Bigger ship might take longer to get to Iraq with in the time frame. We could have sent INS Jalashwa but it might be at the eastern command so it will take it time to get there. I guess we also have to take into account that a destroyer can also do the job of fighting off any attempted attack on the ship or national in case of attack by militants.why a fighting ship? India Navy don't have any other ship to do that like LHD or LPD?? Viraat may have accommodate more people and with heli they could have done it much better then a fighting ship.