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?