What's the significance of a rocket being launched from under water in 2015 ?
well because historically Russian and U.S Subs before 1965ish had to surface someplace then launch the Missile.
There was two problem with launching under the water. I have not read about it for a while but here is
two cents i remember.
the thrust generated by the missile and the heat could damage the sub.
now missiles for subs actually have an extra stage. the Sub shoots them out.
then there is an extra stage where the Missile has a motor that shoots it out of Water.
Then That stage falls of the Missile and the other stages activate.
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however I think Iran is testing out underwater torpedoes which can be shot out of large speed boats.
It is just a propaganda piece. because of the sheer number of speed boats Iran probably can strike one of the support
vessels that are in an battle group.
remember an aircraft career is basically a sitting duck. it never goes anywhere by itself. it is protected by and supported
within a five mile radius by other ships such as cruiser, frigate, destroyer, logistical ships. which have plenty of defense mechanisms
deployed on them to defend the big ship. and the big itself has airplanes and other systems to defend itself.
because Strait Hurmuz (180 km across) is so small the likely hood that one of the ships in a battle group can suffer some damage definitely exists.
however, that does not mean the battle group will be rendered operationally useless.