Does shields always mean military? If not, why.cant we then build a civvie rock?Unfortunately our shields are limited to 480 hit points by our tech level. So a ship that was all shield would still be no tougher than a Winged Hussar or Hoplite.
A military Rock with a 480-point shield and very thick armor is possible... but because it is Military it would compete for available slipways with other military ships.