Jump-4 X-boat Tenders

[Starviking]

Ah - and to think - all those silly Subsidized Merchants - all this time they could have been doing J-2 and 3Gs with a small computer upgrade... all they needed to do was open their cargo bay doors!*

Heck - use a ton for upgrade to Model 2bis and ditch the 20 dton launch and they could make J-3 with plenty of PP fuel left over! (Or use the launch's 13 tons cargo for fuel - with only 3 tons for PP, though one could lose a stateroom/lowberths, etc. to squeeze in more...)

The problem with metagaming the rules in this way is that it 'breaks' the existing designs in terms of what was possible, yet wasn't done.

Not to say exceptions can't be made - Mark's Annic Nova is a prime example of that.

*Converting the 400 dton to 200 dtons with C rated drives. The 50 tons of fuel would only get them J-2, and the computer needs upgrading to 1bis (no extra tonnage).

For a Subbie that would both involve a no-cargo run, and having to reinforce the cargo bay wall to prevent jumpspace intrusions. There's also the question of how big an entry into an open space in a ship would be needed to alter the ship's displacement. Whilst I'm not sure about other ships - the Tender's doors take up one whole side of the hangar bay and some of the two adjacent sides, which I think would lower displacement.

I wouldn't call my suggestion metagaming, it all revolves around the face that jump drives are limited by hull displacement - and displacement is the volume *enclosed* by the hull.

 

[Starviking]

The High Guard rules allow you to design a dispersed structure hull that you can add ships or components to that would meet your needs.

And to use rules for odd configurations, I could design a 400dt closed structure that looks like an X-boat Tender with open doors, fit a 20 dt Jump Drive (MT/TNE) and she'll be capable of J-4.

The "open the bay doors" idea falls apart on numerous levels for all other ship hulls, which are designed as X shape. (X = pick a valid hull type). Remove part of that shape and the performance of the hull under stress will suffer.

Safety engineering would dictate that hull stresses should not be carried by a part of a vessel that can be moved out of the stress path. Also, my 'open the bay doors' suggestion applies to jumps only.

Using the same logic, if I create a vacuum in an closed cargo bay/fuel tank/empty stateroom, I also reduce my displacement tonnage. Clearly something is wrong with this idea...

I disagree - you'd need to have the cargo bay significantly open to vacuum, the fuel tank would need its exterior walls blown - and the stateroom the same. This is not about vacuum per se - but the volume enclosed by the hull.

But a similar effect can be achieved several ways. Modular ships & ship components is one. Modular cargo holds is yet another. Most modular systems are built on Dispersed structure hulls.

Other options are the use of drop tanks and external demountable fuel tanks which by extension could be external demountable cargo holds.

True, and we have the Clipper in TNE and the Modular Freighter in MegaTraveller on those principles.

My suggestion was for a way for the X-boat Tender to drastically increase its jump range if needed - not for a variable jump cargo ship (I think there's one in Fighting Ships?). Variable jump ships are very nice though

But opening the cargo bay doors, your air lock and creating vacuums in non-essential areas of your ship, will not decrease the volume your ship displaces as determined by your hull.

With clam-shell style doors wide open, you have actually increased your volume...

I'm afraid I completely disagree on that. Enclosed hull volume will go down - this is in 1-to-1 correlation with displacement.

 

[Starviking]

Tenders are designed to tend, not to go into empty space and fetch lost X-boats. It's stranger that they have jump drives at all, seeing as they're designed to stay in one place for most of their careers. I can only imagine that it's some sort of 'belt and suspenders' notion (or perhaps a fat bribe by a manufacturer of J1 drives ) and that any tender that needs to be placed 4 parsecs away will be taken there by a 10,000T freighter.


Hans

That's a valid point, though perhaps the jump drives are for getting around system - not jumping to other systems. Also, it does pay to minimise the amount of vessel types any service has, as long as it does not impinge significantly on its performing its main roles. An X-boat Tender that can make a rapid recovery and return to station could be seen as a worthwhile ability as opposed to having a recovery ship on the books.

 

[far-trader]

In brief the points that led me to the conclusion that the X-Boat Tender was capable of J4...

First and most telling is the drives. Type H (LBB2 build) for a 1000ton hull do indeed give performance of J1, 1G and P1. However so would much smaller and cheaper drives in the same hull. With fewer engineers required as crew. Odd no? Until you look up the table to where Type H drives cross the 400ton hull line (being the 1000ton hull minus the huge hanger). Well how about that! J4, 4G, and P4. Isn't that nice of them to make the performance required for getting the tenders to those distant and remote X-Boat stops. I don't see them being ferried into those systems by some huge jump ferries that would be busy with other chores.

Second hint is the hardpoints. Only 3 on a 1000ton hull. A bit sparse for a military ship no? Not if the hull is actually only 400tons because the hangers don't provide the area for the other 6 hardpoints. I'd even see some variants with an extra hardpoint (4 total) to max out the defenses.

Now you might argue that the Model/3 computer isn't enough for J4, but in the first rules it was. The limit wasn't by computer model but by program capacity (iirc). As well it could be a Model/3 bis in the first edition of HG and permit J4. Personally I just make it a Model/4 anyway just to match the capacity of the X-Boats electronically and technically.

I've seen arguments against allowing the doors to be open to space and thereby decreasing the tonnage. But note in the description it permits ships to hang out of the hanger bay with the doors open, as long as the total tonnage does not exceed 600tons. That hints strongly to me at the bay being exposed with no issues, and even possibly permitting less than 600tons (with appropriate performance improvement).

All I can say is it works for me, but I don't believe in jump grids for a number of reasons (not there originally, externally carried craft, drop tanks, turrets, no damage, etc.). And yes, if you wanted to open up the entire cargo bay (empty of course) of a Subbie I would allow it to perform as a 200ton ship.

As for recovery ops being done by something else, well again the original description states they do. And doing that if restricted to J1 makes zero sense to me.

 

[Icosahedron]

And to use rules for odd configurations, I could design a 400dt closed structure that looks like an X-boat Tender with open doors, fit a 20 dt Jump Drive (MT/TNE) and she'll be capable of J-4.

Which just goes to show that the rules are not infallible.

The rules were designed for a purpose. You are obviously intent on circumventing that original purpose. Whether you label that intent 'innovation' or 'cheating' depends on your POV. It's YTU and you can do what you want, but it's pretty obvious to me that your 'innovation' wasn't intended to exist by the rule writers.

The rules are a can of worms, but they suggest to me that if you want your ship to work in that way, you should design it as a 'rig' that clamps onto an externally mounted X-boat to form a dispersed structure. If you have it enclosing the X-boat as a potentially streamlined shape, then it retains its full volume regardless of whether the doors are fully closed, or opened by a 2mm crack...

If you're getting into topology as a solution, all you really need is a tiny vent-hole somewhere...

 

[far-trader]

If you have it enclosing the X-boat as a potentially streamlined shape...

For what it's worth, description of the shape and illustration aside, the X-Boat Tender is an unstreamlined hull.

 

[BytePro]

For a Subbie that would both involve a no-cargo run, and having to reinforce the cargo bay wall to prevent jumpspace intrusions. There's also the question of how big an entry into an open space in a ship would be needed to alter the ship's displacement. Whilst I'm not sure about other ships - the Tender's doors take up one whole side of the hangar bay and some of the two adjacent sides, which I think would lower displacement.

A no-cargo run would still allow jumping 2 or 3 parsecs with a load of passengers when strategically economically sound to do so, overcoming the need to limit routes to J-1.

The 'reinforce the cargo bay' thing is personal assumption - a cargo bay is quite structurally sound IMTU - especially as it has doors.

The question of 'how big' a displacement change has to be is only relevant if one is applying design rules in this fashion. Displacement is an abstract design element - it makes RW design easier, hence the official +/- X% deckplan rulings and the 100 ton increments.

I wouldn't call my suggestion metagaming, it all revolves around the face that jump drives are limited by hull displacement - and displacement is the volume *enclosed* by the hull.

That *fact* only exists in the design rules.

The range of a jump drive is not described in game as limited by the volume of a ship, but rather its designed rating, computer model and fuel.

The hull displacement thing is an artifact of the rules - demonstrated by the use of increments of 100 tons for non-capital ships.

Hence metagaming as a description - not meant as an insult. It is taking the rules as written and interpreting them in such a way as to change the ingame balance of things. Which is exactly what this does as demonstrated by the example of the Subsidized Merchant.

I've made such designs myself - its an obvious opening in the rules for anyone looking to min/max design rules. Since drop tanks are specifically spelled out in the rules, the absence of any explicit rule countering this use, and the no cost advantage to using this which would also unbalance setting assumptions, indicates that this is an unintended loophole.

 

[rancke]

A no-cargo run would still allow jumping 2 or 3 parsecs with a load of passengers when strategically economically sound to do so, overcoming the need to limit routes to J-1.

Indeed it would. So when all the available evidence shows that ships generally are not used that way, we have to conclude that there are reasons why they aren't designed to do so. Reasons that may or may not be too subtle to show up at the level of detail that the ship design systems encompass, but are there anyway.

We can thus conclude that this is not a viable strategy and that X-boat tenders can't do it.


Hans

 

[mike wightman]

Or we could assume that it is so common it's not worth mentioning explicitly

 

[rancke]

Or we could assume that it is so common it's not worth mentioning explicitly

And yet not common enough to be mentioned in the rules as an available option? Riiiiiight!


Hans

 

[mike wightman]

Ahh, but the rules as written allow it.

It's the setting that makes no mention because it is so commonplace =)

 

[far-trader]

...So when all the available evidence shows that ships generally are not used that way...

What evidence would that be exactly? The lack of specific direction that it is?

We have drop tanks on the Gazelle showing a similar function.

We have the Jump Ship with its variable performance and externally carried sling cargo capacity.

We have the Vargr Corsair with its clamshell doors and 100tons of cargo that is said to jump away with captured ships whole with no mention of configuration (are we to presume they only take ships that fit? or do they use the capacity and larger drives to secure a variety of ships and tonnages, seems a poor design to be using if all you can steal are small craft and 100ton ships that will fit in the cargo hold).

...I suspect there are more I'm forgetting. Are there any where your contention is backed? A specific mention that says you can't carry externally or that performance is fixed to hull?

...we have to conclude that there are reasons why they aren't designed to do so. Reasons that may or may not be too subtle to show up at the level of detail that the ship design systems encompass, but are there anyway.

Sure, that's reasonable for the bulk of cases. Not for all cases. Not the exceptions such as the X-Boat Tender. Military ships in general even. Civilian ships unlikely so unless specifically designed so (like the Jump Ship)

We can thus conclude that this is not a viable strategy and that X-boat tenders can't do it.

Or we can conclude that the facts of the case, the extra drive capacity, is actually there for a reason. For that very reason. That it is not only viable but logically reasonable.

Why else (I'm interested in your opinions) have the Type H drives when Type E* would do? Saving considerable tonnage and cost. Or even no drives? Saving even more. All the tender really needs is a small tug to bring the X-Boats to it and solar panels to provide the power for the life support. Well, except for that bit about it being the ship used for returning X-Boats that have gone astray. Which I'll say again J1 just won't do for.

* or Type F if the reason is some damage soak capacity in case of attack, and still a whopping huge savings

 

[rancke]

What evidence would that be exactly? The lack of specific direction that it is?

We have drop tanks on the Gazelle showing a similar function.

How do you figure that? Drop tanks are specifically designed to be external to the main hull. The X-boat tenders have a 1000T hull.

We have the Jump Ship with its variable performance and externally carried sling cargo capacity.

See above.

We have the Vargr Corsair with its clamshell doors and 100tons of cargo that is said to jump away with captured ships whole with no mention of configuration (are we to presume they only take ships that fit? or do they use the capacity and larger drives to secure a variety of ships and tonnages, seems a poor design to be using if all you can steal are small craft and 100ton ships that will fit in the cargo hold).

Yes, of course we are to presume that they only take ships that fit. Otherwise the clamshell doors have no function whatsoever.

...I suspect there are more I'm forgetting. Are there any where your contention is backed? A specific mention that says you can't carry externally or that performance is fixed to hull?

There's the first chapter of the Psionic Knights adventure that describes the major undertaking it is to mate two ships to allow them to jump together. Now let me ask you, are there any rules that allow you to do so without a jump net?

Or we can conclude that the facts of the case, the extra drive capacity, is actually there for a reason. For that very reason. That it is not only viable but logically reasonable.

Or we can conclude that the design is faulty. If it was deliberately designed to allow jump-4 performance, it is exceedingly odd that it isn't mentioned prominently in the design notes. I'm right when I assume it isn't mentioned in the design notes?

Why else (I'm interested in your opinions) have the Type H drives when Type E* would do? Saving considerable tonnage and cost. Or even no drives? Saving even more. All the tender really needs is a small tug to bring the X-Boats to it and solar panels to provide the power for the life support. Well, except for that bit about it being the ship used for returning X-Boats that have gone astray. Which I'll say again J1 just won't do for.

There's my theory that the X-boat Service turned into a huge boondoggle long ago. Odd and inefficient designs that costs more than necessary seem to fit right into that notion.


Hans

 

[shield]

You want your tender to have an enclosed hanger for repairs - hell of a lot easier when you are pressurised. We know the tender carrys spares as cargo and had a workshop. The description of the tender says they also use it to carry xboats from world to world - transport not rescue and salvage.

The current design allows for all that.

Given that they have armed the tender, the extra drive letters do allow the ship to take some damage and still be able to move. With Drive E, 1 hit and you stop moving

And as for the quote that 3 turrets seemed a bit light for a military vessel - This is the IISS not the navy, the default Type S comes with no weapons, the survey scout is also unarmed.

 

[shield]

I don't think you would use a tender for rescue and recovery anyway. You can't jump your operational tender away - its too busy sending and receiving data, fueling X boats, doing minor maint and allowing the half-crazed X-boat pilot to talk to someone besides the computer. If you jump away on a resuce mission you disrupt the communication chain. You also strand every incoming X-Boat. Canon says these things only have limited duration and a pilot typically only has about 4 days L/S after jump. If the tender is not there, then thats a dead pilot. I know scout service life has its dangers but thats a bit excessive even for the scouts.

So a X-Boat arrives somewhere off the route. All it can do is issue a SOS. If it is in a world with a good starport, a base, or a decent population and TL, some sort of rescue boat should arrive and pick up the pilot before he dies. He gets back to the IISS either by hitching a lift on a passing Imperial vessel, or uses some sort of Imperial passage voucher system and a commercial vessel.

As for the xboat itself, it would be towed into a holding orbit in a system with decent facilities, It can then be picked up by a passing Imp vessel with sufficient cargo space, shipped freight by normal transports. Only if one of these is unavailable would the IISS have to send a salvage vessel (crewman is either dead or rescued).

If the world is E port and TL5, the xboat pilot is dead, word will get back to the IISS by passing tramp trader, and then they would send out a salvage vessel. Who is going to steal an X-boat. It makes a crap pirate vessel. Only thing of value is the computers (assuming the JD is broken otherwise no misjump)

Given it is likely to be in backwater systems, the salvage vessel is probably J2, with space for extra fuel, big hanger for the salvaged vessel (- it allows repairs in a short sleeve environment and during jump) and probably TL11. Enough for J2, but common enought to be purchased and built locally. No need for a J4 4G ship, its too over specified, like using a battleship on customs duty.

 

[McPerth]

Another thing to take into account is how a hole as large as open clamshell doors in the jump envelope would affect the jump.

IIRC I readed (I think in the Q&A in a TD or MTJ, I don't find now the exact reference, sorry), as an explanation about the lack of jump hits on external explosion table (the reasoning of the question was that if the jump gird on the hull is what allows you to jump, a hole on it could lead to reduced jump capability or missjump), that a ship may jump with a hole in its jump envelope about a metter or two in diameter. The clampshell doors we're talking about are quite larger than this, so will be the hole.

As I understand canon (as always, I may well be wrong or misunderstand it), it's clear that adding tonnage (either with the jump net in the Jump Ship case, containers in the Modular Freighter, barges in the MT jump frame, drop tanks, etc) lowers jump (and maneover) performance, but only in the case of the Gazelle seems to hint the reverse is also true.

As I told before, the Gazelle is a controversial design. If you class it as 400 dton, then it hints you can raise your jump and maneover performance by lowering the tonnage (but even in this case, it's by dropping the excess tonnage, not just oppening it to space). Even so it's rated as 300 dton, so it seems to be the first case (lowering performance by adding tonnage), even if it has 4 hardpoints (as if rated 400 dton). I'm affraid I have no answer to this dilemma.

In any case, I think that oppening clampshell dors shouldn't reduce tonnage, and so shpouldn't increase performance, and even may unstabilize your jump envelope, leading to missjump.

To reduce your tonnage to allow this performance increase (if possible at all, as I said there are, AKAIK, no cannon examples nor refferences), you should drop the excess tonnage, not just open it to space.

So, to allow your tender to do so, you must redesign it as an dispersed structure design with J4 drives, with the possiblity to attach Xboats (as a battle tender does with BRs) up to 1000 tones (reducing performance to J1).

AFAIK, a J4 BT displacing 300 kdton of with 100 kdton are tenders has not its jump capability increased to J6 when not carring its BRs, even if its jump drives and fuel would be enough to achieve that for a 200 kdton ship. and in this case, computer would not be a problem, as most military ships carry maximum computer for their TL.

Perhaps it could if you design it as a 200 kdton J6 ship (dispersed structure) with capability to attach up to 100 kdton of BRs, reducing accordingly its jump capability to J4, but it won't be the cse of opening clampshells either.

Not sure if this is cheating the system, only another way to describe the same ship, or a rules paradox. I leave that to anyone's oppinion.

 

[far-trader]

The description of the tender says they also use it to carry xboats from world to world - transport not rescue and salvage.

Not quite:

Supp 7:

"They also undertake recovery missions to pick up damaged xboats or boats which have misjumped to off-route systems."

Can't be much clearer that they also do rescue and salvage.

Given that they have armed the tender, the extra drive letters do allow the ship to take some damage and still be able to move. With Drive E, 1 hit and you stop moving.

And as I noted Drive F would be enough. It's not like these are ships of the line expected to fight pitched battles. They just need enough discouragement to keep desperate small ships from attacking. The turrets is plenty for that. And a single drive letter buffer is lots. So why go all the way to H?

And as for the quote that 3 turrets seemed a bit light for a military vessel...

Seems a bit light for a 1000ton military ship was my point. Not for a 400ton military ship. The type S comes standard with a double turret, weaponry specific to mission seems the intent. Not unarmed as the default. As for the Survey Scout it is specifically designated as unarmed for a reason. Not that I agree with the idea for the Imperium. It clashes with the rest of canon. And even so it does have 4 hardpoints and notes that it can be armed if necessary.

 

[rancke]

Supp 7:

"They also undertake recovery missions to pick up damaged xboats or boats which have misjumped to off-route systems."

Can't be much clearer that they also do rescue and salvage.

I'll grant you that, but it could make a whole lot more sense. Your extra X-boat tender is informed of a stranded X-boat four parsecs away in the middle of nowhere. So it opens its hangar doors and jump out to fetch it. Having collected the X-boat, it closes its hangar doors and looks around for 400T of fuel lying around to enable it to make four one parsec jumps back home.

Umm...

All I can say is that considering the X-boat tenders used to fetch stranded X-boats have to be over and above those used as tenders, I would contract for a few dedicated transports for those jobs instead.

And as I noted Drive F would be enough. It's not like these are ships of the line expected to fight pitched battles. They just need enough discouragement to keep desperate small ships from attacking. The turrets is plenty for that. And a single drive letter buffer is lots. So why go all the way to H?

To increase the cost and inflate the budget, putting some nice graft in somebody's pockets.


Hans

 

[far-trader]

I'll grant you that, but it could make a whole lot more sense. Your extra X-boat tender is informed of a stranded X-boat four parsecs away in the middle of nowhere. So it opens its hangar doors and jump out to fetch it. Having collected the X-boat, it closes its hangar doors and looks around for 400T of fuel lying around to enable it to make four one parsec jumps back home.

Umm...

Well I imagine the fetch and retrieve would come after the search and locate (done by Type S imtu) so you'd already have some additional resources on scene. And the tender would probably be using drop tanks on the way out and carrying some bladders. If they can't fix the X-Boat in-situ to enable it to jump back by itself then the return trip is going to be slow, relying on Type S escorts for fueling along the way.

All I can say is that considering the X-boat tenders used to fetch stranded X-boats have to be over and above those used as tenders, I would contract for a few dedicated transports for those jobs instead.

Quite but the Imperium disagrees with you. More of your graft and influence I suppose I prefer the alternate explanation (designed to extra utility performance), but imo both work. I also have to question any need at all. Given the maintenance and fuel pampering I don't see X-Boats misjumping or breaking down, and so no need for the whole search and rescue. If one goes missing it's a case of theft or sabotage and the IN's job to sort out.

 

[BytePro]

Ahh, but the rules as written allow it.

Sure, the design rules don't explicitly rule out up-ranging a drive when ship dtons is reduced, but operationally, it is not written in the rules to allow it. However, for drop tanks and the like, rules are explicitly written for design and operations allowing them and under what game balancing circumstances.

So the rules as written don't allow it - they just don't expressly disallow it - not the same thing. Don't recall a rule that said anything not disallowed is defacto allowed.

...It's the setting that makes no mention because it is so commonplace =)

And yet not used as otherwise Jump routes would be longer and more connected, which they don't appear to be. So the setting doesn't support the theory of too common to mention.

Regards the unused drive letters - over engineered can be a good idea for certain roles - as supported by the combat and maintenance game mechanics. Getting stranded because of a marginally spec'ed drive could be, er, annoying. One might have to call on a Tender - er - somehow?