I'm pretty sure it's because of the nuclear reactor which is in the rear half. The Perle's reactor has still some years to go, and it's much simpler and safer t

I'm pretty sure it's because of the nuclear reactor which is in the rear half. The Perle's reactor has still some years to go, and it's much simpler and safer to simply weld the half containing the reactor, instead of trying to pry it open and move a live nuclear reactor from a boat to the other one.