Converting a Freighter for combat use

[HalC]

Hello Folks,
If you had to convert a heavy freighter over to escort duty, as a hull that can be modified faster than it can be built at a ship-yard, would you make the effort to do so?

Take for example, a 1,500 dTon hull that has three separate holds, two that are 60 dTons each, and one that is 200 dTons (labeled as Aft, Port, and Starboard holds). It already can carry two fighters plus a pinnace and a fuel skimmer - but you want to beef it up more.

Would you expect that you could simply remove the cargo bay doors for the port and starboard cargo holds, refit it with rudimentary launch facilities for extra fighters, and have the freighter act as its own escort vessel in normal space by launching its own fighters?

Just curious.

Hal

 

[baithammer]

Hangars and Docking spaces take multiple turns / minutes to launch or recover vessels and during this time can't expend thrust or fire weapons by the launching / launched craft. ( Would affect jumping out as you'd need to finish recovery operations.)

Upgrading weapon systems would be a more flexible upgrade and using a seperate escort vessel with better armour for fighter carry would be another alternative / addition.

 

[Subzero001]

If you look to the Elizabeth Moon (Vatta Series) the privateers and the David Weber (Honor Harrington) the Q type ships where she has fighters, missile pods and dreadnought size weapons. For ideas of what should be possible for what your trying to invent for MGT2 Good luck and happy hunting!

 

[HalC]

Hangars and Docking spaces take multiple turns / minutes to launch or recover vessels and during this time can't expend thrust or fire weapons by the launching / launched craft. ( Would affect jumping out as you'd need to finish recovery operations.)

Upgrading weapon systems would be a more flexible upgrade and using a seperate escort vessel with better armour for fighter carry would be another alternative / addition.

For purposes of my campaign, having access to another "separate escort vessel" is not an option. It boils down to fighting with what you have when you have it kind of situation.

A flight hangar area (depending on which version of High Guard for MgT you read, either uses a percentage of the original craft in addition to the size of the craft being carried, or you need 1.3 x the size of the craft being carried, or 2.0x the size of the craft being carried.

So, let's say for the sake of argument, we're going to use two cargo bays for the conversion. Each of them is 60 dTons in capacity, each of them had their own cargo bay doors initially. Converting it over to a hangar would require that 60 dTons can only carry 30 dTons of fighters per bay thus modified.

That in turn provides the ability to launch one fighter per cargo bay per turn per hangar - in addition to the original flight deck that the ship had where it carried 2 fighters, 1 fuel skimmer, and one pinnace.

Going from 2 fighters to 8 fighters upgrades the freighter's capacity to act as an escort type vessel - and it would seem that converting the cargo holds into hangars should be relatively simple - a task that wouldn't require for instance, a shipyard.

 

[Anonymous]

No reason why you can't arm a freighter, but any REAL warship will eat it for lunch. If pirates don't have real warships, it'll be good.

The same argument applies today when someone put puts a missile on a container ship, or a missle boat, instead of on a destroyer, or a cannon on a truck instead of an AFV - in one of the recent arab uprisings (Syria?) they used a lot of cannon trucks with improvised armor which might have been more dangerous to the user than the enemy.

There are many examples from real world weapons you can look at.

First off there "parasite fighters" which were carried externally by bombers to protect themselves.

https://en.wikipedia.org/wiki/Parasite_aircraft

These didn't work as bombers didn't have the payload, the lighter fighters didn't have useful armament, and they eventually got bomber turrets working to the point where fighters didn't want to go near the B-29.

Today the Russians make an anti-ship missile that can be launched from a shipping container. Western special forces can probably do it too but don't talk about it. A large container ship has maybe 400 boxes per row. (edit: But those look like full length containers? if so then 200).

Now in a Traveller ship you'd probably have to fire from the loading door since they don't appear to carry containers strapped to the frame, or externally. In essence this would be how the AC-130 works, where they put cannons in a cargo plane firing sideways.

Then they had the CAM ship which was a merchant with an airplane on a catapult, for convoy protection. They kind of worked but the planes couldn't be recovered. In Traveller you could recover have issues re-arming and repairing your fighters unless you had a full hangar.

https://en.wikipedia.org/wiki/CAM_ship

All these are stopgaps and not particularly effective or efficient.

It's probably cheaper and easier hire a bunch of Travellers to fly escort in some gunboat - but you will have trouble co-ordinating jump arrival times. I'm not sure how the Traveller navy handles that. Seems they'd all arrive piecemeal. You probably jump into the out-system so you have time to form up before anyone reaches you.

edit: Of course, there is the Q-Ship in Traveller; a merchant with concealed turrets to catch pirates.

 

[Condottiere]

There are three options, conversion of an existing freighter, conversion of a freighter during construction, and using commercial standards to design and build a paramilitary ship.

The Peeps designed and purpose built Queue ships for covert operations, Harrington's flotilla was probably converted on the slipways.

The Admiralty subsidized ship construction to add features that would allow militarization of commercial vessels.

Armed merchant cruisers have the potential capability to take on warships, though in Harrington's case her ship probably had an additional plot armour layer, if they can lure them close enough for their light weapons to be fully utilized.

Since our ruleset doesn't permit armour plating after the fact, armed merchant cruisers have an inherent vulnerability, and tend to be suited for roles that place them behind the line of battle, such as amphibious assault ships or escort carriers.

Unless you have your eye on a specific precreated class, backwards engineer what you'd like to have to a freighter that can easily be converted to have those features.

 

[Linwood]

There may be a role for mid-sized freighters (1000 dton or so) converted to SDB carriers for convoy protection or maybe commerce raiding. But you still end up with a very vulnerable civilian ship in the mix.

 

[AndrewW]

Now in a Traveller ship you'd probably have to fire from the loading door since they don't appear to carry containers strapped to the frame, or externally. In essence this would be how the AC-130 works, where they put cannons in a cargo plane firing sideways.

There is the External Cargo Mount.

 

[Garran]

Since you have tonnage to spare, what about installing a small bay weapon (or two) in those cargo door areas and/or swapping out some turrets for barbettes? If you can manage particle ones without the local authorities taking exception, you'd have direct attack options that will out-range most turret-based ships and even at shorter ranges are nasty enough against both ship and crew that typical smaller raiding vessels probably won't want to risk it. If you go with the less intimidating (but less provocative) bay/barbette options you'd still have a powerful enough barrage at long/medium that opportunities would look better elsewhere.

 

[Anonymous]

The problem with q-ships in Traveller is that you can be attacked while transforming into combat form. Everyone knows that you can't be touched while transforming or powering up. It's clearly a rules oversight and needs to be fixed.

 

[Linwood]

Maybe part of the answer is determining at what range an opponent’s sensors could resolve features like pop-up turrets once deployed. Or maybe Stealth could be added to those features to make them harder to sort out.

Expendable panels could be used to hide a fixed mount until it’s ready to fire. If you assume missiles are launched via tubes rather than racks the same might work for them. Maybe venting metallic gases or loose cargo could briefly mask weapon deployment.

It might be allowable to deploy pop-up weaponry on the side opposite your opponent, essentially performing a Pilot maneuver to bring weapons to bear. But since the current rules really don’t worry about ship orientation that doesn’t seem like a good fit. The opponent could always deploy drones to look “behind” their prey to spot something like that.

Irregardless of weapons concealment the single biggest tip-off for an ambush is the sudden energizing of active sensors. But maybe you can fire the first volley with passive sensors only, but I would think that would incur a targeting penalty (maybe only beyond Short Range?)

 

[DickTurpin]

I would need more details on the freighter to make specific recommendations, as well as a better idea of what it's mission would be. Is it strictly an Escort now, an armed freighter, or something in between?

In general terms, assuming that it is to be an escort with no need to retain cargo capacity, would look something like this: increase the M-drive to allow a minimum of thrust 3, 5 or 6 would be best. Convert the large hold into a fighter bay with a launch tube for 10 ton fighters and docking space for nine fighters, or for 8 with a full hangar for repairs. If you want more or larger fighters, leave off the launch tube and just jump into systems further out than normal to allow time to launch a fighter screen before entering space where enemies might be waiting.

The other two holds should be filled with small bay weapons, missiles in one, especially if the ship has thrust 4 or less or the tech available is less than TL 11. The other bay can either be a particle beam for very long range attacks, or a fusion gun bay if the ship has enough thrust to get into medium range.
Scatter a half dozen or so defensive turrets (beam laser or sand, not mixed!) around, and fill out the remainder of the 15 hardpoints with pulse lasers to provide either attack or missile defense as needed.

If you want to really dish out the damage, go with two small missiles bays, add some particle beam barbettes, and reduce the turret numbers to fit the available hardpoints. Avoid small torpedo bays as they will suffer too much attrition from point defense and offer only a small attack DM and damage multiplier.

Happy hunting!

 

[Condottiere]

The record on armed merchant cruisers is mixed, at best.

There's a difference between arming a freighter for self defence and deterrence, and one that is actually expected to seek out and destroy or patrol.

Queue ships won't work against submarine equivalents, because they will prefer to disable or incapacitate the ship from a distance, with a variable chance that they will board the craft to gather supplies or intelligence, compared to surface raider equivalents, which also might just send their equivalent of rubber dinghies.

One thing that freighters do have is space.

 

[Anonymous]

Since our ruleset doesn't permit armour plating after the fact, armed merchant cruisers have an inherent vulnerability, and tend to be suited for roles that place them behind the line of battle, such as amphibious assault ships or escort carriers.

I couldn't find a restriction on retrofitting armor in Mongoose.

 

[Condottiere]

Armour and other parts of the ship integral to the hull (such as configuration or reinforced structure) cannot be changed under any refit. Those items covered under a major refit cannot be increased in size though they may be reduced. Other components may be increased in size if there is tonnage available. If several systems or components are being removed or replaced in a single refit then it only takes the time required for the longest one to be completed though all costs must be paid.

 

[Anonymous]

Armour and other parts of the ship integral to the hull (such as configuration or reinforced structure) cannot be changed under any refit. Those items covered under a major refit cannot be increased in size though they may be reduced. Other components may be increased in size if there is tonnage available. If several systems or components are being removed or replaced in a single refit then it only takes the time required for the longest one to be completed though all costs must be paid.

Where is that quote from?

I couldn't find that in Mongoose 2 Core or High Guard using the PDF search for "refit".

edit: Google found it in Mongoose 1, Trillion Cr Squadon. I'm not even sure what happens now in Mg2.

edit: I don't have Mongoose 1.

 

[baithammer]

Armour is an outer layer that protects the hull from taking damage, although there are designs that place the armour inside the hull and uses the main hull as a sort of spaced section to reduce the energy which potentially lightening said armour plating.

It is however not a trivial undertaking and would require design work before being able to upgrade the vessel.

An alternative to fighters would be expandable armed drones, which could be sacrificed in order to allow for a fast exit jump.

Can convert the 200t hold into launch tube / recovery deck for 10t fighters. ( Store the fighters in the launch tubes during transit.)

 

[baithammer]

Double post

 

[PsiTraveller]

I'll throw my hat into the ring on this. I have some questions.
What Tech level is available?
Are there any weapons not allowed?
What is your fight doctrine? Long range or close and kill? This may depend on what armour the ship has.

You have some options. If you are willing to throw money at the problem then it is easy.
1:Crew: Assume a cost for elite combatants and get the extra DM's to your combat roll. (pg 87 Core book)
2: Computer and software: A max Tl computer or Core computer to run all the extra combat software. This could include Fire Control or Advanced Fire Control, Launch Solution, Virtual Gunner etc. The aim is to get those extra bonuses to do the Effect bonuses.
3: Turrets, barbettes or bays. Depending on the range you want to fight at you have options. DO you want to put 50 tons/ 10 Particle Barbettes and irradiate the enemy until they glow? Very Long range weapon that can do crew hits of radiation (2D X 20) X 5 for spacecraft for 700 rads of exposure per barbette. That's 6D and sterility for an instant hit.
Or you could go for triple Pulse Lasers and missile racks. High tech missiles for the extra damage.
4: Bay weapons: As others mentioned Bay weapons can swamp in a lot of missiles or other weapons.
5: Docking Clamps: Add M-Drive and J-Drive tonnage to allow the ship to move the extra tonnage and you can add 1 ton docking clamps. Each clamp can carry up to 30 tons of fighter. These are not fast lanching but you can strap on extra ships to help defend the ship or attack other ships.
6: External Cargo Mounts: Again add extra M-Drive and j-Drive to allow extra ships to be strapped onto the hull for transport. If the ships are large enough to have a stateroom maybe they launch and a crew hotbunks for a duty cycle. This gives a cloud of ships to do extra damage.
7: Repair Drones and a Workshop: Keep the ship in the fight by stating the ship has the ability to repair damage. Carry spare parts and hull plating.
8: Pack on the M-Drive: Thrust 9 to run away or close in for the kill.
9: Extra power plants for energy weapons, and batteries if you are a power poor ship. A few tons of batteries can last the length of your average battle.

And I know the following statement will open up a debate:
Any ship in Traveller can be a warship. All ships get 1 hardpoint per 100 tons. Cargo ship or combat ship. So 15 triple turrets filled with weapons are going to pack a punch. Combat oriented ships may have bay weapons and do more damage, but a cargo ship, giving up cargo for turret space can pack a nasty punch. The Fer de lance ship has no armour and 10 turrets, so your 15 turrets will happily damage an escort ship, even without bay weapons.

 

[phavoc]

Armour and other parts of the ship integral to the hull (such as configuration or reinforced structure) cannot be changed under any refit. Those items covered under a major refit cannot be increased in size though they may be reduced. Other components may be increased in size if there is tonnage available. If several systems or components are being removed or replaced in a single refit then it only takes the time required for the longest one to be completed though all costs must be paid.

Armor only works if there is structure underneath to support it. So a major refit would be / should be required to change a ships armor factor. Though, to be fair, I would say if a ship was already armored then it could gain 1 pt of armor without a major refit. Having no armor means you'd have to build the structure to support the armor, and since most civilian ships should be armor factor zero, you wouldn't be able to refit one without basically building a new one.

An interesting question is at what point does it make sense to do a major refit on a ship? There would be financial, fiscal and political reasons, not necessarily related to one another. In ye old battleship days ships took a long time to build, the guns were ordered years in advance, so new calibers were very rare, but it was not unheard of for navies to gut them and replace coal-fired boilers with oil, add armor, add torpedo bilges, or in the most radical cases significantly lengthen the ship.

In "modern" navies we don't see that. US carriers get SLEP upgrades, smaller ships get refits, but for the most part it's more electronics and lighter weapons. In the case of the freighter in question it could be much like the jeep carriers the US built on liberty ship hulls, or some of the Q-ships built by both the UK and Germany where they didn't build a warship from the keel up, they just added some light armor and hidden guns to existing freighters and liners. It's certainly something that is technically do-able, though at some point it would get cheaper to build a true warship than convert a freighter into anything more than an armed auxillary. Granted desperation will get you doing things you might not normally do...