To tow or not to tow ?

[maitrejeanth]

Several posts on the « what does the imperial navy need?” thread mentioned salvage ships. So my question is : how do you go about it ?

Let’s say a derelict ship is unable to manoeuvre. It has to be towed from somewhere in the system to the nearest starport. A ship, either a specialized unit like a salvage tug or any ship or boat with a sufficient powerplant capacity can come alongside and tow away the unfortunate vessel.
I don’t really think actual towing cables (hawsers, I think they are called) would be used : first of all, they would have to be very long, very resistant and would probably prove to be very awkward to use. Could there be special towing hardpoints on a ship’s hull ? The salvage ship could be lashed to the other ship, using cables, but keeping these as short as possible. An alternative would be magnetic docking plates that could mate snugly to these hardpoints. Dedicated salvage vessels could have huge magnetic plates, like a Chris Foss drawing of a space tug I have back home.
Therefore, I think that insystem towing operations should be feasible, though hazardous and difficult.

Now, things get more complicated when you have to take interstellar travel into consideration. Suppose our powerless ship got towed to the starport alright, but that it can’t be repaired insystem , or that her jump drive is wrecked as well. The ship is too precious to be left behind. How do you “tow” her two the nearest system, 1 parsec away ?
Supplement 9 has a modular cargo happily towing an asteroid behind her. The rock is wrapped into what is described as a “jump mesh” and looks indeed like the kind of shopping bag my old grandma used to bring vegetables from the market. Now, canonical literature on jump grids says that these intricate networks have to rigorously fit the hull of the starship in order to worl properly. There are very dark hints about what would happen to the jumping ship should the grid be even a **** hair misaligned. Now, is this compatible with that bilging, misshapen “jump mesh” ?
Now can starships simply dock alongside each other, fix mating collars , somewhat interconnect their jump grids and jump happily as one single ship ? Al this, of course, provided their cumulated displacements allow them any jump at all ?

Are there any other possibilities apart from special configurations like the X-boat and tender combo or the “million-ton fleet carrier Gorodish and asteroid monitor” arrangement depicted in supplement 9 ?

 

[Ben W Bell]

I have been spending some time wrestling with these very problems for towing and salvage ships for a Travellers Aide I'm working on. I think towing is feasible over system wide distances but is impractical for short ranges. For jump space distances you'd need to get some kind of tender in to carry it back.

 

[Rupert Boleyn]

Originally posted by Thierry Maitrejean:

Supplement 9 has a modular cargo happily towing an asteroid behind her. The rock is wrapped into what is described as a “jump mesh” and looks indeed like the kind of shopping bag my old grandma used to bring vegetables from the market. Now, canonical literature on jump grids says that these intricate networks have to rigorously fit the hull of the starship in order to worl properly. There are very dark hints about what would happen to the jumping ship should the grid be even a **** hair misaligned. Now, is this compatible with that bilging, misshapen “jump mesh” ?

My answer is simple - ignore all those references to a "jump grid" and use a TNE-style "jump coil" or "jump core". Such a device is contained entirely within the drive and it simply creates a field around the ship it's mounted in. As long as there's good contact between the two ships it'll 'see' them as being one ship and you'll hvae no problems (aside from capacity, of course).

This way of looking at jump drives also means you can have external cradles for small craft without worroying about whether they have grids biult into their hulls. Also, if jump grids are so precise, why doesn't surface battle damage ruin your abilty to jump? And don't the hulls of non-jump ships cost less? Unless the grid is part of the drive, of course, but if that's the case part of a jump drives volume should scale as displacement^2/3 rather than linearly with displacement.

 

[The Oz]

TCS had rules for recovery of ships that could not jump.

Ships that had lost their bridge or computer could still jump if they were "linked" to another ship for the jump; the ship helping had to have a computer and bridge at least as big as the ship being helped used to have. Apparently this is a physical linkage: it takes a week to set up and the linked ships cannot maneuver.

Ships without a powerplant or jump drive had to be carried with a tender or be repaired in place. Exactly how being carried by a tender works is not explained.

 

[far-trader]

A few minor nitpicks:

Battle damage does ruin your ability to jump, it's never defined in most of the systems if it's internal (i.e. the drive) or surface (i.e. the grid, where that's used) or both. The combat systems are in general too abstract and gross for that detail.

In most (if not all, my memory is blanking here and I'm not familiar with GT) of the design systems the hull cost is the same for spaceships (i.e. non jump) and starships. So it could be argued either way. No jump grid required or jump grid already included in all hulls, which does seem a tad odd unless...

The way I explain it uses the hull grid (NOT "jump grid") to manage not only the jump field but also the inertial damper field (something even the sub 100dT never jump capable small ships have and need) and the artificial gravity field (I don't have that in the floor plates, and again all spacecraft have it). Ship's docked externally link their hull grids with each other to align the gravity and inertial fields as well as any possible jump field. It's only when the jump field reaches a certain threshold (as defined by 100dT) that a stable jump bubble can be created.

Anyway that's the way I see it.

 

[Anthony]

Originally posted by far-trader:
A few minor nitpicks:

Battle damage does ruin your ability to jump, it's never defined in most of the systems if it's internal (i.e. the drive) or surface (i.e. the grid, where that's used) or both. The combat systems are in general too abstract and gross for that detail.

Actually, you can reasonably define it. If the damage result in the combat system says your ability to jump is restricted or lost, your ability to jump is restricted or lost. Otherwise, you're fine. By this logic, it's clear that in High Guard, at least, the jump grid is irrelevant, since the jump drive is on the internal explosion table.

 

[far-trader]

Originally posted by Rupert:

My answer is simple - ignore all those references to a "jump grid" and use a TNE-style "jump coil" or "jump core". Such a device is contained entirely within the drive and it simply creates a field around the ship it's mounted in.

I'm not picking on you Rupert, really. It was just that when you said TNE-style it didn't ring true. I had a chance to check and as far as I can see TNE is the first to assign a requirement for area to the jump drive. Seems indicative to me of there being a hull component. MT explicitly states (for the first time I think) that the jump drive is a "high yield power plant linked to an integral net in the craft's hull for initiating and maintaining the jump field." I see nothing in TNE to contradict this. MT doesn't deal with area though and in fact the damage application tables are the same as HGv2 (only flipped top to bottom).

Conclusions: There is officially a jump grid in the hull. It is not normally subject to direct significant damage and so is probably most often ignored (i.e. your ship will have other much more serious issues).

There is a reference (DGP Starship Operator's Manual, and yes I know

) to "more than 10% of the hull grid destroyed in a single location" being extensive hull damage and likely to cause the ship to be unable to jump. The same says an outer hull breach of more than 1 meter is sufficient for jump space to intrude into the hull in that area. I think most surface hits are going to cause a hole that big or larger.

Anyway, like I said I'm not picking on Rupert, just adding some background to the (slightly off topic) discussion here

 

[Rupert Boleyn]

Originally posted by far-trader:

I'm not picking on you Rupert, really. It was just that when you said TNE-style it didn't ring true. I had a chance to check and as far as I can see TNE is the first to assign a requirement for area to the jump drive. Seems indicative to me of there being a hull component.

However one of TNE's novels talks about jump coils, IIRC. I never claimed TNE was totally consistent.

 

[savage]

Thierry,

Interesting discussion especially since my group of players is about to attempt this...I think.


I have a number of simple rules that I've decided to implement;
- The total mass must be within the capabilities of the towing ship's system (computer, avionics, power plant...etc) but will be implemented at a reduced Jump or Manuever number.
- Bases roughly on Digest Group. Over 60% of the Grid must be available. I also add that builders logically "over grid" ships by 40% to assure damage does not impede a jump.
- A hardened attachment must occur in several places between the two ships (hardpoint, and enclosed docking system).
- The grids must be linked together. Builders make this readily possible through several grid attachment points in any ship hull.
- Battledamage must be patched.
- The engineering team will have to roll versus a DC12 for each item.

I actually designed a 1kt tender for this purpose. It has an optional hardened Grapple available as well as other toys.
I liked the boring old express boat tender and created 10 new versions of it for my campaign. They were very useable in Traveller society for many dirty jobs.
http://www.angelfire.com/empire2/savage/1WorldOrder/tenders/PB_T2_Transport.html


Savage

 

[maitrejeanth]

Thanks for the replies.
Some pretty neat stuff on your site, by the way, savage.

 

[savage]

Thierry,

Thanks, I appreciate that. My belief is that documenting and recording (on the web) things
we do in our campaigns is the best way to build
historical infrastructure to Traveller. I've implemented several things off other websites within my campaign. So, I hope more of us are planning to add their campaigns to the web.

The problem with doing a pocket empires is history. One needs to develop a variety of ships and military infrastructures. Some of the high guard ships are things players might find only in a battle debris field others are upgraded to the latest tech.

More to come. But if you have any suggestions please let me know.

Savage

 

[TheDS]

The most significant difference between an A and B starport is the capability to manufacture starships. Surely, this distinction is more than simply being able to make a single element of a ship.

It seems to me that a hull SHOULD have a grid to it. This makes a much more significant difference between starships and nonstarships, giving purpose to A and B starports. I would imagine that some one playing a strategic game, which had differences between A and B ports, would find a use for things like battleriders and the price differences between A and B ports. The tenders are made at A ports, the riders at B ports. All at the same time.

Otherwise, why not just make jump-coil factories and ship them to B ports so you can make starships there?

Having a coil implies (but doesn't force) that ship's drive volume is based on its longest dimension, not on its volume. Basically, a coil means you need a spherical jump field, which must envelop the whole ship, while a grid is simply run along the hull to envelop just what's needed.

A coil does allow you to simply say that you can attach any number of other ships to your hull, as long as they don't poke out of the field, everything is great. Little need for jump-distance recomputing, unless the carried ships poke out. It also means that your ship's config determines drive size; a sphere will be the most efficient design for jump drives.

On the other hand, a grid implies (but doesn't force) that you cannot attach anything to the hull without it also having a jump grid. What's the point of hull-mounting fighters if you can't take them with you? Basically, everything must be carried internal to the hull.

Jump cables, as were mentioned, would allow you to (relatively) easily carry any nonstarship to another system, and you can use them with just about anything; no need for specially designed transport ships.

So neither one of these solutions seems ideal.

Maybe we need to redefine exactly what a jump coil is? Or exactly what is required to get a ship to jump, with subcraft. Perhaps the coil runs throughout the whole ship, rather than just being some little toy in the engineering section? This allows us to go back to using ship volume as our drive size deteminant again. It also allows us to carry subcraft, and we simply have to boost the power to do it, as we'd done before.

With the coil being as integral to the ship as the spine, it seems like this will also help preserve the distinction between A and B ports.

 

[savage]

The most significant difference between an A and B starport is the capability to manufacture starships. Surely, this distinction is more than simply being able to make a single element of a ship.

It seems to me that a hull SHOULD have a grid to it. This makes a much more significant difference between starships and nonstarships, giving purpose to A and B starports. I would imagine that some one playing a strategic game, which had differences between A and B ports, would find a use for things like battleriders and the price differences between A and B ports. The tenders are made at A ports, the riders at B ports. All at the same time.

Otherwise, why not just make jump-coil factories and ship them to B ports so you can make starships there?

I cannot agree completely. 2 starports differ because of the cost in development of each port. Who cares where you build the ships. Ship the darn parts...wherever. The Kinunir discussion has made us consider an interesting possibility. Why not ship parts to lower tech ports for development ofhigher tech ships. Heaven knows that US tech and China tech is not equal. Yet china assembles end products for the US market....etc.

On the other hand, a grid implies (but doesn't force) that you cannot attach anything to the hull without it also having a jump grid. What's the point of hull-mounting fighters if you can't take them with you? Basically, everything must be carried internal to the hull.

Why not have both? Easy answer. Perhaps grids are cheaper. Also, there is no discussion as to the area of the pocket universe created by a grid. Why wouldn't the grid create a universe that is larger than the actual ship. I brought up in a different thread a simple question. If a spanner is left outside the ship. Does it travel with the ship into jump space if its close to the window... someone said sure. If the size of the fighter is fractional to the ship the area covered by grid may cover it. Yes there is no real definition of the grid. Do as you will in YTU.

Jump cables, as were mentioned, would allow you to (relatively) easily carry any nonstarship to another system, and you can use them with just about anything; no need for specially designed transport ships.

Not true. A good ref would make transport ships an easier jump to make. Pulling things through jump space is not the same. Its tougher but not impossible. Enclosed in the grid is safer.

And about fighters. Easier answer. If fighters are left attached outside one merely needs to release them. This is physically different than a launch.
Assuming each has gravitics they'll avoid crashing into each other... Yet one needs to consider the amount of mass outside of the grid. Better to deploy after jump and carry outside of the hull. Releasing and allowing to power them is a couple turn activity assuming a small squadron versus hours.

With the coil being as integral to the ship as the spine, it seems like this will also help preserve the distinction between A and B ports.

Not relevant. A and B starports have a cost distinction. By their nature manufacturing an A starport, upkeep and production of starships will be more expensive. A system might not be able to afford such an effort But this topic is different than towing vessels.

Savage

 

[savage]

The most significant difference between an A and B starport is the capability to manufacture starships. Surely, this distinction is more than simply being able to make a single element of a ship.

It seems to me that a hull SHOULD have a grid to it. This makes a much more significant difference between starships and nonstarships, giving purpose to A and B starports. I would imagine that some one playing a strategic game, which had differences between A and B ports, would find a use for things like battleriders and the price differences between A and B ports. The tenders are made at A ports, the riders at B ports. All at the same time.

Otherwise, why not just make jump-coil factories and ship them to B ports so you can make starships there?

I cannot agree completely. 2 starports differ because of the cost in development of each port. Who cares where you build the ships. Ship the darn parts...wherever. The Kinunir discussion has made us consider an interesting possibility. Why not ship parts to lower tech ports for development ofhigher tech ships. Heaven knows that US tech and China tech is not equal. Yet china assembles end products for the US market....etc.

On the other hand, a grid implies (but doesn't force) that you cannot attach anything to the hull without it also having a jump grid. What's the point of hull-mounting fighters if you can't take them with you? Basically, everything must be carried internal to the hull.

Why not have both? Easy answer. Perhaps grids are cheaper. Also, there is no discussion as to the area of the pocket universe created by a grid. Why wouldn't the grid create a universe that is larger than the actual ship. I brought up in a different thread a simple question. If a spanner is left outside the ship. Does it travel with the ship into jump space if its close to the window... someone said sure. If the size of the fighter is fractional to the ship the area covered by grid may cover it. Yes there is no real definition of the grid. Do as you will in YTU.

Jump cables, as were mentioned, would allow you to (relatively) easily carry any nonstarship to another system, and you can use them with just about anything; no need for specially designed transport ships.

Not true. A good ref would make transport ships an easier jump to make. Pulling things through jump space is not the same. Its tougher but not impossible. Enclosed in the grid is safer.

And about fighters. Easier answer. If fighters are left attached outside one merely needs to release them. This is physically different than a launch.
Assuming each has gravitics they'll avoid crashing into each other... Yet one needs to consider the amount of mass outside of the grid. Better to deploy after jump and carry outside of the hull. Releasing and allowing to power them is a couple turn activity assuming a small squadron versus hours.

With the coil being as integral to the ship as the spine, it seems like this will also help preserve the distinction between A and B ports.

Not relevant. A and B starports have a cost distinction. By their nature manufacturing an A starport, upkeep and production of starships will be more expensive. A system might not be able to afford such an effort But this topic is different than towing vessels.

Savage