Installing Laser Cannons on Ships:

[Hetzer]

Apparently I could put in an additonal lasercannon putting all other weapons at -1 capacity

 

[OrangeBurner]

I can second this but instead of the laser cannon it's the thermal projector cannon in which I can buy four of.



Edit:
It has something to do with the ship's current fixed equipment (Given that that's where the bought weapons show up on the ship stats).
I'm currently driving the Sledgehammer which does have the Thermal Projector Cannon as its fixed weapon.
(I'm assuming Hetzer is driving the Casstech Z14 which has a Laser Cannon has a fixed weapon).

Too add more to this: after I've brought my 4 Thermal Projector Cannons, I can then checkout and then buy 4 more for a seemingly infinite amount.


So, I can become a very inaccurate weapon.



Attached a save if anyone's intrested.

 

[Hetzer]

Nope I'm driving around the Clydesdale and somehow completly borked the fixed equipment