That ship was in danger. It was under attack....by the little boat that steered under it's bows.
If I'm driving down the freeway in my van, and a dumb ass on a motorcycle continually veers in front of me trying to cause an accident and I finally fear for my family's safety, I'm perfectly justfied in steering to clip his tire with my bumper if that's what is takes to protect me.
A ship with a fouled propeller is at the mercy of wind and wave until the crew clears the obstruction. That means sending a diver over the side...which is unsafe in the open ocean...and this vessel was under attack, making that operation even less safe.
No, taking action to stop the terrorism from the Ady Gil was justified.