried for general duties. One airlock is provided. Cargo capacity is 4.5 tons and there is a 0.15 ton (2 m^3) ship's locker. The ship is streamlined and has armor 2.

Some users replace the missile rack with a sandcaster and the beam laser with a pulse laser. This saves MCr 0.75 and the missile magazine is converted to the sandcaster magazine. Very rarely, a jump cutter is armed with a missile rack and sandcaster, with the powerplant downgraded to sE. Only six missiles and ten sand cannisters are carried the magazine. Extra ammunition must be stored in the cargo hold or in the space freed up in engineering by the smaller fusion reactor. This saves MCr 2 and 0.9 tons.

Navy and Scout characters who receive a ship's boat or scout ship as a mustering out benefit may take a jump shuttle instead. The cutter, if armed, will be outfitted with missile rack and sandcaster.

Crew consists of a Pilot, engineer, and gunner. If additional crew or passengers are carried, double-bunking is required. The ship costs MCr 21.635 with compact air/raft.
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Compact air/raft

This is a smaller version of the standard open air/raft where a largo cargo capacity is not required.

Taking up 10 m^3 (1 ton), it has a crew of one (river), carries 3 passengers and has 0.32 tons of cargo space. The hull provides 6 points of armor. It uses a fusion power plant with 168 hours of fuel. Electronics include advanced compact sensors and a 50 km laser comm. Top speed is 105 kph. Cost is Cr 272,000 and loaded weight is 2050 kg.
 
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The minimum jump fuel also should be based upon 100Td... so it's 10Td.
So, you lose 22 of 50 tons... 44%...
 
The minimum jump fuel also should be based upon 100Td... so it's 10Td.
So, you lose 22 of 50 tons... 44%...

No, I'm basing it on actual craft tonnage. You do raise a point I need to have a proper handwave for, though.

First thing that comes to mind is that, simply, jump drives under two tons just won't work -- no jump bubble is formed. Like all jump drives, though, it can function at a lower rating than designed.

My other choice is to use hyperdrives, which will break the setting even more.
 
Why the PP-4 if you are only carrying a single laser?

A pp sL should require 4 dT fuel for 4 weeks?

I cannot get the tonnage to add up, I get more like 60 dT of components?

Half a Jump drive A should be 5 dT or 7.5 dT?

If you actually consider taking it into combat a little Reinforced Hull might be in order? As is a stiff breeze will kill it...
 
Why the PP-4 if you are only carrying a single laser?

Originally it was capable of mounting two energy weapons. I dropped that to one and did change the spreadsheet. Must have missed revising the text.

pp sL should require 4 dT fuel for 4 weeks?

Make it two weeks..

I cannot get the tonnage to add up, I get more like 60 dT of components?

I used 0.5 tons for the air/raft, which is much closer to what the vehicle design supplement calls for than the rather excessive 4 tons.

a Jump drive A should be 5 dT or 7.5 dT?

Hmmm. Okay, this is a problem. MgT used the same flawed drive volumes and costs as CT Bk 2, which do not match CT HT formula results in any way, and it was the CT HG jump drive formula I was using. Thanks s, BTW, the only thing I really liked about HG: drive formulas instead of drive tables.
 
I used 0.5 tons for the air/raft, which is much closer to what the vehicle design supplement calls for than the rather excessive 4 tons.
Even a small hatchback like a VW Golf if bigger than that...

Still a few dT overweight?
I get the cost to about MCr 31 with a LBB5 2 dT jump drive à MCr 8?
 
Even a small hatchback like a VW Golf if bigger than that...

Still a few dT overweight?
I get the cost to about MCr 31 with a LBB5 2 dT jump drive à MCr 8?

4 tons is 3x3x6m or 9' 10" x 9' 10" x 19' 8". the air raft bay should be 3.1m or 10' 2"...
A standard 1 car garage is typically 14' x 10' x22 '... with a rough minimum of 12' x 8' x 20'

A typical midsize car is about 7' wide, including mirrors, 16' overall length, 4' 11" tall. (exemplar is a dodge avenger, width 72.8" + mirrors, which extend some 6" each past the window...)

Now, let's use guideline of 130% volume used for large craft...

Given the 4 Td, that's 14x4=56m³ ... 56/1.3 ≅ 43.1m³ roughly... now, finding the double-cube... 21.55m³ ... and cube rooting it... about 279cm.
So, roughly, with the canopy up and gear down, the A/R takes 2.78x2.78x5.78 m, some 44.7m³ with rounding - close enough. That's 11cm each side... 4.3"...

For what is, esssentially, the Humm-Vee of its era. If we want a more reasonable clearance - say, 1 foot - on each side, it becomes (3-0.61) x (3-0.61) x (6-.61) = 2.39 x 2.39 x 5.39 = 30.8m³ of vehicle... 7'10" x 7'10" x 17'8"...

The hummer, BTW, is 7.1' x 6' x 15' (2.16 x 1.83 x 4.57 m) - so we are in the ballpark. In other words, if you can get out the top, you can put a HMMWV in there.
 
Even a small hatchback like a VW Golf if bigger than that...

You're right. I should have glanced at Supplement 6: Military Vehicles before I estimated the air/raft volume (I couldn't find the spreadheet where I did designed an open air/raft). I need to raise it from 0.5 tons to 1 ton.

Ah, found the spreadsheet.. Okay, what I designed was a compact air/raft. It's speed was closer to the CT than MgT version, and carries a lot less cargo than the CT one. The compact air/raft is 10 m^3 (1 dton according to p.4 of Supplement 6). Driver, 3 passengers, 340 kg cargo, 105 kph, fuel for one week

I'll clarify that the cutter carries a compact air/raft, not a "truck"-sized one.

I get the cost to about MCr 31 with a LBB5 2 dT jump drive à MCr 8?

Yeah. My bad. I used the cost per ton from MgT 1e HT capital ship design, not from CT HG. I'm leaning on using the lower number since M-drives are much more expensive in MgT than CT

Here is a quick tonnage breakdown (with revised CA/R space)

Armor: 1.25
M-drive: 2.5
J-drive: 2
PP: 2
PP fuel: 2
Jump fuel: 10
Fuel processor: 1
Fire control/hardpoint: 1
Missile magazine: 1
Control cabin: 6
basic mil. electronics: 2
staterooms: 12
airlock: 1
CA/R: 1.1
Cargo: 5
Ship's locker: 0.15

total: 50
 
I recall doing up a semi-canon 50 dT jump cutter by borrowing the jump mesh from the jump ship in Supplement 9 - that net thing that it used to transport planetoid chunks and cargo & passenger pods. I postulated a cutter with a jump mesh grid that could be erected on spars, puffer-fish style, to fill it out to the 100 dT minimum required volume for jump. Used it as a kind of jump lifeboat so navy ships could send for help if they misjumped into deep space.
 
I used the cost per ton from MgT 1e HT capital ship design, not from CT HG. I'm leaning on using the lower number since M-drives are much more expensive in MgT than CT
Sounds reasonable.


Here is a quick tonnage breakdown (with revised CA/R space)

Armor: 1.25
M-drive: 2.5
J-drive: 2
PP: 2
PP fuel: 2
...
That explains my problem, I thought you used sH drives (as stated in the OP).
You are using sE drives?
 
That explains my problem, I thought you used sH drives (as stated in the OP).
You are using sE drives?

I changed them on the spreadsheet during the thread without updating my original post.

Maneuver drive is sE and popwerplant is sG (necessary if the craft is to have an energy weapon). I have updated the OP to reflect changes.
 
Just wrap the mesh around some externally installed fuel bladders, that inflate like waterwings.

Our Late Friend Hans had suggested something very similar to this as a way of keeping the jump torpedo canonical.

For the purposes of this design, I could treat the mesh as a solar sail, but with 10x the cost and it interferes with use of the maneuver drive, not jump drive.

(yes, this means that a ship deploying a jump mesh would have to come to a dead stop before, but I think this was standard routine in at least one Traveller edition for safety reasons)
 
Our Late Friend Hans had suggested something very similar to this as a way of keeping the jump torpedo canonical.

For the purposes of this design, I could treat the mesh as a solar sail, but with 10x the cost and it interferes with use of the maneuver drive, not jump drive.

(yes, this means that a ship deploying a jump mesh would have to come to a dead stop before, but I think this was standard routine in at least one Traveller edition for safety reasons)

Technically, since it won't be able to use the maneuver drive to maneuver out of the way of any flotsam that just happens to be near the point of emergence at the target world, it wants to make sure its velocity relative to any debris that might be orbiting at that point is zero.
 
It is still a house rule. Most editions of Traveller specifically does not allow that.

If you want spacecraft smaller than 100 dT to be able to jump, just house rule it...
 
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