Complex sentence: The sides of the boat are then made with 20 to 30 adjacent strips of bamboo and then this frame work is again strengthened by light weight bamboos, making sure that the sides are not heavier to the base.
Split into simpler sentences: The sides of the boat are then made with 20 to 30 adjacent strips of bamboo. Finally this frame work is again strengthened by light weight bamboo, making sure that the sides are not heavier to the base.