At the end of the Napoleonic Wars, Brace remained in service and took command of the second rate HMS "Impregnable" under Rear-Admiral David Milne, participating in the Bombardment of Algiers in 1816. During the battle, Brace miscalculated the position of his ship and anchored too close to the gun batteries defending the port, preventing his men from depressing their guns sufficiently to inflict any damage on the fort while coming under heavy bombardment themselves. "Impregnable" suffered 210 casualties in the engagement and Brace was blamed for the losses and refused any form of reward from the British government. Instead he was awarded the Military William Order and the Order of Saints Maurice and Lazarus from the Dutch and Sardinian governments and later presented with the Order of Charles III by the Spanish government for his services during the Peninsula War in 1811.