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Type ST Transport Scout: 199Td, J4/2G (LBB2 2nd Ed.)

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Traveller canon lacks a Scout Service ship capable of transporting more than a few personnel along all links in the Jump-4 XBoat network, aside from the Jump-5 Lightning Class Cruisers. Even the Donosev Class Survey Scouts are only capable of Jump-3.

Thus, the Type ST Transport Scout.

[Note: please note the mouse-over comments such as this one. ]

Using a 199-ton custom streamlined hull, the transport scout is intended for personnel transfer duties along the XBoat network, as well as exploration, survey, and courier missions. It has jump drive-D, maneuver drive-B, and power plant-D, giving performance of jump-4 and 2-G acceleration. A 110-ton fuel tank provides fuel for three weeks of power plant operation at full output and one jump-4. Adjacent to its bridge is a Model/4 computer. There are four staterooms and no low berths. One unarmed triple turret is installed on one of the ship's two hardpoints; a second could be installed but would increase the ship's size to 200 tons. One air/raft may be carried in a specially-fitted hangar within the ship, though it is replaced by a modular stateroom when transporting passengers along the XBoat network. Cargo capacity is 3 tons. The hull is streamlined, and incorporates fuel scoops. The drives can tolerate unrefined fuel without difficultly. Sensors are Scout/Military grade unless specified otherwise.

The Transport Scout crew consists of a pilot, though the optional addition of a second turret not only requires a gunner for it, but also a medic and an engineer for regulatory reasons. The ship costs MCr122.31 in serial production, MCr136.9 individually.

Configured for personnel transport (with a stateroom replacing the air/raft), it can carry 4-9 passengers in addition to the pilot.


In the context of the game, it's how you build a Jump-4 version of the Type S Scout/Courier without resorting to LBB5 (it has the same capacity and crew requirements as the Type S). If you're running a Scout campaign and need to give your players Jump-4 to make a scenario work (and just slinging a drop tank under a Type S won't suffice for whatever reason), this does it. In-universe, it's useful for personnel transfers to or from the boonies, or for long-range/rift exploration missions.

It probably won't be loaned out through the Detached Duty program except as a reward for extraordinary accomplishments. But if your players somehow rack up a big win for the Scouts or the Imperium, it's an option...


This design bends the rules a bit in order to work under LBB2 (2nd Ed.). The first exploit is building it to 200 Td but including a hardpoint without a turret. Since that puts it below 200Td, it doesn't need a medic or engineer. Adding that second turret puts it at 200Td and thus requires medic and engineer crew positions (plus a gunner or two). The second is that it exploits the "Type Y Yacht Loophole" (in its strict interpretation) to reduce the normal 4-week power plant fuel requirement to three weeks, saving 10Td of fuel allocation. I'll cover that in the next post.

This is simply a way to shoehorn a Jump-4 Scout/Courier into the LBB2 framework. If the rules exploits don't fit with your version of the Traveller Universe, the same performance in 199 tons (with slightly different fuel, drives, and cargo) is possible under most other Traveller ship construction rulesets. Just build to J-4/2G with 4 staterooms and include an air/raft.

If all you need is J3/2G, it's possible in an otherwise stock Type S at TL-13 using LBB5 '81. There's room for a fuel processor, and it could even use the LBB2 100 ton standard hull (same total drive size as a matched set of Size A Drives) if you allow that as a house rule.
 
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Justification for using the Yacht Loophole:

In the "Express Bus on the XBoat Network" mission, it's justified because there will always be tankers or tenders available at XBoat stations from which to top off the tanks at the 100-diameter Jump Limit.

In off-the-network missions, it's justified by the TCS/JTAS#14 power-down rule (amortized to weeks instead of entire months). Other than during jump or combat, the ship only needs Pn-2 (to support the 2G maneuver drive). In Jump (and just before it), it needs Pn-4 for the jump drive; in combat, it needs Pn-4 to power up the Model/4 computer. Thus, it has one week of Pn-4 fuel (10 tons) for the jump, plus 4 weeks of fuel for Pn-2 (20 tons) normal-space operation.

Using the permissive interpretation of the loophole, it might only need 20 tons of powerplant fuel rather than 30 -- but that extreme isn't necessary here.
 
About the "yacht loophole" itself...

The canon Type Y Yacht (LBB2 2nd Ed., pp. 19-20) is specified as being able to do two jump-1s, but has fuel for 2J1 and only four weeks power plant operation. At the normal jump cadence of one jump every two weeks (LBB2 2nd Ed., p.4), two jumps would require four weeks. Thus, the Type Y is allowed to perform a jump with only two weeks of power plant fuel. This is the permissive interpretation of the loophole.

The strict interpretation is based on the Type Y description stating that the fuel capacity "... allows two successive jump-1." That is, it explicitly does not allow two J1 over the course of a month, but only back-to-back J1 over three weeks. Based on this interpretation, the minimum power plant fuel requirement is for one week of full power operation prior to the jump(s), and one week after the final jump exit. A ship that is only going to jump once therefore needs three weeks of power plant fuel.

Unless it's not a loophole, but instead is either a product of in-universe cheating or of a broken design -- that is, the Type Y was designed with insufficient fuel. The in-universe cheat is that construction of the Yacht design was authorized as doing a single jump-1 while having 3 months of power plant fuel (10 tons for one month, 20 tons for two more months) allocated. It's just that every single one of them ends up using the extra power plant fuel as jump fuel... who could have imagined? The obvious fix for the "broken design" problem is to replace 2.5 tons of cargo with 2.5 tons (1 week of Pn=1) fuel, so it can have a 1-week layover between jumps without running out of fuel. However, that also changes the "must have four weeks of power plant fuel" rule -- and if you're changing it one way, why limit it to just that change?
 
About the "yacht loophole" itself...

The canon Type Y Yacht (LBB2 2nd Ed., pp. 19-20) is specified as being able to do two jump-1s, but has fuel for 2J1 and only four weeks power plant operation. At the normal jump cadence of one jump every two weeks (LBB2 2nd Ed., p.4), two jumps would require four weeks. Thus, the Type Y is allowed to perform a jump with only two weeks of power plant fuel. This is the permissive interpretation of the loophole.

The strict interpretation is based on the Type Y description stating that the fuel capacity "... allows two successive jump-1." That is, it explicitly does not allow two J1 over the course of a month, but only back-to-back J1 over three weeks. Based on this interpretation, the minimum power plant fuel requirement is for one week of full power operation prior to the jump(s), and one week after the final jump exit. A ship that is only going to jump once therefore needs three weeks of power plant fuel.

Unless it's not a loophole, but instead is either a product of in-universe cheating or of a broken design -- that is, the Type Y was designed with insufficient fuel. The in-universe cheat is that construction of the Yacht design was authorized as doing a single jump-1 while having 3 months of power plant fuel (10 tons for one month, 20 tons for two more months) allocated. It's just that every single one of them ends up using the extra power plant fuel as jump fuel... who could have imagined? The obvious fix for the "broken design" problem is to replace 2.5 tons of cargo with 2.5 tons (1 week of Pn=1) fuel, so it can have a 1-week layover between jumps without running out of fuel. However, that also changes the "must have four weeks of power plant fuel" rule -- and if you're changing it one way, why limit it to just that change?

It's not a loophole.

The requirement for minimum power plant fuel is to sustain 4 weeks of operations at maximum power plant load. The LBB2 type-Y meets that standard. Since the type-A power plant yields Power Plant 1 in a 200 ton hull class, this means that 10 tons of fuel are needed for the power plant to sustain those 4 weeks of full power operations.

In ADDITION to that minimum for the power plant, the jump drives are also type-A yielding Jump 1 in a 200 ton hull. Jump 1 at 200 tons in LBB2 requires 20 tons of fuel, and the LBB2 type-Y has 40 tons of fuel for 2 Jump 1.

Total fuel tankage = 50 tons.

All it means is that 2 out of the 4 weeks of power plant endurance can be spent in jump before needing to refuel. Whether that means ...
Jump week + business week + Jump week + business week (refuel during)
... or ....
Jump week + Jump week + business week (refuel during)
... is up to the captain/owner of the ship to decide.

The requirement is for 4 weeks of power plant operation regardless of the number of jumps made during that time. However, as a matter of simple logistics, if you're going to be making multiple jumps before refueling, you'll want to make sure you have enough fuel reserve to keep your power plant operational after exiting your last jump so as to safely/consistently maneuver to a refueling point (starport, spaceport, ocean, gas giant, etc.).

Additionally, the 4 weeks minimum of power plant fuel is there as a safeguard against misjumps that last longer than 1 week. Per the Rules As Written (RAW) in LBB2.81, p6 ... a misjump can last 1D6 weeks(!) in duration. So with 4 weeks of power plant endurance, you can (theoretically) keep the power on for 4 weeks worth of misjump and exit with no fuel remaining (adrift, but alive, for a short time) and can hopefully be rescued after your life support systems fail. That's a 2/3 chance at survival in a misjump, rather than a 1/2 chance at survival in a misjump with only 3 weeks of power plant operations (1D6 result of 3 vs 4). Likewise, if a misjump takes 3 weeks or less (50% chance) with 4 weeks of power plant fuel, upon exit from misjump the ship will still have powerplant fuel and can maneuver in search of fuel to recover.

So in my mind, a significant portion of the justification for the "4 weeks minimum power plant fuel" requirement is to provide a safety margin against misjumps by starships (which can still happen with refined fuel combined with a lack of annual maintenance). It's basically a compromise on the safety margin assumed to be needed in the event of a misjump. After that, other considerations can start to come into play.
 
Your 200t loophole is invalid.

A turret has no displacement cost in CT LBB2, nor does a hardpoint. It is the fire control that takes up 1 displacement ton. To get two hardpoints you need a 200t hull, not a 199t one.

There is no need to fudge this by the way - it is fully within the rules as written to build a 199t custom hull - the only thing you need to do is install drives for a 200t hull to get the performance you require.
 
Your 200t loophole is invalid.

A turret has no displacement cost in CT LBB2, nor does a hardpoint. It is the fire control that takes up 1 displacement ton. To get two hardpoints you need a 200t hull, not a 199t one.

There is no need to fudge this by the way - it is fully within the rules as written to build a 199t custom hull - the only thing you need to do is install drives for a 200t hull to get the performance you require.
I wasn't clear on the displacement: it really should be 199.5Td (or so) with an empty hardpoint, 200Td with the turret mounted.

Look at canon deckplans. Turrets project from the hull rather than being flush to the surface. Yeah, there's the +/-10-20% deckplans guideline, but it's something that either does or does not increase the hull volume. I've yet to see a plan that includes dummy turret blisters on unusued hardpoints.

The point to the exercise is to make the crew size "selectable" through deciding whether or not to mount the second turret.
 
Apologies in advance for the rules lawyering (I made a career out of it during my youth, nowadays I do it mostly pro bono). :eek:

I wasn't clear on the displacement: it really should be 199.5Td (or so) with an empty hardpoint, 200Td with the turret mounted.

Except ... that's not how LBB2 works (nor LBB5 for that matter).

Hardpoints do not "add" to displacement.
Fire control for turrets installed on hardpoints DO consume displacement (internal displacement tons, to be precise).

Using LBB2 weapons only, that's 1 ton per weapon type in a turret (hence why Scout/Couriers with their dual turrets have 2 tons of fire control set aside for them). So a triple missile turret would need only 1 ton of fire control, but a dual turret with missile rack plus sandcaster would need 2 tons of fire control (1 ton per weapon type in the turret) as demonstrated by the classical Scout/Courier design we're all familiar with.

Look at canon deckplans. Turrets project from the hull rather than being flush to the surface.

Projecting from the hull or not makes no difference at the ship design rules level. What matters is the displacement (ie. volume) that the drives need to account for to yield their performance profiles (and whether everything "fits" inside of that displacement allowance). A 200 ton ship with 2 tons set aside for fire control does not ipso facto convert into a 198 ton ship without turrets on the hardpoints.

Or to put it another way, turrets are not something that can be jettisoned like L-Hyd Drop Tanks so as to change the overall displacement of a ship (with d-tanks versus without d-tanks).

Now, granted, LBB2 is a touch less finicky on this point than LBB5 is, but the point still stands. In general, ships do not gain or lose overall tonnage by installing or removing turrets from hardpoints. In fact, what would usually occur if there was no tonnage allocated to fire control in the design would be a loss of Cargo tonnage to allocate towards fire control for turrets added as aftermarket installations, rather than a change in the overall displacement tonnage total of the ship. So despite the fact that turrets "protrude" from the hull, the fire control for them gets accounted for as "internal" tonnage (volume) in the ship design rules, just like staterooms and cargo bays and everything else (except external fuel tankage or external cargo).

The point to the exercise is to make the crew size "selectable" through deciding whether or not to mount the second turret.

The way to accomplish that is to have tonnage allocated to fire control so turrets can be installed as aftermarket add-ons at no "cost" to the overall displacement of the ship (although at a cost in MCr, obviously) while also having enough accommodations aboard (staterooms) to house the Gunner(s) at the expense of passenger carrying capacity.

The problem you're really having here is that you can only mount 1 hardpoint per 100 tons of ship (LBB2.81 p15). You can't have it both ways where you're both under 200 tons (for crew requirements) and at 200 tons (for hardpoint allocations) at the same time.

Or to put it another way ... that hair don't split that way ... (or at the very least, I don't think it should...)
 
This design bends the rules a bit in order to work under LBB2 (2nd Ed.).
You are way past "bending" the rules, as already explained.


You must have 40 Dt power plant fuel, and that happens to last four weeks.
LBB2'81 said:
At a minimum, ship fuel tankage must equal 0.1MJn+10Pn, where M is the tonnage of the ship, Jn is the ship's jump number, and Pn is the ship's power plant rating.
No bend or wiggle room in that rule.

You may then use the powering down rule to eke out longer than four weeks duration, but note:
JTAS#14 said:
Ships which spend an entire 4 week period in powered down state reduce the fuel consumption of the power plant to the powered down level.
You must spend an entire four week period powered down to reduce fuel consumption, so you cannot perform J-4 during those weeks. This is not usable during normal operation, except perhaps for warships with very high Pn.



The first exploit is building it to 200 Td but including a hardpoint without a turret.
Turrets take no space, fire-control does (inside the hull). Removing a turret does not change the tonnage of the ship.

A hull is either 200 Dt with two hardpoints, or 199.9 Dt with one hardpoint, it can't shift between the two.

If you want a house-rule, just call it a house-rule, not a "loophole".

Since you have already invoked HG, the rules are clear when total tonnage can change:
L-Hyd tanks are installed outside the hull, and increase the total tonnage of the ship; drives are reduced in their efficiency based on the total tonnage of the ship. With tanks retained, efficiency is decreased, and jump capability is reduced; when the tanks drop away, tonnage is reduced, and the drive efficiency is increased.
Still does not change hull tonnage, hardpoints, or crew.
 
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Using a 199-ton custom streamlined hull
{snippity}​
It has jump drive-D, maneuver drive-B, and power plant-D, giving performance of jump-4 and 2-G acceleration. A 110-ton fuel tank
{snippity}​
Adjacent to its bridge is a Model/4 computer.
{snippity}​
The ship costs MCr122.31 in serial production, MCr136.9 individually.

Just on these design points alone, switching to a LBB5 design (streamlined flattened sphere, Jump-4, Maneuver-2, Power Plant-4, one jump 4 plus 4 weeks fuel (90 tons), bridge and model/4 computer) in a 200 ton ship yields 36 tons displacement remaining at a cost of MCr 148 at TL=13 before adding weapons and accommodations. So ... slightly pricier, but not THAT much more expensive ... and you get more internal tonnage to fit things into (which is the "real savings" at this end of the tonnage scale).

Personally I would use LBB5 rather than LBB2 for this endeavor, but that's just me. :eek:
 
...
So in my mind, a significant portion of the justification for the "4 weeks minimum power plant fuel" requirement is to provide a safety margin against misjumps by starships (which can still happen with refined fuel combined with a lack of annual maintenance). It's basically a compromise on the safety margin assumed to be needed in the event of a misjump. After that, other considerations can start to come into play.
Except that if it's providing a safety margin, it needs to actually provide one.

A conventionally-designed ship (one jump per trip) has a nominal two-week power plant fuel reserve after accounting for its jump and transit to/from jump limit. The Type Y on a double-jump trip has only a one-week reserve. After a pair of normal-cadence trips (jump on alternate weeks), that Yacht has no reserve fuel remaining.

Therefore, in-universe the Type Y breaks the intent of the 4-week fuel requirement. It should have at least 2.5 tons additional fuel (1 week of Pn-1) to support the extra week it's designed to spend in jumpspace that most other ships do not. But it doesn't, and that's a loophole. The almost-plausible next step is a 3xJump-1 ship with 4 weeks of power plant fuel: perfectly acceptable under the rules, but probably not legal in-universe if the rules reflect ship design safety regulations. The absurd step past that is something like a Jump-1 XBoat (4J1/0G, meant to be refueled at the 100 diameter limit before and after a string of 4 consecutive jump-1s) still only needing 4 weeks of fuel.*

Out of universe (that is, as an element of the game rules), the 4-week requirement serves two purposes. The first is to make it possible to disregard power plant fuel consumption -- for most gameplay purposes only jump fuel use is a constraint because ships have enough power plant fuel for whatever players want to do in-system. The second is to severely handicap small starship designs.



*Yes, jump duration varies. The variation probably averages out over 4 jumps (two of them longer than usual, two of them shorter than usual). This is just an example in any case, demonstrating that what the rules allow and what makes sense aren't always the same thing.
 
A conventionally-designed ship (one jump per trip) has a nominal two-week power plant fuel reserve after accounting for its jump and transit to/from jump limit. The Type Y on a double-jump trip has only a one-week reserve. After a pair of normal-cadence trips (jump on alternate weeks), that Yacht has no reserve fuel remaining.

Therefore, in-universe the Type Y breaks the intent of the 4-week fuel requirement.

The Rules As Written (RAW) do not imply nor explicitly state how much fuel reserve for power plant operation needs to be kept AFTER completing a jump (or jumps). Instead, the RAW specifies how much power plant fuel needs to be designed into the ship at the design phase, and that is set at a minimum of 4 weeks of operations, regardless of what is happening (or supposed to be happening) during those 4 weeks. Whether you jump once, twice or three times during those four weeks makes no difference to the required minimum 4 weeks of power plant fuel requirement.

Obviously if you intend to jump 4 times in a row, you'll want to have 5+ weeks of power plant fuel tankage ... but that's a side issue for a different design of ship.

So as far a the "naval architect" is concerned (and you can only get the skill from the Scout service in LBB6 ... go figure :eek:o:) at the design phase, all you need is 4 weeks of power plant fuel as a minimum. The issue that you're citing, fuel reserves remaining after making two jumps without refueling, is a matter for the ship's crew (specifically, the captain and/or navigator) to be aware of and work around so they don't wind up stranding themselves somewhere adrift without power because they exhausted their fuel due not refueling when they could (or should) have done so. It's not a design consideration, it's an operational (and economics) consideration once the ship is in service.

After all, how low you drain the fuel tanks before you top them up again is a crew problem, not a "naval architect" problem. The architect simply builds the reserve margin ... how the crew makes use (or abuse) of that margin to conduct their business is THEIR responsibility, not the architect's.

All it means is that 2 out of the 4 weeks of power plant endurance can be spent in jump before needing to refuel. Whether that means ...
Jump week + business week + Jump week + business week (refuel during)
... or ....
Jump week + Jump week + business week (refuel during)
... is up to the captain/owner of the ship to decide.

Either way, the type-Y would be expected to "splash for gas" prior to running out of fuel for its 4 week endurance. The remaining fuel margin might get LOW at times, but it should never go all the way down to zero (because at that point, the power plant shuts down and won't restart until there's fuel in the tanks again).
 
Apologies in advance for the rules lawyering (I made a career out of it during my youth, nowadays I do it mostly pro bono). :eek:
Well since you enjoy it I feel the need to point out your error :)

Using LBB2 weapons only, that's 1 ton per weapon type in a turret (hence why Scout/Couriers with their dual turrets have 2 tons of fire control set aside for them). So a triple missile turret would need only 1 ton of fire control, but a dual turret with missile rack plus sandcaster would need 2 tons of fire control (1 ton per weapon type in the turret) as demonstrated by the classical Scout/Courier design we're all familiar with.
It is 1 ton of fire control per hardpoint - regardless of the size of the turret or the weapon mix installed. I don't think I have ever seen anyone interpret it as you suggest.
 
Hey, Grav_Moped, I appreciate your work on this and think it will be useful to others in their games. As someone whose ship designs have been ripped to shreds, I think it's close enough for "government work". ;)
 
It is 1 ton of fire control per hardpoint - regardless of the size of the turret or the weapon mix installed. I don't think I have ever seen anyone interpret it as you suggest.

Granted.
In which case ... why does the canon Scout/Courier have 2 tons of fire control for 1 turret?
 
You are way past "bending" the rules, as already explained.

We may have to agree to disagree on this.

Rules have reasons, and they have implications.

Upthread, I talked about the reasons behind the 4-week requirement: keeping jump fuel the primary constraint on starship operations, and handicapping small ship designs. It's explainable in-universe as a safety requirement, that the canon Type Y design violates. The implication is that the safety requirement is not inflexible, and therefore the actual fuel requirement is also flexible.

The reason for the TCS power-down rule is to allow ships to hide in the outer system for more than a couple of strategic turns (weeks), while providing an upper limit on how long they can do so and ensuring that that a task force that comes back in to fight can't run away a second time. The implication is that power plant fuel consumption is flexible, and based on the ship's actual power use rather than the power plant's rated capability.

The reason for the breakpoint at 200/201Td is to create a carve-out to the crew requirements for small starships so smaller player parties (or single players) don't need a mob of NPCs just to run their ships. The implication is that 200/201Td is somehow significant from a regulatory standpoint. My point in using it here is to allow this ship to be on either side of that regulatory line as the needs of the game require. Without the second turret, it acts like a 100Td ship for combat purposes (it's an overgrown Type S that has J-4 capability and a small ability to absorb damage). With it, it acts like a 200Td ship and needs to be crewed accordingly -- which is the tradeoff for adding the turret.

I agree that these anomalies and rules don't actually spell out their implications, and that the black-letter rules don't allow for them. That said, the implications are perfectly clear. If you want to call it house-ruling, I don't have a problem with that. What I have a problem with is the implication that these are unreasonable interpretations of the rules.
 
We may have to agree to disagree on this.

Rules have reasons, and they have implications.

Upthread, I talked about the reasons behind the 4-week requirement:

You may believe or feel what you want, the rules clearly says:
At a minimum, ship fuel tankage must equal 0.1MJn+10Pn, where M is the tonnage of the ship, Jn is the ship's jump number, and Pn is the ship's power plant rating.
There are no exceptions or wiggle room.
 
You may believe or feel what you want, the rules clearly says:

There are no exceptions or wiggle room.

The rules also say that a Size C power plant in a 100Td hull* must have 60Td fuel, which is supposed to last one month.
They further say that if you strip that power plant out of the 100Td hull and literally install that specific power plant into a 600Td hull, it then is only required to have 10Td fuel, which is supposed to last for a month also.

No, that isn't an exception. But by not being an exception, it demonstrates that there's at least some wiggle room.




*It's a non-starship: 6G, Mod/1 computer, 1 stateroom -- and that's it. (Honestly, I'm not sure why you'd bother.)
 
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Yes, this is clear:
LBB2'81 said:
Each installed turret requires one ton of displacement committed for the installation of fire control equipment.

In which case, the only explanation that I can think of for why a Scout/Courier has 2 tons of fire control for one dual turret ... is to be able to fit a plasma or fusion gun into that turret (2 ton requirement), which were subject to brand new tonnage rules as of LBB5.80, p25, which was a revision from prior editions of LBB2 (and HG1?).

Still, something of an oddity for what is ostensibly supposed to be a LBB2 design in the Scout/Courier then.

:CoW: {insert Kinunir racing to the shipyard after rules updates meme here} :CoW:
 
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