The formula is more complex than just attack - defense. If this were true, many ships could be 1-shotted. It is based instead a hyperbolic tangent formula, random variances, and a single shot damage cap. The damage cap means that it has to take at least 4 shots to disable any ship (even a level 1). If you have raised your shields/hull, only to see it get hit harder, this is because the cap was applying to you.

I think the hull repair right now is too expensive, scales too fast, and I will adjust it tomorrow.

Here is some more detail on the role each of the various ship defenses offer:

Defense Modules (thrusters & dampeners): These modules allow your ship to avoid damage altogether, without putting strain on your shields and hull. The downside to defense modules is that they take up more space than other types of modules. You can have up to 8 defense modules installed in total (4 thrusters and 4 dampeners). Having no defense at all means that enemy weapons can often do a lot of damage in a single attack.

Shield Modules: These are your first defense for attacks that strike your ship. Having a lot of shields can prevent expensive repair costs on your hull. Since shields regenerate even when you are not playing, they provide an important defense for random attacks. Shields take up less space than defense but more space than hull modules. Another downside to shields is that they cannot be reset to full like a hull, so you are at the mercy of their charge rate.

Hull Modules: These are the last line of defense before your ship becomes disabled. While these do not take up much space, they become increasingly expensive to repair as you gain Ranks, which may require you to rely on an Allly member to repair you.

Totally agree! I love, absolutely love the developers making this a game of balance. If you go all defense, then you shouldn't get 70% attack power (i.e. Castle Age). That doesn't me you can't fight back. It may take me longer to pound down, but drops of water carved the Grand Canyon!

So, which of these modules should one focus on building the most? Defense? Shield? Hull? Or a good mixture of all three? and in what proportion?

Is the damage you receive based on the size of your deck space, or the size of your shields/hull, or a combination of both? from the thinking of 2 ships with 20 deck space one with 100 hull and one with 50 hull both attack and defenses are the same. would the damage be the same. or does the ship with the higher hull take more damage? sorry for the silly questions just trying to understand where to put my rank points and tech in. any advice would be helpful.

it was just what i was thinking of trying. would help on my slow play style and make off line defenses much easier to maintain. thank you for your responses.

I think the hull repair right now is too expensive, scales too fast, and I will adjust it tomorrow.