MT Ship/Craft Design mysteries

[Carlobrand]

Working MT ship design, some anomalous results - no great surprises. I'm applying the errata - still getting some bizarre bits:

1) How does the frozen watch work? The game has me dividing crew by 1/1000 the ship's mass. That gets me numbers like 5 and 6, which I don't know what I'm supposed to do with. There's no way that's a frozen watch: the game applies sanctions if your crew level drops below half.

 

[McPerth]

Though I agree it's not specified in the rules, as I understand it, Frozen Watch should go in crew sections (so, if your ship has 20 x 5 men crew sections, you must have the FW in groups of 5), so that you can replace your loses as they occur.

Off course, that's just my interpretation, as rules are really vague on the subject.

 

[Carlobrand]

Okay, now that starts to make some sense. The crew is organized in sections, crew losses are taken in sections, and the frozen watch is set up in sections to replace those losses, presumably as they occur to keep the ship at strength.

Thanks!

 

[Carlobrand]

Sorry to post after myself again, but I'd rather have this in the same thread than start another thread on basically the same issue.

So, I'm continuing to work on my pet project, which is an excel form that will handle Megatrav ship-building - thus the questions in this thread. It's actually coming out quite well, aside from the issue of not matching any of the published Megatrav designs, which appears to be an errata issue. It lines up pretty well with the Traveller's Journal Battlecruiser Regal example, which gives me some confidence - though there are still minor points I'm trying to iron out.

Inasmuch as Megatrav's design sequence is universal, everything from ground-borne motorcycles up to spacefaring superdreadnoughts, I've tried to make the spreadsheet universal as well.

So ... has anyone here had any experience with MegaTrav vehicle design? As in: can anyone explain why - when I plug the venerable Imperial Encyclopedia g-carrier into my design - I come away with something that very nearly matches their g-carrier but costs less than MCr 2, while the official Imperial Encyclopedia entry comes in well over MCr 14? I can't for the life of me see anything that could add MCr12 to the cost.

 

[Hyphen]

I can't for the life of me see anything that could add MCr12 to the cost.

Profit margin.



For a more serious answer: the original G-Carrier price was pulled out of the air when CT was written. The design rules are MT's port of Striker, written a few years later. The costs do not match each other. trendi's TL 9 AirCar (members.tip.net.au/~davidjw/tavspecs/trendi/aircar.htm) is twice as fast as an air/raft and costs Cr144,000 to build (although we don't sell it for that, of course; we sell it for Cr500,000, this undercutting the std vehicle while still making a profit...).

If you look at the Unresolved G-Carrier, there's a text dump of my MT spreadsheet for the vehicle; it may help test yours, although I don't guarantee it...

Look under Tavonni Specialties for trendi, then the vehicles section.

 

[Hyphen]

Something I forgot to ask: do you have the latest MT errata? There are quite a few changes from the original publication.

 

[Timmy]

The other issue might be that they didn't port the price modifications for such things covered in Book 4 Mercenary to the imperial encyclopedia. For what its worth, perhaps you should take the Imeperial Encyclopedia, 101 Vehicles and Shattered Ships of the Fighting Imperium vehicle listings as general ideas and use your spread sheet to produce more optimised results. For example, the Sepoy APC detailed in 101 Vehicles (TL8) has a armour value of 23, a loaded weight of 38 tonnes and an on road speed of 300 km/h. If this is appropriately reworked, you get results more like Armour 9, loaded weight 7.2 tonnes and on road speed of 176 km/h. The off road speed drops from 60 km/h to 53 km/h, but it is a much more reasonable vehicle that results.

 

[Carlobrand]

I have incorporated the errata. I don't have 101 vehicles, so that's not an option. I have Imperial encyclopedia - that's where I'm running into issues with the g-carrier - characteristics are real close, but the cost is way different. I'm learning that it's not possible to reproduce the canon MT ships exactly, apparently because they don't incorporate the errata, but I suspect also because some writers made mistakes themselves or misinterpreted rules. Makes it difficult to proof my spreadsheet, and you know how spreadsheet design goes - it's like making cream of wheat: just when you think you did it perfect, more lumps show up.

 

[christopher.boote]

Just assume that every single vehicle in MT is wrong in some way, and you'll be fine
From what I can see, Powerplant costs and fuel requirements are off by a factor of 10 in the published designs

So what are your choices...
Design your own and live with the differences
Design them at a lower tech (that normally bumps the price up a little, but not much)
Assume they are TL15 GCarriers, being sold to a TL9 world - that will multiply the price by 220% at least
Assume they are the 3I equivalent of £750 ashtrays and £300 hammers

My GCarriers come out at the following prices
TL 9 - MCr3.95
TL10 - MCr2.44
TL11 - MCr2.37
TL12 - MCr2.33
TL13 - MCr2.31
TL14 - MCr2.57*
TL15 - MCr1.97

So I think we're both working along the same lines here

*The price rise here is due to the (broken?) increase in power a TL14 RPA Plasma gun needs over a TL13 one

 

[Carlobrand]

Yeah, that's more on target, although I decided on my own to spring for the TL-9 point defense fire control, upped the cost by 200 thousand credits - and well worth the price.

 

[77topaz]

The TL14 increase in price looks like an error.

 

[christopher.boote]

I'm quite willing to believe I've made an error
Here's my working if someone wants to check it out

Hull				UCP	 Power		 Volume		Weight		Cost
Chassis	8			8			-108.000	 5.700		   10,000
Config	Box						   0.000	 0.000		   -4,000
Streamlining	SL		4SL			   5,000
Armour	10 Bonded Superdense	10G					 1.995		   37,500
-------------------------------------------------------------------------------------------------
Hull Totals				0.000		-108.000	 1.995		   37,500
-------------------------------------------------------------------------------------------------

Power				UCP	 Power		 Volume		Weight		Cost
-------------------------------------------------------------------------------------------------
Power Plant	TLE Fusion		-42.000		   9.333	28.000		1,866,660
-------------------------------------------------------------------------------------------------

Locomotion			UCP	 Power		 Volume		Weight		Cost
Type	Standard Grav					
Thrust	75 tons				  7.500		   1.500	 3.000		  150,000
Type	TL14 Avionics			  0.020		   0.100	 0.050		   16,000
-------------------------------------------------------------------------------------------------
Locomotion Totals			  7.520		   1.600	 3.050		  166,000
-------------------------------------------------------------------------------------------------

Fuel					 Power		 Volume		Weight		Cost
-------------------------------------------------------------------------------------------------
Endurance	240 hrs  10/30 days			  10.080	 0.706		      353
-------------------------------------------------------------------------------------------------

Comms					 Power		 Volume		Weight		Cost
-------------------------------------------------------------------------------------------------
Radio	System (1,000AU) x 1		  0.010		   0.020	 0.010		  150,000
-------------------------------------------------------------------------------------------------

Sensors					Power		 Volume		Weight		Cost
EMSActArray	VDistant (50km)		  0.050		   0.010	 0.005		  100,000
EMSPassArray	VDistant (50km)		  0.010		   0.002	 0.001		   20,000
-------------------------------------------------------------------------------------------------
Sensor Totals				  0.060		   0.012	 0.006		  120,000
-------------------------------------------------------------------------------------------------

Weapons					 Power		 Volume		Weight		Cost
-------------------------------------------------------------------------------------------------
RP Plasma RPA-14 x1			 31.700		   0.020	 0.020		   16,000
-------------------------------------------------------------------------------------------------

Environment				 Power		 Volume		Weight		Cost
Basic Environment over 108.000 kls	  0.108		   0.540	 0.540		    1,080
Basic Life Support over 108.000 kls	  0.108		   0.540	 0.540		   32,400
Inertial Compensator over 108.000 kls	  2.160		   1.080	 2.160		   27,000
-------------------------------------------------------------------------------------------------
Environment Totals			  2.376		   2.160	 3.240		   60,480
-------------------------------------------------------------------------------------------------

Controls 				 Power		 Volume		Weight		Cost
Control Panels	Holographic Linked
	x 12				  0.024		   0.360	 0.240		   12,000
Add Ons	Heads-up Display
	x 1				  0.005		   0.500	 0.200		   20,000
Computer/0	
	x 2				  0.002		   1.000	 0.200		  120,000
-------------------------------------------------------------------------------------------------
Control Totals				  0.031		   1.860	 0.640		  152,000
-------------------------------------------------------------------------------------------------
 
Vehicle Stations 			 Power		 Volume		Weight		Cost
Roomy		6			  0.000		  24.000	 0.120		      600
Extended Occupancy			  0.000		  24.000	 0.120		      600
-------------------------------------------------------------------------------------------------
Vehicle Station Totals			  0.000		  48.000	 0.240		    1,200
-------------------------------------------------------------------------------------------------

Cargo Hold				 Power		 Volume		Weight		Cost
-------------------------------------------------------------------------------------------------
Cargo Hold	27kls 2 tons				  27.000	27.000	
-------------------------------------------------------------------------------------------------

=================================================================================================
Grand					 Power		 Volume		Weight		Cost
Totals					 41.697		 100.085	65.807		2,570,193
=================================================================================================

 

[McPerth]

I see a curious paradox in your design...

As you need 42 MW power, and TL 14 fusion PP gives 3 Mw/kl, you'd need 14 kl pp to have the power you need...

But the efficiency chart makes that power plant (being 14+ kl) to triple output, so giving you 126 MW...

At 9.33 kl, as your design shows, the output would be 28 Mw, but if you enlarge it to 10 kl, as efficiency doubles your output, you have 60 MW power...

So, I'm afraid the minimum PP you'd need for your design is those 10 kl, even if that gives you quite more power than needed, as any smaller PP loses the efficiency advantage and gives you only half of its power, not reaching what you need. I'd suggest you to use this power to upgun your design to a RFX14, by reducing a little your cargo capacity, and even then you'll have a little spare power.

Sorry if this adds to the mess, instead of answering questions, but rules are what they are...:devil:

 

[Carlobrand]

I'm quite willing to believe I've made an error
Here's my working if someone wants to check it out

Hull				UCP	 Power		 Volume		Weight		Cost
Chassis	8			8			-108.000	 5.700		   10,000
Config	Box						   0.000	 0.000		   -4,000
Streamlining	SL		4SL			   5,000
Armour	10 Bonded Superdense	10G					 1.995		   37,500
-------------------------------------------------------------------------------------------------
Hull Totals				0.000		-108.000	 1.995		   37,500
-------------------------------------------------------------------------------------------------

Power				UCP	 Power		 Volume		Weight		Cost
-------------------------------------------------------------------------------------------------
Power Plant	TLE Fusion		-42.000		   9.333	28.000		1,866,660
-------------------------------------------------------------------------------------------------

Locomotion			UCP	 Power		 Volume		Weight		Cost
Type	Standard Grav					
Thrust	75 tons				  7.500		   1.500	 3.000		  150,000
Type	TL14 Avionics			  0.020		   0.100	 0.050		   16,000
-------------------------------------------------------------------------------------------------
Locomotion Totals			  7.520		   1.600	 3.050		  166,000
-------------------------------------------------------------------------------------------------

Fuel					 Power		 Volume		Weight		Cost
-------------------------------------------------------------------------------------------------
Endurance	240 hrs  10/30 days			  10.080	 0.706		      353
-------------------------------------------------------------------------------------------------

Comms					 Power		 Volume		Weight		Cost
-------------------------------------------------------------------------------------------------
Radio	System (1,000AU) x 1		  0.010		   0.020	 0.010		  150,000
-------------------------------------------------------------------------------------------------

Sensors					Power		 Volume		Weight		Cost
EMSActArray	VDistant (50km)		  0.050		   0.010	 0.005		  100,000
EMSPassArray	VDistant (50km)		  0.010		   0.002	 0.001		   20,000
-------------------------------------------------------------------------------------------------
Sensor Totals				  0.060		   0.012	 0.006		  120,000
-------------------------------------------------------------------------------------------------

Weapons					 Power		 Volume		Weight		Cost
-------------------------------------------------------------------------------------------------
RP Plasma RPA-14 x1			 31.700		   0.020	 0.020		   16,000
-------------------------------------------------------------------------------------------------

Environment				 Power		 Volume		Weight		Cost
Basic Environment over 108.000 kls	  0.108		   0.540	 0.540		    1,080
Basic Life Support over 108.000 kls	  0.108		   0.540	 0.540		   32,400
Inertial Compensator over 108.000 kls	  2.160		   1.080	 2.160		   27,000
-------------------------------------------------------------------------------------------------
Environment Totals			  2.376		   2.160	 3.240		   60,480
-------------------------------------------------------------------------------------------------

Controls 				 Power		 Volume		Weight		Cost
Control Panels	Holographic Linked
	x 12				  0.024		   0.360	 0.240		   12,000
Add Ons	Heads-up Display
	x 1				  0.005		   0.500	 0.200		   20,000
Computer/0	
	x 2				  0.002		   1.000	 0.200		  120,000
-------------------------------------------------------------------------------------------------
Control Totals				  0.031		   1.860	 0.640		  152,000
-------------------------------------------------------------------------------------------------
 
Vehicle Stations 			 Power		 Volume		Weight		Cost
Roomy		6			  0.000		  24.000	 0.120		      600
Extended Occupancy			  0.000		  24.000	 0.120		      600
-------------------------------------------------------------------------------------------------
Vehicle Station Totals			  0.000		  48.000	 0.240		    1,200
-------------------------------------------------------------------------------------------------

Cargo Hold				 Power		 Volume		Weight		Cost
-------------------------------------------------------------------------------------------------
Cargo Hold	27kls 2 tons				  27.000	27.000	
-------------------------------------------------------------------------------------------------

=================================================================================================
Grand					 Power		 Volume		Weight		Cost
Totals					 41.697		 100.085	65.807		2,570,193
=================================================================================================

TL14? Everything seems to be right. Why are you cutting the occupants by making it extended occupancy?

Quick thought 1: I get a top speed of 120 kph and a NOE speed of 30. The TL14 avionics are not serving a purpose.

Quick thought 2: add a basic point defense module; you've already got the rapid-fire weapon to serve it. 200 thousand credits to save 2.5 million and associated lives, should be worth the cost.

Quick thought 3: It's not part of the usual package, but obscuration devices can save your life in a tight spot. Smoke discharger's cheap and can help cover a hasty withdrawal. I'm very fond of low caliber howitzers firing smoke or chaff rounds, but that doesn't seem to have been carried over from Striker.

Quick thought 4: Most of the time with vehicles, accessing the machine spaces involves leaving the vehicle - there's not a whole lot of the engine compartment you can access from inside unless it's specifically designed for that. And most maintenance, aside from emergency repairs, will be done in a garage or other sealed setting; you won't generally have the equipment in the vehicle for more than emergency repairs. You can save a wee bit by not extending life support to the machine spaces - the fusion plant and drives - since nothing's actually living in there.

I see a curious paradox in your design...

As you need 42 MW power, and TL 14 fusion PP gives 3 Mw/kl, you'd need 14 kl pp to have the power you need...

A power plant of volume 6+ Kl gets a 50% boost, so his plant is sized correctly. 9.33x3x1.5=41.985Mw. However, I agree that having gone to 9.33, it's worth it to go to 10 and go for the more powerful, longer range gun.

 

[Carlobrand]

Seeking to clarify a couple of more points:

MegaTraveller Referee's Manual, Ship design, P86
"A craft’s streamlining affects its speed when operating in a
standard atmosphere. ... Unstreamlined: 300 kph is top speed. Compute all other speeds from this 300-kph top speed level..."

No change noted in MT Errata 2.2. However, regarding unstreamlined ships, Errata clarifies, "Many protrusions and irregularities exist which significantly increase the vessel’s drag, making it difficult or impossible to operate the craft in an atmosphere at any high rate of speed. Unstreamlined craft cannot land on a world with an atmosphere of 2 or greater, and cannot skim gas giants for fuel."

Option 1: the unstreamlined speed is intended for unstreamlined ground craft, like that TL7 sedan you souped up for the stock car race. Unstreamlined spacecraft can't enter atmosphere, and you can't build an unstreamlined flying craft.

Option 2: the unstreamlined speed is intended for all craft. You can build an unstreamlined flying craft - provided its propulsion provides all the lift: for example, a cube that hovers like a helicopter, more of a floating building than a flyer, a bit of an engineer's nightmare, but if you're dead set on having a floating cube then it's doable. Be careful about where you put the drives, there's a center-of-gravity issue.

You just might be able to hover your unstreamlined ship down on maneuver drives from orbit to the surface to bail your landing party out of some jam, maybe drop supplies or find some way to haul them aboard. See, if you can put out more than 1-G, then you don't need to maintain orbital velocity - you can decelerate in vacuum to synchronize with the planet's rotation, then hover down. It's slow, 'cause you're still actually faster than the planet's rotation and are having to work off that excess velocity as you go down, but it's workable given the fantastic nature of the game tech. I wouldn't be thrilled about trying to pilot the thing down backward on its maneuver drives - I've got a bad feeling the thing's center of gravity may betray it in a stiff crosswind, but it depends on how effective your gyros and maneuvering thrusters are and how nice your game master is, and maybe how lucky you are with the dice; not something I'd recommend unless an emergency gave you no other choice. Still can't land - well, rules say you can't: if you're built for orbit or at best landing on size-2 worlds, you aren't built to bear your weight on a size-8 world without taking damage and maybe ending up falling over, but if you're that purpose-built weird cube balanced for (slow) atmospheric flight, I can't see why you wouldn't have the proper landing feet installed.

Second: autofire
Striker used to have an autofire DM to hit for things like machine guns. Am I correct that it's absent from MegaTrav? So ... if you toss more lead at someone, your odds of hitting him don't change? Rapid fire makes sense, you're spraying fire, but I'd have expected my three-round burst to count for more than the odd chance of hitting a bystander. Am I missing something?

Third: crashing.
Per MegaTrav, a streamlined but non-airframe flying vehicle - like the venerable air/raft - that loses power comes falling down like a rock. An airframe vehicle descends a bit more slowly, gliding down. And then there's the landing - a task roll to avoid crash landing. Game applies this to "Flying vehicles which lose their locomotion," which would seem to include the unfortunate air/raft plummeting down at or near terminal velocity. Is that right? Doesn't make sense.

And the game (Player's Manual) offers the glide option to airframes only if the vehicle loses locomotion - if it's the power plant that goes south, the vehicle plummets like the unlucky air/raft. Why? Errata for Referee's Manual declares, "An airframe craft can glide to a landing without power if necessary," but there's no errata changing the Player's Manual entry. Starship Operator's Manual describes the fusion plant as having batteries used to start it up - wouldn't these be set up to provide a brief bit of emergency power for flight controls and control surfaces if the power plant got shot up - or is it assumed that they're crippled along with the plant? Wouldn't the controls have some sort of integral emergency battery or small power unit to make sure the flight controls and control surfaces functioned for at least long enough to get you to the ground?

 

[77topaz]

Second: autofire
Striker used to have an autofire DM to hit for things like machine guns. Am I correct that it's absent from MegaTrav? So ... if you toss more lead at someone, your odds of hitting him don't change? Rapid fire makes sense, you're spraying fire, but I'd have expected my three-round burst to count for more than the odd chance of hitting a bystander. Am I missing something?

?

Wouldn't you roll for every shot fired? And since a machinegun shoots a lot, the chances would be higher? Or would it be too arduous to roll for every single bullet fired?

 

[aramis]

You can, indeed, build USL flying craft... they are slow. Proof is in 101Vehicles.

 

[Carlobrand]

sigh ... one of the books I don't have.

 

[Carlobrand]

Wouldn't you roll for every shot fired? And since a machinegun shoots a lot, the chances would be higher? Or would it be too arduous to roll for every single bullet fired?

Wait, you're right. Errata 2.2, for the Player's Handbook: "Page 72 and 73, Danger Space, Group Hits and Autofire (clarifications and additions): ...
The firing unit has considerable freedom when specifying which adjacent targets—the attacking unit may actually apply all of its autofire attacks to the primary target if it wants to, as long as no other potential targets exist along the line of fire in the same range band. In any case, each autofire attack requires its own roll."

(I will be ecstatic if they ever get around to offering a version that has all the errata edited in.)

That makes more sense for the vehicle-mounted RP weapons. Combat vehicles don't tend to cluster so tightly that additional autofire targets make sense, but being able to crank off additional tries at hitting the target is useful.

Doesn't impact Point Defense though. I would have expected a weapon with a higher rate of fire to be more effective in Point Defense.

Add another: why does a laser have a danger space AND additional autofire targets. Errata 2.2's added a danger space that the original rules did not consider. The more powerful the beam, the wider the danger space - 15 meters for a 10Mw laser, for example. Now, danger space secondary hits go down in penetration by half for each square (1.5m) away from the primary target. I've never heard of a laser that filled a 15 meter space and degraded from centerline out. Are we dealing with superheated air or something, and if so does that rule apply only in atmosphere? Or are those considered "brush" contacts, exposed to the beam more briefly than the primary contact?

My impression of the Traveller laser - especially the beam laser - is that while brief, it's not instantaneous. I can't see any other reason to give an autofire bonus to a beam - it has to last long enough for you to engage more than one target, maybe a second. Still, I'm having trouble wrapping my mind around the idea of both a danger space with degrading penetration and multiple autofire targets with full penetration.

 

[Carlobrand]

Question: agility

The explanation for it is ... entertaining, but the basic mechanic makes sense: more extra power = more agile, more massive = less agile. The maximum agility for a spacecraft is 6.

Now here's the puzzler: the maximum agility for a spacecraft is 6, regardless of the rating of the maneuver drive (or, presumably, gravs)?

With the drives drawing power, and the mechanic based on excess power, I can increase the agility of Ship-A by constructing it with a lower-rated drive. I could conceivably construct an agility-6 ship around a 1-g maneuver drive. It wouldn't be very good at running away, but it would be very good at dodging. Do I understand that correctly?

(And, if I am understanding it a'right, then why can I not achieve higher agility by throttling down that same drive to 1-g, using less power and diverting the extra to agility?)