you cannot make a GBs gun do as much damage as a supernova cause a GBs power replenishes from zero to full in less than 10 seconds, while it takes twice as much for a bomber.
furthermore, - as it was described, two gunboats can easily rip a bigger ship apart by doing the legal shield running ( falling back in turns when the shield is low ) - they are too strong in both hull strength and shield strength to be given a weapon of such power.
the very maximum a gunboat gun should do is something like 40.000 - but only when the projectile was slowed down so that the gunboat has to either get close to the target - or needs someone that has the attention of the target. ( like fighters / bombers ) while the gunboat is doing the artillery job.
so the suggestion is not only to balance out damage and refire / energy - but also the proj. speed.
the basic GB should be the one we have now..
the powerful version should be at lesat 30% slower, twice the damage and twice the energy needed at greater refire rate. - either that or quad the energy use ( like the ratio from a basic gun to a cerberus ) - but keep the refire rate - so one can do bursts but draining the energy quickly.
in all cases, the energy of the GB must be rebalanced so it does not refill so quickly. - the range of such a gun could be 2000 - however, even if the projectile speed was down to 200ms - it would need balancing and testing, especially the two GB vs. 1 big target ... if there is actually a chance to fight the GB off.
No one was saying for it to as powerful as a supernova just using a the whole energy bank for the same damage energy ratio. It means you only get to fire it once instead of three times.
Although thinking about it now it probably should be as powerful as a supernova if its realism your after.
ok was looking at the numbers
Supernova 132000 Hull 66000.00 shield
Rheinland Forward 20000 Hull 10000 Shield
thats the most powerful forward gun at the minute
so even if it was tripled it still wouldn't be even half as powerful as a Supernova.