This is one of the best th3 clan war bases to use. At th3 you stand little to no change against bigger players but this layout can withstand attacks from th3 or lower level players.
The town hall is placed in the center to protect it as long as possible. The mortar, archer tower an cannons are placed behind it to protect attackers from all angles.
The other buildings are placed outside the walls to a layer of protection against barbarians and archers.