This submarine is over 2 feet long, so there is plenty of room on the inside for all the mechanical components. You can see some of the flat white piece I used for the torpedo tube on the lower front. As for the fiber optics, the tower is 6 studs wide, and you can even see 3 small dots on the side. You are right, the wires for the radar's motor and the fiber optics are very compressed, which is why I was only able to squeeze 6 fiber optic cables, 3 on each side, instead of the total 8.
About this creation
All controls are hidden in buttons on the top. The bottom conceals hidden wheels that drive the submarine. The rear propeller spins; the radar spins, and fiber optics light up in the tower. Two torpedoes shoot out from ports in the front, and a missile pops out from a hidden panel in the front and shoots almost 8 feet high.