Complex sentence: They were first deployed in 1916 at the Battle of the Somme in limited numbers, proving unreliable and ineffective at first, as mechanical and logistical issues overshadowed implementing a coherent tank doctrine, with the additional challenge of traversing ground torn apart by years of shell fire.
Split into simpler sentences: They were first deployed in 1916 at the Battle of the Somme in limited numbers, proving unreliable and ineffective at first, as mechanical and logistical issues overshadowed implementing a coherent tank doctrine. These early tanks had the additional challenge of traversing ground torn apart by years of shell fire.