I have noticed that the Kraken is supposed to have +7.5% hull but for the same hull build and crew, Arch Dragon and Black Dragon have 19,656 hull points and Kraken has 19,611 hull points. ???

The shield is bigger by 7.5% but that’s not super great on an Empire ship…

once i saw this and got pretty disappointed. Now that i check again i see you are completely right: I dont have black dragon, but comparing kraken without any crew or mod that boosts volume, kraken gets 15208 at lvl 10 synergy, while black dragon gets 15034. A 7,5% difference is obiously higher than 174 between those ships. Considering the base volume of the kraken (excluding volume bonus from synergy) wich is 12723, means a 7,5% increase should be 954,225, total of 13677…if you add now the synergy bonus volume, result is 16162, almost 1k less from what it currently has. BTW, archdragon has 12425 base hull volume (298 pts less than kraken).