Until the middle of 16 AD the tower was not adapted for using artillery fire. It's height reached was about the current 5 th floor. During Eric XIV reign in the 1561-1564 a total reconstruction of the tower began. Master from Germany Iogann De Porte directed the work. Tower was disassembled to the level of the third floor and 5 new brick floors were built on the old stone foundation. Two upper floors of the tower were made is in the form of an octahedron.
In the picture on the left is seen the equipment range markers to navigate through Vyborg Bay.