Drop Tanks and Hard Points

[Hal]

Hello Folks,
Just out of curiosity, in YOUR Traveller Universe, how do you handle the situation outlined below...

You've a 300 dton hull, with an additional 100 dtons worth of capacity utilized as drop tanks, which are attached to some location aboard the primary 300 dton hull.

In your opinion, should the ship be able to utilize hard points at the location where the 100 dton drop tank addition is added to the primary hull?

If the answer to the above question is no, would it make sense of sorts, to specify that the region the drop tank is attached to, actually COSTS hard points in order to have that region "Free of hardpoints for the attachments"?

Just musing aloud...

 

[far-trader]

The rules (in HG/TCS) are clear that drop tanks don't cost hardpoints or add hardpoints (the tonnage is not used for calculation of hardpoints). Despite this we have the 300ton Close Escort with 4 hardpoints and 100tons of drop tanks messing up reality

In MTU:

I've played with not only drop tanks costing hardpoints for that reason but externally carried craft as well. This rationalized the half hardpoints on the CT ships with externally carried craft* (the Subsidized Merchant and Liner, the Yacht, the Lab Ship) while those with internally carried craft (the Safari Ship, the Patrol Cruiser, the Mercenary Cruiser) retained full hardpoint allotments. My basic rule was externally carried craft or drop tanks result in loss of half the allowable hardpoints.

* and along came that darned Close Escort with it's externally carried gig to mess that up as well

But I typically "build" the Close Escort as a 400ton hull (so 4 hardpoints, bridge calculated for 400tons, etc) with 100tons of carried drop tanks to correct the mistake. With the tanks dropped it drops to 300tons of course for better performance.

I think all drop tank using ships should be built that the hull tonnage includes the drop tanks. Otherwise they are just too cheap (cost and bridge requirements).

 

[Hal]

Agreed, the externally fitted carried craft along with the bridge sizes for the ships with drop tanks are an issue.

Part of the problem however, is that CT is volume oriented, while the issue stems from that of a surface area issue. One possible fix to this is that for every full increment of 100 dtons of added "drop tanks and/or hull surface carried subcraft", the ship loses 1 hard point.

Thus, in the example given with the Gazelle class ship, if it carried a 100 dton drop tank, and carried a 50 dton subcraft, the Gazelle would lose 1 hard point - one for the drop tank, but zero for the 50 dton subcraft. However, were the ship to have had a 150 dton drop tank plus a 50 dton subcraft, such a ship would lose 2 hard points.

One thing I mentioned on the CT STARSHIPS mailing list (I sent a question on this to that list as well) is that just because you have a drop tank on a ship doesn't neccessarily mean you can't design your ship to have a hard point AND a turret in place where the drop tank joins with the main ship's hull. What would happen in that instance would be that the drop tank covers the existing turret so as to render it unusable while the drop tank is joined with the hull. My suggested "fix" to this concept is that the drop tank has to account for that "hollow" needed to cover the turret while it joins with the main ship. Thus, if you had a 300 dton hull with a need for 90 dtons of fuel in the drop tank, the new drop tank size would be:

90 for the fuel
3 for the turret hollow

Total 93 dtons.

Now, our 300 dton ship with a 93 dton drop tank, could have 2 turrets showing, one hidden, and carry an extra 90 dtons of fuel where needed for extended range jumps.

As for the Bridge costs? I agree. The bridge should be rated at the combined hull size rather than just the original hull size sans drop tank. The reason I'd go with that line of thought is that the extra "cost" of the bridge is that it contains all those extra pieces of equipment required to insure that the drop tank drops properly and clears away from the hull as it enters into jump space.

There is another "issue" that comes into play however <evil grin>

Does another ship's hull come into play when it comes to the requirement of "planetary diameters distant" for the jumping ship? A 100 dton drop tank is 25% of the volume of a combined 400 dton hull, or 33% of the remaining drop-tank less hull. How close can that drop tank be before it poses issues with jumping? <sigh>

One could almost wish that the use of a drop tank automatically incurs a +1 penalty to the Mis-jump roll. Military ships with their +1 bonus for Misjumps would be safe, but civilian craft would have as much risk using a drop tank as they would with unrefined fuel. In fact, using a drop tank with unrefined fuel is generally considered to be an unacceptable risk (were the +1 penalty to jumps a viable houserule).

 

[mike wightman]

My house rules for this are that the drop tanks use 1 hardpoint from the 3 that the 300 t hull grants.

The reason that the Gazelle can have those two barbettes in addition is my house rule that barbettes are 5t turret equivallents. You can have one barbette per hardpoint used for a normal turret.

So IMTU a scout/courier could have one turret and one barbette, a 200t trader could have 2 turrets and 2 barbettes. A 400t patrol cruiser could have 4 turrets and 4 barbettes.

Reason being you can always add an extra 'turret' by carrying a 10t fighter - so why not just allow the 5t cost for an extra turret.

 

[robject]

Hello Folks,
Just out of curiosity, in YOUR Traveller Universe, how do you handle the situation outlined below...

You've a 300 dton hull, with an additional 100 dtons worth of capacity utilized as drop tanks, which are attached to some location aboard the primary 300 dton hull.

In your opinion, should the ship be able to utilize hard points at the location where the 100 dton drop tank addition is added to the primary hull?

If the answer to the above question is no, would it make sense of sorts, to specify that the region the drop tank is attached to, actually COSTS hard points in order to have that region "Free of hardpoints for the attachments"?

Just musing aloud...

In T5: no to the first question, and to the second: drop tanks in T5 are more or less similar to attached smallcraft.

 

[far-trader]

Part of the problem however, is that CT is volume oriented, while the issue stems from that of a surface area issue.

Quite. Part of the idea of losing hardpoints for externally carried craft and drop tanks is to address that in a way. The hardpoint per 100tons rule is an abstraction of surface area and such I think. I also toyed around with making it volume dependent (and I think I used the same 100ton per rule you outlined, it's a natural given the system). But then we're applying an arbitrary volume limit to fix a surface area one. For example I think a 40ton Pinnace (with those wings) would have more surface area impact on a ship than 100tons of compact drop tank.

As for the Bridge costs? I agree. The bridge should be rated at the combined hull size rather than just the original hull size sans drop tank. The reason I'd go with that line of thought is that the extra "cost" of the bridge is that it contains all those extra pieces of equipment required to insure that the drop tank drops properly and clears away from the hull as it enters into jump space.

Yep, and that the ship can be properly maneuvered in real space with them attached as well.

There is another "issue" that comes into play however <evil grin>

Does another ship's hull come into play when it comes to the requirement of "planetary diameters distant" for the jumping ship?

By CT rules I don't think so, I seem to recall it being only large (i.e. planetary and larger masses). But there is mention at some point about jumping from a ship, though I think that was attempted WHILE IN JUMP so it might not apply.

One could almost wish that the use of a drop tank automatically incurs a +1 penalty to the Mis-jump roll...

I do in MTU That's why drop tanks aren't allowed for commercial use in MTU. Not some (lame imo, canon) story about sloppy work or industrial sabotage ruining the first commercial application of centuries if not millennia old technology and killing the idea after one incident.

 

[Hal]

In T5: no to the first question, and to the second: drop tanks in T5 are more or less similar to attached smallcraft.

When my ordered copy of T5 comes in, I'm going to delve into that rather eagerly

 

[Maccat]

Offhand, no there's no hit with the drop tanks on the hardpoints (nor do you get extra! Bad Gazelle!), nor with carried craft. The new MgT has docking clamps and such, which further complicates it.

I've used both combined tow capacity and not for bridge size. Making use of drop tanks require the full hull seems to defeat the whole purpose of them, personally. A major point of their use is to like have a high-g ship that just plain *can't* have the jump fuel be able to jump, especially w/ HG. Also, cheaper than a big hull, there *is* a cost savings. Then again they get shot off if you look wrong at them. Also the new MgT has what looks like good misjump stuff in one of the SRDs for em. Add in things like crossing the J5 rift, also (at a cost) multiple jumps (say 2xJ4) which are otherwise almost impossible to design!

I always wondered if the XBoat tender with it's fuel plant and remote loading fuel thing acted in essence as a drop tank for the XBoats, where when used say it shears the hose and the replacement for that equals the cost of a 40t drop tank, no? <s>

It always struck me that they don't adversly affect the streamlining, you can land/launch, do GG refueling with these things attached (!) *That* leads to some interesting configuration issues, much more than hardpoint stuff.

 

[aldemps]

Hi,
It's been 20+ years since I last played Traveller so I'm a little rusty on the rules, but if a ships displacement is increased from 300T to 400T then wouldn't the jump drive have to be upgraded to generate a jump field to cover all the ship.
I imagine that a J-Drive installed on a 300T ship would be able to generate a field to cover 300-399T, so that the ship in the original post would arrive at it's destination missing 1T (perhaps a hole in it's shiney new drop tank).
As I say its been 20 odd years since playing so forgive me if I have forgotten or missed something obvious.
Back to lurking I go.

 

[boomslang]

Hi,
It's been 20+ years since I last played Traveller so I'm a little rusty on the rules, but if a ships displacement is increased from 300T to 400T then wouldn't the jump drive have to be upgraded to generate a jump field to cover all the ship.

It depends.

For ships build under HG2 and using percentage-of-displacement drives, the change in hull displacement will always effect drive performance, and allowances must be made -- either by installing larger drives at build time, or by accepting decreased performance with the drop tanks attached after building.

For ships designed under B2 (which does not provide for drop tanks; you have to import the rules from HG2), ship drive performance is governed by a table cross-referencing drive letter and a range of hull sizes; for some hull + drop tank configurations, this will move the performance rating to a new column, for others, it won't.

For example, if you build something like the Gazelle under B2 (using Drives-H across the board), when you drop the 100 dtons of drop tanks and reduce the ship's effective displacement to 300 dtons, its drive performance does not change (which makes the drop tanks moot in that scenario; you're better off just going with something like the non-drop-tank Fiery class instead).

OTOH, if you add 100 dtons of aftermarket drop tanks (200 dtons total is the maximum its Drives-A can handle) to a Type S/J, you will knock its drive performance down to level-1 across the board while carrying them... which might provide a useful endurance boost.