All Warships Should Have Drop Tanks

[Theophilus]

Here's a thought that has been rattling around in my head. All warships should be fitted for the use of drop tanks.

This seems to make sense to me. Since any ship that jumps arrives with empty fuel tanks and is then stuck until refuelling can occur a quick escape is impossible. Now if all warships were fitted for drop tanks, then they could arrive insystem with a full fuel load, and thus escape if necessary, without taking time to refuel.

While use of drop tanks would not be manditory, there strategic use's makes them almost assured. Imagine your AHL jumping insystem, Jump 10 in less time whithout the time to refuel, Jump in, hit your target jump out.

Also, Fuel tankers MUST be drop tank equipped. Otherwise, they couldn't follow the fleet with any usable amount of fuel, Since Imperial standard is Jump 4 and a tanker that uses 44% of it's tonnage for it's own jump and another 2% for bridge, 3% for maneuver, 5% for Pn and fuel, etc not to mention crew etc. Jumps with the fleet, empty tanks, Fleet retreats, Tanker Dies.
Or that million ton drop tank using Tanker, jumps with the fleet, refuels those 100kton battleships, Jumps out, Tanker saved.

Any thoughts?

 

[far-trader]

I've thought the same at times. And have designed and retrofitted many drop-tank ships.

I've even made a tender that used drop tanks. Not the way you're saying (which for some reason I don't recall thinking of) but for the ships being fueled. Tender jumps in, drops full tanks, fleet elements grab their tanks and are ready to jump again. Tender can collect empties or jump out at reduced tonnage.

One thing I'd note as a possible issue is the transfer time. Maybe there's an upper limit to how much fuel a drop tank(s) can fast deliver, limiting the maximum size of ships/jumps to something that makes capital ships with drop tanks not so workable. Like they can only manage low J (or none beyond a certain tonnage).

Of course I make drop tank use more prone to causing misjumps, which you don't want to do routinely. For some ships, in some situations, sure. But maybe not your flag ships.

 

[Spinward Scout]

A good idea, but impractical on the larger vessels, I would think. A Drop Tank can interfere with a Jump by it's gravity disturbance. If a large drop tank doesn't get enough distance from the ship, it can cause a misJump. On a small ship, a Drop Tank can maneuver away quickly enough to not disturb the Jump. Not sure if that is in all versions or if it's canon.

 

[rancke]

Here's a thought that has been rattling around in my head. All warships should be fitted for the use of drop tanks.

This seems to make sense to me. Since any ship that jumps arrives with empty fuel tanks and is then stuck until refuelling can occur a quick escape is impossible. Now if all warships were fitted for drop tanks, then they could arrive insystem with a full fuel load, and thus escape if necessary, without taking time to refuel.

Several reasons why a warship might not be fitted for drop tanks.

* The requisite technology was only invented around 1080. Any ship built before that won't have the fittings. (Retrofitting may or may not be possible, depending on the shape of each ship class).

* Drop tanks cost money to buy and money to replace.

* Spare drop tanks requires big freighters to move about, so they represent an additional logistic problem. And lets not forget that differently sized (and differently shaped) ships will each require its own class of drop tanks.

While use of drop tanks would not be manditory, there strategic use's makes them almost assured. Imagine your AHL jumping insystem, Jump 10 in less time whithout the time to refuel, Jump in, hit your target jump out.

A jump-4 capable fleet can jump 1, 2 or 3 parsecs and arrive with enough fuel to jump out again.

Also, Fuel tankers MUST be drop tank equipped. Otherwise, they couldn't follow the fleet with any usable amount of fuel, Since Imperial standard is Jump 4 and a tanker that uses 44% of it's tonnage for it's own jump and another 2% for bridge, 3% for maneuver, 5% for Pn and fuel, etc not to mention crew etc. Jumps with the fleet, empty tanks, Fleet retreats, Tanker Dies.
Or that million ton drop tank using Tanker, jumps with the fleet, refuels those 100kton battleships, Jumps out, Tanker saved.

Don't take the tankers into harm's way. Jump to some place witin one parsec of target system, top up warship tanks, the warships jumps and arrives with 3/4 full tanks; meanwhile the tankers make their way back to base or to a rendevouz.


Hans

 

[Mithras]

In response to Hans, I think the idea is a sound one, but would work best in an ATU, where ships can be designed that way (to share drop tank compatibility). When designing military ships a few months ago I came to the similar conclusion that they require fuel to go in, and fuel to get out. In MTU my starships are more like aircraft, with deep penetration strike craft which jump into a system, hit a station or strike at enemy bases from orbit, then jump out back to base. Drop tanks look feasible for this kind of warfare.

Of course you only use them in actual combat, or combat-training, not regular peacetime duties.

I might play around with the idea myself...

 

[Theophilus]

A jump-4 capable fleet can jump 1, 2 or 3 parsecs and arrive with enough fuel to jump out again.


Don't take the tankers into harm's way. Jump to some place witin one parsec of target system, top up warship tanks, the warships jumps and arrives with 3/4 full tanks; meanwhile the tankers make their way back to base or to a rendevouz.


Hans

Depending on the version of Traveller you use. Some require all fuel be used in a jump. Meaning a jump 4 ship that only jumps 1, still uses all fuel.

Lets assume you are correct. My jump 4 fleet only jumps three. I can jump out 1, My tankers still have to jump 2 parsecs into possibly empty space, find my fleet and refuel. Whereas using drop tanks still allows me to jump three and have full tanks for the jump back. A strategic and tactical advantage in my book.

A good idea, but impractical on the larger vessels, I would think. A Drop Tank can interfere with a Jump by it's gravity disturbance. If a large drop tank doesn't get enough distance from the ship, it can cause a misJump. On a small ship, a Drop Tank can maneuver away quickly enough to not disturb the Jump. Not sure if that is in all versions or if it's canon.

How, empty drop tanks would be miniscule, compared to the ship using the tank. using CT a 100kton ship jump4, would need a drop tank of 40,000 tons fuel, How much does a shell of that size weigh? How much gravity would a rubber bag of that volume create? I've never seen this "interference" rule in CT, MT, or TNE.
Also, the tank as a percentage of the ship should be the same, ie. jump 4 requires the same percentage of fuel no matter what size the ship is. So small ships have no advantage over larger ships.

Several reasons why a warship might not be fitted for drop tanks.

* The requisite technology was only invented around 1080. Any ship built before that won't have the fittings. (Retrofitting may or may not be possible, depending on the shape of each ship class).

* Drop tanks cost money to buy and money to replace.

* Spare drop tanks requires big freighters to move about, so they represent an additional logistic problem. And lets not forget that differently sized (and differently shaped) ships will each require its own class of drop tanks.

Invented in 1080? Canon where?

Money to buy and replace, yes, but still cheaper than warships, which if they can escape from a tactically unsound situation faster, should outweight the cost issue. It's cheaper to build drop tanks for the fleet than to build one BB.

Freighters, yes. Different size and shape? Maybe, if they are carried through Jump. But if they are collapsable drop tanks, and are only provide the fuel then maybe not. That is, since the tank need not be carried, it only has to provide the required amount of fuel, a 10kton tank could provide fuel for any ship using 10kton of fuel or less, so It May fit my 10,000 ton destroyer, my 30kton cruiser or my 100kton BB, so long as it provides the needed amount of fuel and is dropped before jump.

 

[rancke]

Depending on the version of Traveller you use. Some require all fuel be used in a jump. Meaning a jump 4 ship that only jumps 1, still uses all fuel.

In the very first version of the rules, jump governors weren't mentioned. That doesn't mean they didn't exist, just that the rules didn't mention them. Jump governors have been either explicitly mentioned or implicitly assumed in every subsequent version. I'm going to go along with the majority.

Lets assume you are correct. My jump 4 fleet only jumps three. I can jump out 1, My tankers still have to jump 2 parsecs into possibly empty space, find my fleet and refuel. Whereas using drop tanks still allows me to jump three and have full tanks for the jump back. A strategic and tactical advantage in my book.

Of course it's an advantage. The question is, do you need such an advantage often enough to make the investment and the added operating costs worth it?

Invented in 1080? Canon where?

I said around 1080. Exact date is unclear.

097-1105 Regina/Regina (0310-A788899-A)
[...]

L-Hyd drop ships have only been in service for the last dozen years in the interior, being made possible by recent advances in the field of capacitor engineering, a joint press release explained.

"A dozen years" before 1105 could be around 1090. Allow a decade for the invention to go from prototype to finished. That brings us to around 1080. Various assumptions could push the date back or forth a bit.

Money to buy and replace, yes, but still cheaper than warships, which if they can escape from a tactically unsound situation faster, should outweight the cost issue. It's cheaper to build drop tanks for the fleet than to build one BB.

How do you plan to use the drop tanks? The way the Gazelles carry them around and only use them in an emergency? You've just increased the operating expenses of the entire fleet by making them use more fuel for each jump. Do the ships carry a full load of fuel inside as well as a full load in the drop tanks[*]? That reduces the routine performance of their drives, since jump-4 drives can only perform jump-3 if carrying 40% extra. Or do you plan to have them use the drop tanks routinely? That increases the logistical load considerably.

[*]The Gazelles are reduced to jump-2 without their drop tanks. Or is it jump-1? Internal tankage is 81T, but there's that pesky fuel-hogging power plant. OTOH, its volume is down to 300T without the drop tanks, so I guess jump-2 works.​

Do you armor your drop tanks to match the armor on the ships? That increases their cost. If you don't, the ships become very vulnerable to fuel hits.

Freighters, yes. Different size and shape? Maybe, if they are carried through Jump. But if they are collapsable drop tanks, and are only provide the fuel then maybe not. That is, since the tank need not be carried, it only has to provide the required amount of fuel, a 10kton tank could provide fuel for any ship using 10kton of fuel or less, so It May fit my 10,000 ton destroyer, my 30kton cruiser or my 100kton BB, so long as it provides the needed amount of fuel and is dropped before jump.

According to the rules, drop tanks aren't collapsible and they're one-use. (Personally, I think that it should be possible to retrieve and reuse them, but that will also require extra effort).

So you're not going to have the ships carry their drop tanks along with them? Lot's of extra freighting around it is, then.


Hans

 

[HG_B]

Depending on the version of Traveller you use. Some require all fuel be used in a jump. Meaning a jump 4 ship that only jumps 1, still uses all fuel.

Unless of course you shut the valves to the other fuel tanks. Then, you only use the fuel in the tank that is feeding the fuel.

 

[rancke]

Unless of course you shut the valves to the other fuel tanks. Then, you only use the fuel in the tank that is feeding the fuel.

Then you don't jump. It costs 40% of volume fuel to enter jump-4 space, no matter if you jump a meter or four parsecs. And without a jump governor, a jump-4 engine can only put you into jump-4 space. However, with a jump governor, it can put you into jump-1 space, jump-2 space, and jump-3 space too. And a jump governor is dirt cheap.


Hans

 

[HG_B]

Then you don't jump. It costs 40% of volume fuel to enter jump-4 space, no matter if you jump a meter or four parsecs. And without a jump governor, a jump-4 engine can only put you into jump-4 space. However, with a jump governor, it can put you into jump-1 space, jump-2 space, and jump-3 space too. And a jump governor is dirt cheap.


Hans

Reread. I'm wasn't referring to doing a J4... o:

 

[rancke]

Reread. I'm wasn't referring to doing a J4... o:

Reread. I was talking about using a jump-4 drive to do a less-than-J4 jump.


Hans

 

[HG_B]

Reread. I was talking about using a jump-4 drive to do a less-than-J4 jump.


Hans

Book 2: "Jump fuel under the formula (0.1 MJn) allows one jump of the
stated level. Ships performing jumps less than their maximum capacity consume
fuel at a lower level based on the jump number used."

 

[rancke]

Book 2: "Jump fuel under the formula (0.1 MJn) allows one jump of the stated level. Ships performing jumps less than their maximum capacity consume fuel at a lower level based on the jump number used."

That's after the introduction of the jump governor. In which case you've no need to seal off part of your fuel tanks to avoid using the full load of fuel, making your original suggestion moot.


Hans

 

[HG_B]

That's after the introduction of the jump governor.

Really? Jump governor isn't listed in the book I just quoted. Which book (before LBB2) was that in?

 

[rancke]

Really? Jump governor isn't listed in the book I just quoted. Which book (before LBB2) was that in?

Book 2, 1st edition.


Hans

 

[far-trader]

For clarity of the discussion re Jump Governors and Jump Fuel use:

The first printing of CT LBB2 is where one finds the rules saying that all fuel is used in a jump regardless of the distance jumped. A ship with J4 drives is capable of J1, J2, J3 or J4 but will always use the full fuel calculated to fire up a J4 drive, that is 40% of the ship volume. As far as I recall there is no mention of a Jump Governor in LBB2 1st printing.

This rule was dropped in the second printing of the CT LBB2 rules, and as far as I recall never revisited. Except briefly...

In the first printing of CT LBB5 (HG) there was a device available, called a Jump Governor, that could be retrofitted to LBB2 designs. It was cheap and took up just 1ton. It allowed you to ignore the original rule about fuel use and meant no matter what jump drive you had you only used the amount of fuel required for the actual jump. The rules in that book also stated that all ships designed with HG had a Jump Governor built into the Jump Drive at no extra cost or volume. The second printing of HG dropped all reference to the Jump Governor to match the second printing of LBB2.

CT (revised, if you will) does not need a Jump Governor (or it is included in all Jump Drives) and a jump only uses enough fuel to make the actual jump.

 

[HG_B]

Book 2, 1st edition.


Hans

I have a 1st Ed LBB2. Nothing about a Jump governor.

 

[mike wightman]

The jump governor was introduced in HG 1st edition, TL10 - under 1st edition LBB2 rules a ship consumes all its jump fuel regardless of the distance jumped.

1st edition HG also introduced drop tanks, TL12.

 

[The Oz]

IMTU I allow purpose-built fuel tankers to be used as "mobile" L-Hyd tanks. The tankers are equipped with very long, high-capacity fuel lines that allow other ships to draw jump fuel from the tanker to power up the J-drive, then the fuel lines are disconnected and withdrawn to a safe distance and the ships jump away. The tanker can then refuel and jump to the destination to support the fleet there.

This way you don't have the logistical or design problems of either resupplying drop tanks or armoring drop tanks, nor do you have to worry about the drop tanks only fitting one particular class of ship.

 

[rancke]

IMTU I allow purpose-built fuel tankers to be used as "mobile" L-Hyd tanks. The tankers are equipped with very long, high-capacity fuel lines that allow other ships to draw jump fuel from the tanker to power up the J-drive, then the fuel lines are disconnected and withdrawn to a safe distance and the ships jump away. The tanker can then refuel and jump to the destination to support the fleet there.

This way you don't have the logistical or design problems of either resupplying drop tanks or armoring drop tanks, nor do you have to worry about the drop tanks only fitting one particular class of ship.

Not quite. You also have the problem of explaining why the same setup won't work for civilian freighters. Park one of these babies at the jump limit of each world, and your freighters can devote almost all their internal volume to cargo. That improves the economics of freighting immensely, especially for high-jump traffic.


Hans