General Discussion

to kill on sight.

First you have to be sure what you are looking at either by uniform or other insignia or by intention of the combatants. Operating a boat ( a small boat at that ) in international water, which did not appear to be shooting at anyone or even having any kind of weapon to shoot at someone is completely insufficient to order the killing of the people on board. The Navy commander that ordered this will need to stand trial for either murder or a war crime ( although there is no declared "war" here ).