Newcomer / Intro Understanding shield generators

[GTXPlayer]

Hi,

I'm trying to understand shield generators, but I can't seem to figure out why I can't mount the shield generator I want on my ship. Me and a friend have tried figuring it out, but ultimately we can't understand what the game is trying to tell us.

My Max hull mass is 420, with 275.9 used. It requires says that the max hull mass raises by 138.0 tones, which is 275.9 + 138.0 = 413.9 which is still lower than the max, which I assume is ok.

I have no idea what Optimal Mass is because that wasn't shown anywhere

That's all I can figure out.

Here is the image:
http://imgur.com/M144mEn

Can anyone explain why I can't fit this on my ship.

 

[Chris Simon]

The maximum hull mass that A2 generator can shield is 138 tons. (see the description)
Your Cobra weights 257, so there's no way that generator can shield your ship, so the game doesn't allow you to equip it.

You must equip a generator that has maximum mass higher than the weight of your ship.

Imagine the shield like a rubber balloon which you are trying to stretch over a object.
As you stretch it, it becomes thinner the bigger the object is, until it can't take it any more and it bursts.

Optimal mass of the shield is the ship weight with which the shield will work optimally (aka the balloon isn't stretched too much and stays thicker) that means that the bigger shield you equip the better it will cover your ship.

(Drop mods a line to get rid of the duplicate thread)