By the default settings in VGA Planets, single engine ships cannot tow. You will want to tow ships for the following reasons:
Dragging suicide ships into battleTowing another ship will consume as much fuel on the towing ship as if it were the mass of both ships combined, so there is no free lunch. If you are towing a ship with inferior engines, you may wish to use the fuel tanks of the towee to store and beam fuel over to the towing ship when needed. That may be used for stealth, as described in the cloaked escort tip, or simply to extend your range.
Freighters towing an escort
Towing a cloaked escort
Pulling an enemy ship into battle
Removing guard ships from your target planet
Tow Capture (Privateers/Crystals)
Towing to your starbase
You cannot tow a chain of ships. That is, you cannot set ship A to tow ship B which is towing ship C. Well, you can, but only one of the two towed ships will move. Exactly which one moves depends on the ship IDs. If two ships are towing the same ship, i believe the towing ship with the lowest ID wins. I am not sure if stronger engines make a difference.
The only ways to break a tow are to have stronger engines than the towing ship, or if your engines are equal, to have your waypoint set to a distance farther than one turn away.
Dragging suicide ships into battle
Frequently you will create ships that are solely intended for suicide missions. (If it helps, think of them as expensive torpedos) There is no point on wasting valuable minerals and megacredits on these ships, so it is typical that suicide ships are constructed with tech 1 engines, which are good for absolutely nothing except being used on suicide ships. Drag these suicide ships into battle using other less-disposable ships. Make sure that they fight first, of course. (Do this using friendly codes)
Freighters are defenseless cannon fodder. There's nothing as tempting as a big fat and juicy freighter flying unescorted through space. When i see freighters all alone in space, i think "hey, free stuff!" This is why you should always escort your freighters if possible. Rather than working to make sure both ships (freighter and escort) arrive at the same pixel each turn, its easy to set the freighter to tow the capital ship escorting it. (you can also have the escort ship tow the freighter, but usually the freighters have a bigger fuel tank) Using the intercept mission on the capital ship may consume more fuel than you need to (it consumes the maximum fuel that it could move in one turn, even if you only move one LY), and prevents the capital ship from using the general "KILL!" mission. Of course, the freighter can always intercept the capital ship, but as mentioned, this may consume more fuel than necessary, and as we all know, you should not waste fuel!
Sometimes you may wish to employ a little subterfuge. You may wish to make it look like there is a fat `n juicy unescorted freighter out there all alone, or you may wish to hide the real strength of your escort fleet from your enemy.
As mentioned in the above tip, it's hard to resist going after an unescorted large freighter. You can use this to your advantage, making the freighter bait for the small to medium sized enemy ships that will fly over to meet it. If you have a particular enemy in mind, set the primary enemy of your cloaked fighting ship(s) to them, and let the spider come to the fly.
Alternately, you may merely wish to escort the freighter, but to hide the importance of it. If your enemy sees you are spending considerable effort to guard a specific freighter, they may rightfully imply that they should divert some of their resources to make sure that it does not reach its destination. Then again, that in itself may be the deception. :-)
Beware! Even though your freighter is towing a cloaked escort, the careful player can still infer the cloaked ship by the amount of fuel the freighter is using! Based on the change of mass on the freighter, they will be able to determine how much fuel it consumed to travel a known distance. From that, they will be able to determine how much mass was moved. If the mass moved doesn't match up reasonably well with the known mass of the freighter (including fuel and cargo), it's a good bet that it's towing a cloaked ship. You can even determine the mass of the cloaked ship, and from there, based upon the ships available to that race, its fuel tanks, and cargo space, you can take a good guess at exactly which type of ship is cloaked! The counter measure for this is to also carry fuel in the cloaked ship, and beam over the appropriate amount to the freighter each turn to make it look like it is not towing a cloaked ship. Sounds complicated? That's what deception is all about! :-)
You may even use that as a deception - if you have a lot of neutronium to burn and you have a very observant opponent, you may use a large freighter and each turn dump fuel into space to make it look like you are towing a big cloaked ship. Fuel is valuable, though. Don't waste it.
Pulling an enemy ship into battle
Sometimes you want to destroy (or capture!) an enemy ship that is travelling with a fleet or orbiting around a planet...unfortunately, that ship is accompanied by reams of other ships that can blow you out of the water. One trick to get the ship you want is bring a cloaked ship to meet the fleet. For the next turn, tow the ship you want to a bigger ship(s) waiting in hiding somewhere, and let the big ship take it out, unencumbered by the firepower of the rest of the fleet!
Removing guard ships from your target planet
Similar to pulling enemy ships into battle, you can also pull them away from the battle! For instance, your enemy may have a planet (or homeworld...muhahahaha!) that is well defended by capital ships. After simulation, you've determined that you don't have enough firepower in the region to defeat the capital ships and to defeat the planet all at once. An easy way around this is to bring in one cloaked ship for each capital ship you don't want to fight while taking the planet. In the next turn, use the cloaking ships to tow the heavy capital ships away from the planet, leaving it undefended, while you move in the fighting ships to take out the planet. It's a good bet you'll lose the cloaking ships - make sure that you pair them up so that they get blown up instead of captured! Don't let your enemy have cloaking ships!
If you are the Privateers, it may be worth it to use MBRs to tow the capital ships to greater than 84 LY (tech 10 distance + 3 LY warp well) away from the planet so they cannot get back for two turns. Hell, if you're the privateers you might wind up capturing the ships. :-) Do not let your opponent capture an MBR, though!
Two caveats:
The Privateers and Crystals, as part of their race abilities, are able to capture ships in space. That is, they do not have to tow you back to their starbase to force your ship to surrender. If your ship is out of fuel, all they have to do is apply their tow beams your ship and it becomes theirs. To compensate for the strength of this ability, Privateers and Crystals are unable to clone ships.
If you want to have an enemy ship without fuel
surrender to you, you must first tow it back to your starbase. (unless
you're the Crystals or Privateers) Put the starbase mission on "Force
a surrender", and all ships with no fuel or with friendly codes matching
the planet (there are some exceptions) will become yours. This is
dangerous,
as although you may get a ship out of it, your enemy will then know where
your starbase is! Choose to do this with great trepidation - the
ship must be worth it, and your starbase must be able to defend itself!
I would gladly exchange some small piddly ship to get information on where
my enemy's starbase is.