What timberclads could withstand

How effective were timberclads during the American Civil War?

Better than no protection, though they absorbed damage by creating splinters; timber was also useful as backing behind iron armor.

Timberclads offered meaningful protection compared with an unarmored vessel during the American Civil War. Their weakness was that shot striking the timber could throw dangerous splinters through the ship. Wood nevertheless retained value as part of a composite protection scheme. HMS Warrior's teak backing behind iron armor helped manage the effects of impacts and spalling. Timber was useful protection, though it was not equivalent to an ironclad belt.