Defensive Screens Math?

[Galadrin]

I had another rules question, but I thought it would be better to start a separate thread for it.

The math for defensive screens in ship to ship combat appears to be wrong. In general, it costs at least 60% of you EUs to put up full screens (much more if you start at fewer than full EUs), but that makes you barely twice as survivable (so a net loss). For example, a Destroyer with 100 EUs will drop down to 40 EUs when full screens are activated, and these remaining EUs will be worth 84 EUs on average for soaking damage. Things get even worse if you spend a few EUs to make attacks or do other things (say you also fire both beam banks... Your 30 EUs are now only worth 63 EUs on average, where you would have had 90 EUs if you chose not to activate screens in the first place). And it's not much better for half-screens, unfortunately, where you pay at least 30% of your EUs (if not more) and gain a little bit more than 1.5x durability, on average (for the aformentioned Destroyer, this leads to a small net gain in durability until you reach 85 EUs prior to activating the half-screens, at which point it becomes increasingly a loss). To show an extreme case, a Destroyer with 65 EUs that activates full screens has made itself 600% more vulnerable by doing so (dropping its average defensive soak from 65 EUs to about 10). Note, this is mathematically true whether or not you fire first or activate screens first. For example, if you activate screens when you still have the full 100 EUs and then spend 35 EUs over the next few turns firing weapons, you will have the same effect.

So am I reading this incorrectly? Does activating screens in the majority of situations actually make you much more vulnerable? The problem seems to be that the net gain (200% or 150% durability) is unconnected to the cost in durability (which might be 60% and 30% at full EUs, but can quickly become 90% loss or more if you do all the other things expected in ship to ship combat, like fire weapons).

One solution might be that EUs spent on screens can still soak damage (so there is no cost to durability to gain a boost in durability, but rather screens tie up EUs that could be spent firing or doing other things). The downside to that is many battles will end with two ships that still have screen EUs but no energy to actually fire at each other (which doesn't seem very Star Trek-y). The other option might be to reduce the cost of screens, which could potentially make them very powerful (perhaps reduce all current EU costs by half). What do you think?

[az_gamer]

I think the screens rule may need some tweeking too.

However, admittedly in the rules the game is not primarily a space combat simulator and we are encouraged to use whatever tactical rules we like if we don't want to use the provided ones. Secondly, in a game where the weapons are really lethal to begin with screens are probably only intended to keep you alive for a while (as you see often in trek where shields get depleted in combat).

But it is an energy management game so out strategizing the opponent with your use of energy is more important than how many direct hits you can take before being destroyed. In real life a modern naval vessel certainly doesn't want to see how many torpedo hits it can take before sinking... they will try to avoid, out smart, out detect, and out defend against the threat as opposed to soak damage.

And lets not forget that once you spend the EU's on the shields you are good for the day until you either loose them in combat or turn them off. But I agree the cost for shield usage should be a little lower. Or another alternate solution would be to boost your power output... maybe your engineer can work his magic and squeeze out 120% out of your power core to get you a couple of additional beam shots (again a role playing / SM adjudication solution). Don't forget torpedoes cost you nothing in EU's but only have limited ammo. One house rule I came up with was the plasma torpedo which was half the power of an Ion torpedo but due to their size you could carry twice as many). A good shot with your torpedoes to reduce their shields can provide you good opportunity to finish them off with the beam hits. But that's where the strategy comes in and you have to make every shot count. Having a poor gunner and attacking at long range will leave you a sitting duck when the power runs out.

Another great topic.

[Jay_NOLA]

Full screens are not intended for space combat in a case where you actively want to engage the enemy. They seem to be for situations where you need to run away from superior firepower or need the extra protection for navigational hazards.

When you are using full screens you are hoping to get high rolls on your damage absorption rolls you make for each individual hit and are hoping your opponent is getting low damage rolls for his weapons or is not going to be able to press the attack because of the EU requirements and that the chance of being able to absorb more damage will let you survive. The ability to absorb a massive amount damage on good roll is what you want.

Screens also never go out until you turn them off or can't afford the cost having them on.

One optional rule I've seen used, in addition to letting the engineer make a roll to get more EU, is to let your weapon's office or other character make a roll to get a to hit or damage bonus and other advantage. Maybe your science officer is able to determine a weakness to hit in the enemy by making a roll each turn and getting a to hit bonus or can attempt to do things to prevent a "lock-on" and give the enemy a to hit penalty.

You might also want to put in a limit to the number of ion torpedoes that can be launched each turn too.

Another optional rule might be to give ships a damage capacity and say that is equal to your normal max EU. Damage is absorbed from that and a percentage is also taken from your EU from each hit the enemy delivers and that a hit can also just cripple EU. (A damage location table may be in order to make or rules for just targeting engines.)

Also note, that space combat in Trek series is cinematic, inconsistent, and story driven. The captain and crew are not fully utilizing all the tactical advantages of a ship. They are using what the writer has decided they will use and what the SFX budget will allow.

[Galadrin]

I gave the rules another read through and noticed that I DID have some of the rules incorrect. Ships are destroyed at 200% PPB damage, not 100%. That means that a Destroyer with 100 EUs could either spend 60 EUs for full screens (the remaining 140 EUs are worth about 300 damage points) or spend 30 EUs for half screens (the remaining 170 EUs are worth about 260 points of damage). Ok, that makes more sense now!

Screens also never go out until you turn them off or can't afford the cost having them on.

I'm not sure I follow this logic... Screens never go out, but you always pay the cost, so you are always down 30% or 60% of your EUs.

[Jay_NOLA]

You EU goes down and you do have to have EU to maintain them every day, but unlike in some other games that have screens (shields) that shield (screen) just gives a random reduction in damage for each hit and they won't go down like in other space combat rules. In other games you have to pay a cost to maintain shields each turn and damage reduction capability of a shield is not a random roll. It absorbs a certain amount of damaged and then is "down" or damaged and you need to repair it if you want it to absorb damage. Damage that penetrates shields in these other games does dame to hull, crew, weapons, etc. S&S screens (shields) are not like Trek ones.