I think it fair to say that my 48 was front to back or should that be back to front. An awfully big bang and I can well understand how that South Korean vessel was blown in half!!
The weapon is designed so
the explosion creates a steam void in the water below the keel of the ship whilst breaking it's back. The weight of the ship is left supported by the bow and stern which are now not strong enough to support the weight and the ship breaks into 2 halves as it collapses into the void, as can be seen in the video.