Characteristics of a Space Tug?

[Thunderbolt]

I've just started a new space craft model.

As the physical design already suggests, this is no sleek jump ship, but a blocky and decidedly unglamorous ship.

I see this crate moving large ships or detachable cargo modules around, so it may not need any kind of jump drive at all? Conversely, it probably has huge manoeuvre drives combined with large thrusters.

Of course my question really is, what characteristics would a space tug have that might make it interesting as a PC ship once it has been pensioned off?

My current working theory is it might make a nice asteroid mining ship, especially if it has no need for jump drive, and has plenty of 'dynage' to spare.

 

[Seriayne]

Maybe a really oddly offset bridge, so POV could look around/over what it was tugging/pushing etc.

Drive section, connection/brace/clamp/magnetic section, offset bridge (or sensor clusters/cameras on booms maybe). Converting it to a PC ship might be tough though, because there might not be anything else besides the bare minimum.

If it was as salvage ship, ie. tugged things from world to world within system, instead of just cargo from a ship in orbit to a near dock, then it might have things like staterooms, extended life support, etc.

 

[Gray Lensman]

Jump tender

Since it may also need to be deployed in systems other than where it was built it would also need a Jump tender ala the tender for the SDB.

I thing the offset bridge is a cool idea ie:

http://dbdev2.pharmacy.arizona.edu/gallery/sf_two.html

What size were you envisioning?

 

[Thunderbolt]

What size were you envisioning?

A good question and one of my current dilemmas.

I've modelled some of the primary hull, but at some point I will need to start adding details like airlock hatches and of course the bridge; at that point I will have established its size.

I think it would have to be sub 1000 tons so as not to make it too big for players to inhabit.

 

[Seriayne]

Go oddball - a nice round ... uh 700 tons, just to be perverse?

Big enough to mount a few turrets, but most of the hardpoints impossible to utilize. That way you have something armed equiv to a 3-400 ton player vessel, shaped bizarrely, but nice and roomy inside (once you gut all the unnecessary bits) - either for cargo, or maybe they're like third or fourth owner after other modifications.

Someone put a snooker room in. There's tapestries in the lounge. Or make the architecture all Googie era, with inflateable or web-stretch plastic furniture.

Maybe the previous owner was into sensory deprivation - took a Std Stateroom and painted it black, or modeled the interior so he could sit in the lotus position and look at the fiber optic 'planetarium' like he was floating in space.

Or maybe everything's chrome and red, with nixie tubes and neon everywhere - and somehow integrated into the life support system (or so the dealer says) and you daesn't touch ANYTHING or the oxy mix will go off.

Or, wait ... I think this prolly belongs in its own thread >.O

 

[Icosahedron]

I've never really got my head around tugs.
In the world of internal combustion engines, you have gearing that makes craft like this powerful but slow. However, in space, thrust is directly related to mass and acceleration. Anything powerful enough to tug a big ship around is going to perform like a fighter when its unloaded.
If you solve that one, I'd be very pleased to hear about it.

 

[Andrew M]

Some tentative thoughts.. A single tug might not be what you need. If you are using reaction drives then you could not tow the load directly behind without it getting blasted by the exhaust. You could push the load but than needs you to line up with the centre of mass very accurately and a slight buckling in the object would throw this off pretty easily.

Grav tech could give you a lot of control. I am not sure what can be achieved with this, and how much energy it takes. Having a group of tugs allows more control because they can be arranged arround what you are towing. This is also more flexible, very important when you don't know what you have to deal with.

I think cattle drives might be an appropriate image, especially for asteroid mining. You have a selection of high yield planetoids which want to be taken from the outer system to an orbit around the starport. They have to get there in a tight bunch so that they don't become a hazard to shipping, so they would literally need to be herded to their destination.

 

[Andrew Boulton]

Make it 400dt and it can use the standard SDB jump shuttle.

 

[HG_B]

Anything powerful enough to tug a big ship around is going to perform like a fighter when its unloaded.
If you solve that one, I'd be very pleased to hear about it.

That IS the nature of space movement, or even any movement not involving mechanical gears. There is no "solve" for it.

 

[Thunderbolt]

All good suggestions.

I've got a plan to have what are effectively giant landing pads pointing out the front which it places against the side of the object its moving.

The design aesthetic is definitely close structure, big fat engine ports, skeletal frame joining bits together, pylons sticking out.

As for the speed thing, perhaps there is 'tug racing' in the far future, lots of forward speed but manoeuvring really sucks...

 

[Gray Lensman]

As for the speed thing, perhaps there is 'tug racing' in the far future, lots of forward speed but manoeuvring really sucks...

Perhaps not, if you use the Starship Operator's Manual where Manuever Drives can exert 25% sideways force.

 

[aramis]

I've never really got my head around tugs.
In the world of internal combustion engines, you have gearing that makes craft like this powerful but slow. However, in space, thrust is directly related to mass and acceleration. Anything powerful enough to tug a big ship around is going to perform like a fighter when its unloaded.
If you solve that one, I'd be very pleased to hear about it.

That IS the nature of space movement, or even any movement not involving mechanical gears. There is no "solve" for it.

The "big" solution is a drive which generates a field of induced momentum, rather than a thruster system. Anything within that field "falls" at a given rate of acceleration, no matter how small or large; bigger items than the field may wind up with severe torque shear, as only the part inside the field gets accellerated.

 

[leo knight]

Personally, I like the idea of the unexpectedly fast diamond in the rough. There was the classic SF novel "Rocket Jockey" by Lester del Rey. The hero enters a refitted asteroid tug in a rocket race around the solar system. Because of its workaday origin, it's tougher and more versatile than the purpose built racers. Think of it not as a bug, but a feature!

Here's a link:

http://en.wikipedia.org/wiki/Rocket_Jockey_(novel)

Enjoy!

 

[HG_B]

The "big" solution is a drive which generates a field of induced momentum, rather than a thruster system. Anything within that field "falls" at a given rate of acceleration, no matter how small or large; bigger items than the field may wind up with severe torque shear, as only the part inside the field gets accellerated.

I was talking outside total handwavium. Of course a GM can say, "It is X because I dictate."

 

[atpollard]

I've never really got my head around tugs.
In the world of internal combustion engines, you have gearing that makes craft like this powerful but slow. However, in space, thrust is directly related to mass and acceleration. Anything powerful enough to tug a big ship around is going to perform like a fighter when its unloaded.
If you solve that one, I'd be very pleased to hear about it.

I've given your statement some thought, and I believe that real world tugs are pretty fast when not pushing a giant ship around. Not as fast as a racing boat of similar horsepower, but a lot faster than the typical ocean yacht of the same displacement (and much lower HP).

However, the critical, defining issue with a water tug is that it serves a very real purpose - usually precision maneuvering in confined spaces to avoid hitting a docked ship or a bridge or a submerged hazzard. Outer space, in contrast, is simply vast and empty space with almost nothing to crash into. [Just read any of the old debates on pirates matching vectors with a merchant ship if you want more evidence that accidentally bumping onto another ship is really not a serious problem.]

So what Travelleresque problems could be solved by a Space Tug? Actually, one very common situation occurs to me: The 100 diameter jump shadow of a sun or gas giant.

Most commercial ships are only capable of 1G, and the safe jump distance from a typical size 6 world is about 960 thousand kilometers or 5.4 hours each way at 1G. A fast merchant capable of 2G could reduce the typical travel time to 3.8 hours. Faster drives offer diminishing marginal returns.

Now, imagine the colony on a moon of a Large Gas Giant carries on a brisk interstellar trade. The safe jump distance from the colony (lg gas giant) is 10 million kilometers or 17.6 hours each way at 1G. The less than 11 hour typical round trip to/from the jump limit is nearly a day and a half on this world. What if a tug were locally available to push commercial ships to and from the jump limit at 6G? Now the travel time to or from the jump limit is reduced back to a reasonable 7.2 hours.

Since the drives on a tug could operate nearly continuously, the Tug could be rented for three 8 hour trips per day or up to 83 trips per 28 day month. The cost to rent the tug would be about 1/83 the cost to charter it.

A world in a close orbit to its sun might be deep within the jump shadow of the sun, making the travel time at 1G even longer than the lg gas giant example, and the benefit of a 6G tug that much greater.

Just a thought.

 

[Gray Lensman]

Doh!

So what Travelleresque problems could be solved by a Space Tug? Actually, one very common situation occurs to me: The 100 diameter jump shadow of a sun or gas giant.

:nonono: You know, I would never have thought of that. Now that it has been brought to my attention......

What if the System Government REQUIRED all ships to use this service?
It could be that it is a High Traffic System.
It could be that it is a High Law System.
It could be that something is VERY valuable to smuggle either in or out.
It could be that the Tug Crews are ALSO the Inspection Teams.

Hmmmm........

Would be a good line of work for a stranded crew for a bit or a way to stay in-system while GM fleshes out next adventure.

Of course the Dual Role of the ship would put some constraints on it's design.

Could be an interesting exercise in ship design.

Good One AT!

BTW Thunderbolt, What system are you using for the stats?

 

[Seriayne]

:nonono: You know, I would never have thought of that. Now that it has been brought to my attention......

What if the System Government REQUIRED all ships to use this service?
It could be that it is a High Traffic System.
It could be that it is a High Law System.
It could be that something is VERY valuable to smuggle either in or out.
It could be that the Tug Crews are ALSO the Inspection Teams.

Hmmmm........

Would be a good line of work for a stranded crew for a bit or a way to stay in-system while GM fleshes out next adventure.

Of course the Dual Role of the ship would put some constraints on it's design.

Could be an interesting exercise in ship design.

Good One AT!

BTW Thunderbolt, What system are you using for the stats?

Cool ideas!

As well, could be near a political border, ie. Imperium - Vargr Space - don't want hotshot pilots who don't speaka d'Anglic zipping around either. Or Hiver who live near the K'Kree/neutral space interface where humans and other races might carry out inferface trading between the two.

 

[Thunderbolt]

BTW Thunderbolt, What system are you using for the stats?

I was thinking of going fully retro and CT Book 2, but might relent and go CT Book 5 if that works better.

 

[Gray Lensman]

I was thinking of going fully retro and CT Book 2, but might relent and go CT Book 5 if that works better.

Usually what I use too. IMTU only the Terran Confederation is allowed ships over 5000 Dtons. Think I will throw out a Armed Tug design myself real quick.

 

[Gray Lensman]

LBB2 Customs Tug

Type-CT Customs Tug Strictly LBB2

Hull dtons MCr
Displacement 400 400 40.000 Nonstandard, Unstreamlined

Drives
Maneuver M -23 48.000
Power Plant M -37 96.000

Fuel Tankage
PP & Maneuver -60

Bridge & Computer
Bridge -20 2.000
Computer 2 -01 2.000

Crew/Staterooms
Pilot 1 -04 0.500
Navigator 1 -04 0.500
Chief Engineer 1 -04 0.500
Engineer 1 -04 0.500
Medic 1 -04 0.500
Chief Gunner 1 -04 0.500
Gunner 3 -12 1.500
Sml Cft Pilot 1 -04 0.500

Cargo
Cargo Capacity -185

Armament
Hardpoints 4 0.160
Fire Control -04
Triple Turret 4 4.000
Beam Laser 12 12.000
Vehicles
Shp Boat 1 -30 16.000

Total Cost with Vehicles 225.160
Cost with Vehicles less 10% for Standard Design 202.644
Construction Time 16 months
Architect Fees 2.2516
___________________________________________________

Could have went with MD & PP of N but.....
Cargo could be used for extra fuel tankage/confiscated cargos, or More staterooms for a dedicated boarding party or even a couple of fighters :devil: ect.

Tug gets 6G by itself.

While pushing a standard 1G free trader (200 ton) with it's 1 ton of drive plus the 23 tons of the tug = (600 tons) 24 tons of drive = 4G which is still better than 1G as far as getting out to the jump limit.

While pushing a standard 1G Sub Merch (400 ton) with it's 5 tons of drive plus the 23 tons of the tug = (800 tons) 28 tons of drive (drive P) = 3G.

I guess the concept would work. This looks to be a bit much for a PC ship to me though.